vizag steal plant in es& f

5/24/2018 vizag steal plant in ES& F

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Industrial training ES&F, VISAKHAPATNAM STEELPLANT

pg. 1

ANDHRA UNIVERSITY

INDUSTRIAL TRANING REPORT OF A STUDY ON,

ENGINEERING SHOPS AND FOUNDRY.

VISAKHAPATNAM STEEL PLANT

A mini project report submitted in partial fulfillment of the requirement for the award of

degree of

BACHELOR OF ENGINEERING

IN

MECHANICAL ENGINEERING

Submitted by

B UDAY BASHKAR MURTHY 311129520002 B.MANOJ KUMAR311129520003

G.LAKSHMAN LUMAR311129520012 K. CHAITANAYA311129520017

O. HARI KIRAN311129520022

WELLFARE INSTITUTE OF SCIENCE TECHNOLOGY &MANAGEMENT

Affiliated to ANDHRA UNIVERSITY

VISAKHAPATNAM


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pg. 2

. AN OVER VIEW OF VISAKHAPATNAM STEEL PLANT

Visakhapatnam is popularly called as the Steel City of India and credit

was because of the Viza g Steel P lant

a venture of I spat Nigam.VSP i s the f i rs t coasta l based s tee l p lant of Ind ia and i s located

16 km so ut h we st of ci ty of destiny. VSP has an installed capacity of 3

million Tons per annum of liquid st eel and 2.6 56 mil l io n ton s of

sa le ab le st ee l. VS P pr od uc ts me et ex al ti ng international quality

standards such as JIS, DIN, BIS, BS etc.VSP has the distinction to be the first

integrated steel plant in India to becomea ful ly ISO-

9002 cert i f ied company. The cert i f icate covers qual i ty systems,tr

aining and marketing functions spreading over 4 regional marketing officer,

20branch offices and 22 stockyards located all over the country VSP successfully

installing and operating efficiently Rs. 460 cores worth of pollution

control and environment control equipment and converting the barren

land scape by planting more than 3 million plants has made the steel plant, steel

township a greener, cleaner place, which can boas of 3 to 40C lesser temperature

even in the peak summer compared to Visakhapatnam City.

Exports qual i ty p ig i ron and s tee l pro jects to Sr i Lanka,

Myanmar, Nepal , Middle East, USA & South East Asia (Pig Iron). RINL VSP was

awarded StateTrading Housestatus during 1997-2000.Besides these a captive

power plant with a capacity of 247.5 MW, Oxygen plant, Acetylene plant,

compressed iron plant, extensive repair, maintenance facilities, form part of

facilities available at VSP. VSP has sufficient infrastructure to expand the plant to

10 Million tons per annum of liquid steel capacity


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pg. 3

MAJOR PLANT FACILITIES:

VSP has the following major production facilities:

4 coke oven batteries of 67 ovens each having 41.6 M3 Volume.

2 Sinter machines of 312 M3 area.

3 Blast furnace of 3200 M3 useful volume.

Steel Melts Shop with three L.D. converters of 150 Tons capacity each and 6

N0s.of 4 standard continuous bloom casters.

Light and Medium Merchant Mill of 710000 Tons per year capacity.

Wire rod mill of 850,000 tons per year capacity.

Medium Merchant & Structural Mill of 850,000 tons per year capacity.

Besides these a capacity power plant site a capacity of 286.5 MW, Oxygen

Plant, Acetylene plant with Air plant, extensive repair maintenance facilities formPart of the facilities available at VSP.

Number of ovens in series one after the other form a coke oven Battery. At

VSP there Coke oven Batteries, 7 Meter tall and having 67 Ovens each. Each oven

Is having a volume of 41.6 m3 & can hold up 31.6 Tons of dry coal charge.

MINOR DEPARTMENTS: Power generation and distribution.

Water management.

Traffic department.

Engineering shops and foundry.

Utilities department.

Quality assurance and technology development department

Calcining and refractory material plant.


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pg. 4

ENGINEERING SHOPS & FOUNDRY:

INTRODUCTION:-

Engineering shops are set up to meet the requirements of ferrous and

non-ferrous spares of different departments in VSP. The engineering shops manufacture

and repair the needed spare parts of equipment and tools according to the order of the

certain dept., which is called as customer dept.

Engineering shops & foundry is set up to meet the requirements of Ferrous &

nonferrous spares of different departments. Engineering shops &

Foundry is divided into 5 shops.

1. Central Machine Shop.

2. Forge Shop.

3. Steel Structural Shop.

4. Foundry.

5. Utility equipment repair shop.


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pg. 5

CENTRAL MACHINE SHOP

CMS is designed to carry the following manufacturing and repairingactivities.

1) Manufacturing and finishing of castings, forgings, fabricated and

rolled sections.2) Heat treatment and reconditioning of parts

3) Tool room work including manufacturing and repair of jigs andfixtures, regrinding and sharpening of cutting tools

4) Dismantling, repair and assembling of worn out machinery andequipment.

This shop has four longitudinal bays and one cross bay. Heavy and medium

duty machines are located in the first two bays. The third bay has light

machines, for material preparation and tool room. The forth bay houses the

heat treatment and thermal surfacing sections. Cross bay connecting otherfour bays is the fitting and assembly bay and also houses some of heavy

machine tools. Each bay is provided with three EOT cranes with adequatecapacity.

INPUTS: Iron &Steel castings .forgings, rolled sections, repair and rectificationParts, nonferrous castings, fabrication structures.

PRODUCTS AND SERVICE: shafts, pinions, Gears, crane Wheels, Rollers

Machining of various fabrication jobs done in SSS. Repair &reconditioning of

various assembly jobs like L&T housing, To stands, pulleys, previsioning facing and

centering machines ,hacksaws, and gas cutting facilities are provided. The

machining section has over 100 major machine including lathes, milling, boring, and

planning, slotting, shaping, grinding and other machines. The assembly section

undertakes medium repair and general overhauling of mechanical equipment.

Horizontal and vertical presses, washing tanks oil berths etc. are provided. The tool

room has facilities for manufacture of special tools, jigs and fixtures, re-grinding of

tools and brazing of tipped tools. The heat treatment section is provided with

annealing, normalizing , heat treatment furnaces, carbonizing furnaces, heat


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pg. 6

treatment furnace with protective gas atmospheres, high frequency hardening

machine, quenching tanks with oil cooling arrangements, welding generator and

transformers for normal welding, sub-merged arc welding machine etc. Facilities

for surface grinding, pipe bending and threading are provided.

MAJOR JOBS OF CMS:

Repairing and reconditioning of TK stands of continuous castingmachine.

Manufacturing and repairing of different types of gears and

couplings.

Reconditioning of single roll crusher rotor assembly and spiral

classifier assembly.

Repair of machining of cooling plates carbon blocks

Fitting & assembly

section

Central Machine Shop

Machining Maintenance

Assembly & repair

work

Reclamation

Machining Gear cutting

Heat

treatme


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pg. 7

EQUIPMENT IN CMS:

Plano milling machine

Heavy lathes

Horizontal boring machine

Vertical turret boring machine

Grinding machine

Slotting machine

Milling machine

Planning machine

Drilling machine Gear hobbing machine

Gear shaper

Bevel gear generator

Balancing machine

Shot blasting machine

Submerged arc welding

Induction gear hardening machine

HEAVY LATHE;

The HEC LC 100/ LC 125 type center lathes are heavy duty lathe machinesusing in CMS. These are fully satisfying the claims modern technology. Their rigid

structure permits roughing and also precision finishing work. It uses cemented

carbide tipped tools and high speed steel tools.

Working range specifications: LC100 LC125

Swing over bed mm 1000 1250


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pg. 8

Swing over carriage mm 710 900

Height of bed above carriage mm 500 630

Distance between centers mm 3000 12000

Max. Torque kgm 2500 3150

Max. Weight kg 10000 14000Spindle speeds: in 36 steps

First range rpm 1.8-90 1.4-71

second range rpm 8-400 6.3-315

Dia of taper in spindle mm 80/1:10

Main motor speed rpm 1460; kW 40

Longitudinal feeds in 36 steps:

First range mm/rev 0.125 to 6

Second range mm/rev 1 to 48

Movement of:

Cross slide mm 530 650

Compound rest mm 360

Tool post mm 110

Max. Cross section of tool for 4way

Tool post mm 5050

Long. Rapid transverse mm/min 3600

Motor for Long. Rapid transverse rpm 1400; kW 1.1

Dia of sleeve of tail stock mm 170

Dia of taper in sleeve mm 80/1:10

Rate of travel tail stock mm/min 2150

Offsetting of tail stock mm +-10

Motor of tailstock rpm 1400; kW 0.05

Pitch of lead screw inch Motor for lubricating oil pump kW 0.18

The main parts of a lathe are:

1) Bed

2) Head stock

3) Tail stock

4) Carriage


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pg. 9

BED: It forms the base of the machine. On the bed racks for carriage, tail stock, head

stock, and bearings for feed rod and lead screw are fixed.

The bed is provided with 3 transverse holes for lifting. It also act as reservoir for

lubricating oil.

HEADSTOCK: It is on the left side of the lathe bed. It contains the lathe spindle and

spindle driving mechanism. The spindle is hollow throughout its length to allow bar

stock to pass through. It is located and runs in precision anti friction bearings in head

stock housing. The spur gear attached to the left end of the spindle drives the trains

gear to provide motion and direction to the feed rod, quick change gear box and

thread cutting mechanism. This lathe is driven by constant speed motor. Change of

spindle speeds are obtained by a series of gear combinations by shifting two or three

levers in different positions. The main motor is housed in head stock.

CLUTCH and BRAKE: The brake serves to reduce the costing of machine to the

maximum. It applies automatically as soon as the main motor is switched off and is

released again when the main motor is started. The clutch id of centrifugal type

which permits a soft starting and the full torque is gradually built up, starting load

being less, starting current of motor is less.

CARRIAGE: It controls the movement of cutting tool either parallel or

perpendicular to lathe axis. It moves on the guide ways of the bed. It again consists

of:

saddle

compound rest

tool post

Saddle is mounted on the guide ways carriage and supports the cross slide

Compound rest is mounted on the guide ways of the saddle and supports the tool

post. The base of the compound rest can be swiveled to any angle between 0-360o

and mainly used during taper turning operation.Tool post, its main purpose is to hold the tool during operation. There are two types

of tool posts:

standard tool post

four way tool post

The LC100/125 lathes use the four way tool posts.


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TAILSTOCK: or loose head stock is located on right side of the bed. It is used to

support work piece during rotation and to hold drill or reamer during drilling and

other operations. It is provided with set over screw at its base for taper turning

alignment. It has a cast iron body with bore to accommodate tail stock spindle andtop portion contains the feed screw hand wheel, a spindle lock clamp. It slides on

the guide ways of the bed and positioned according to the length of the work. In case

of heavy lathes a special motor is provided to move the tailstock on the bed.

Hydraulics:

The head stock of the lathe houses two hydraulic clutches in the drive system

and one hydraulic brake. The clutches and brake operate at pressure of 10kg/cm2.

The hydraulic system consists of an oil tank fixed to front leg of the machine, a

suction strainer, the gear pump driven by main motor, a relief valve, a pressure filterand a rotary valve.

In VSP central machine shop the lathes up to 1.7m length are belt driven and

lathes of bed length 3m, 5m are all geared headstocks.

Headstock of NH-22 lathe is designed to give spindle 16 forward speeds or 8 forward

and 8 reverse speeds.


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pg. 11

HORIZONTAL BORING MACHINE:

The table type of horizontal boring and milling machine has a wide range of

machining possibilities.

The details of machine used in VSP, CMS:

Type: BH 100

Version: standard/special

Overall length: mm 6000

Overall width: mm 2650

Overall height mm 3050

Total weight kg 13550

Supply voltage 4157 A; 50 Hz; 3Ph AC

The main assemblies of machine are:

HEAD STOCK: It houses the spindles and main drive. The main and hollowspindles are mounted in the radial two row roller bearings with a tapered hole andinn the one row ball nearing. The thrust bearings take up axial loads.

The working spindle has the same revolutions as hollow spindle and is slideable. It is mounted in the bush and in taper bush. This is slit alongside. The torsion

movement is transferred from hollow spindle to working spindle by wedges. Thefeed of work spindle is delivered from thread shaft on the axis by means of feeding

nut, over the plug to extension bearing of the lib.

Die of spindle: mm 100

Taper in spindle: mm 6

Max boring dia mm 560


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Max boring depth mm 900

FACE PLATE: The face plate is solid with main spindle the tool slide, sliding nut

in a prismatic guide. It is possible to take up the lateral clearance by a correctsetting of the adjusting screws. When turning then the position of adjusting wedges

change in relation to prismatic guide in faces plate. Thus the lateral clearance ofthe tool slide increases or decreases.

Dia of face plate: mm 600

Centering dia: mm 280

Depth of Centering dia mm 8

Max. Distance between face plate and back rest mm 2800

COLUMN: The cast iron column has a narrow guide on the right side when

viewing from front. The position of column in relation to the bed is secured, bytaper pins. The space inside the stand serves for the counter weight hangs on achain leading over the pulleys on the top of the column.

BED: The sliding surfaces of beds are to be regularly lubricated, inspected and

looked after the bed ways. The bed must not be used for putting away tools etc.

SLIDE and TABLE: A lever engages different automatic feeds in the group slideand table.

Clamping the work piece:

Work pieces are clamped on the turn table with clamping T-slots. The

medium slot intersects the rotation axis. The centering dia for fixture centering is

turned on the clamping surface in the rotation axis. It is possible to fix

simultaneously by the holder of cooling system with feed piping to this table.

The table may be loaded with a work piece of the max weight of 4000kg oncondition of uniform distribution.

Clamping surface: mm 12501250

Centering dia: mm 180


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pg. 13

Depth of Centering dia: mm 6

Long. Travel of table mm 1250 to 1750

Cross travel: mm 1250

BACK REST: the back rest is provided with an independent asynchronous electric

motor for the vertical adjustment of bearing. The direction sense corresponds to the

position of the changeover switch. The longitudinal movement of back rest is doneonly by hand. For this a crank put on the shaft is rotated. The back rest is locked ata particular position by tightening of screws.

The working principle of machine consists of a coordinate travel of the

individual working groups; vertical feed of head stock; longitudinal feed of the slide

and cross feed of table.

VERTICAL TURRET BORING MACHINE:


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pg. 14

It is a special vertical type of lathe machine. This is used for a large dia and small

depth jobs.

CONSTRUCTION:

Vertical turret lathe has a single turret head and a side on right hand upright.This turret head can be moved rightward and leftward on a cross slide ways. The

cross slide can be raised and lowered on uprights by lever to accommodate

various depths of work, by pulleys and suitable elevating screws. In this machine

work is placed on a vertically mounted face plate and held in chuck. The job must

be carefully balanced and run at a slow speed, owing to vibration caused by the

wear in spindle bearings, whereas with work mounted on vertical spindle, all the

weight is evenly distributed downward on bearing s, so that smooth running

results and heavy cutting is possible. The main drive is by the electric motor to a

gear box giving 18 speeds operated by levers and then to a large ring gear fastenedto the table. Feeds are available in all directions.

OPERATION:

The job is rotated on table and the turret head is lowered and set to the top of

the job and downward feed of turret is engaged. Depth of cut is given by

rightward feed or leftward movement of tool head. If outside of the job is doing

it is turning; if inside of job it is boring; if it is top of job it is facing; the maximum

dia of job is 2.5m to 3m. A pilot bush is fixed in a central hole of table. It has a

series of drilled holes in order to facilitate the escape of cuttings down the hollow

spindle to the floor.


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pg. 15

PLANO MILLING MACHINE:

Plano milling machine is a milling machine, but designed to execute certain work

formerly confined to the planer. It is a multipurpose machine on which milling,

planning, drilling, boring etc. can be done. It has a cross rail, capable of being

raised or lowered, carrying the cutters, their heads and the saddles, all supported

by stout uprights. There may be multiple cutter heads on the rail, as well as two

heads on the uprights. Each cutter head in the Plano-miller is separately driven.

The drive of the bed is through hydraulic system.

The length of the bed is 8 m and the width of bed is 2 m. so that 16 m length

jobs can be done easily. This machine is safe on mechanical side using German

technology. The electrical power to machine is immediately cut off when over

load or any other interruption like lack of lubricating oil etc. is occurred.

Therefore the mechanical breakdown doesnt occur and this machine is running


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successfully from 20 years.

HORIZONTAL MILLING MACHINE:

In horizontal milling machines the cutter is mounted on horizontal arbor by

spacing collars and work is clamped on the table. Horizontal milling machine is

generally used for cutting gears by using indexing and for cutting keyways.

VERTICAL MILLING MACHINE:

In vertical milling machine milling cutter is fixed to the vertical spindle and

work is clamped on the table. It is generally employed for producing flat surfaces.

Because of its multi-point cutter milling machine is mostly preferred than shaper inproducing flat surfaces.

Coolant systems:


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Correct cooling and lubrication of cutting tool faces is important. Coolant

should have following properties:

good cooling effect

good lubrication effect

protection against rust or other chemical influencesDepending upon the requirement of the specific milling operations coolants

may be used.

Supply:

The milling machine is provided with a coolant pump for the supply of

coolant. The sump for the coolant of approximately 35 liters is arranged in the base

of the machine. The coolant pump runs as long as spindle runs and is automatically

switched off when spindle stops. A separate switch is provided to switch off coolant

independently to the spindle when not required.

SHAPER:

SHAPER is used for machining flat surfaces. Machining on shaper is more

economical with better work setting and cheaper tooling. In shaper work is held

stationary on the table and tool reciprocates across the work. The tool used on shaper

is of single point cutting tool, thus the work on shaper is transferred to milling

machine which is a multi-point cutting tool. In shaper material is removed during

forward stroke and return stroke is an idle stroke. The quick return mechanism isemployed in shaper to minimize the working time.

SLOTTER:

SLOTTING machine is used for cutting keyways, grooves etc., It consists of

ram reciprocates vertically and tool is fed to the work piece on the rotating table. Inslotting machine material is removed only during forward stroke & return is idle

stroke. In slotter single point cutting tool is used for the operation. Slotter is mainly

used for internal turning.


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pg. 18

GEAR HOBBING MACHINE:

It is used for machining gears from gear blank. In this machine cutting is

carried out by a tool called hob. The work is fixed on rotary table and the hob isrotated by means of an electric motor and work is fed across the hob.

Operation:

Set the fixture and clamps in the T-slots provided on table. Clamp the work

on the table and check the trueness using dial indicator. Select the type of hob on the

arbor with a lock nut. Set the required helix angle on the hob. Start the machine to

cut the teeth on the gear blank.


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pg. 19

BALANCING MACHINE:

A balancing machineis a measuring tool used for balancing rotating machine

parts such as rotors forelectric motors,fans,turbines,disc brakes,disc drives,propellersandpumps.The machine usually consists of two rigid pedestals, with

suspension andbearingson top. As the part is rotated, the vibration in the

suspension is detected with sensors and that information is used to determine theamount of unbalance in the part. Along with phase information, the machine candetermine how much and where to add weights to balance the part.

HARD-BEARING VS SOFT-BEARING:

There are two main types of balancing machines, hard-bearingand soft-bearing.

The difference between them, however, is in the suspension and not the bearings.

Hard- and soft-bearing machines can be automated to remove weight automatically,such as by drilling or milling, but hard-bearing machines are more robust and

reliable. Both machine principles can be integrated into a production line and loadedby a robot arm or gantry, requiring very little human control.

Working of machine:

With the rotating part resting on the bearings, a vibration sensor is attached to the

suspension. In most soft-bearing machines, a velocity sensor is used. This sensor

works by moving a magnet in relation to a fixed coil that generates voltageproportional to the velocity of the vibration. Accelerometers, which measureacceleration of the vibration, can also be used.

A photocell (sometimes called a phase), proximity sensor, or encoder is used to

determine the rotational speed, as well as the relative phase of the rotating part. Thisphase information is then used to filter the vibration information to determine the

amount of movement, or force, in one rotation of the part. Also, the time differencebetween the phase and the vibration peak gives the angle at which the unbalanceexists. Amount of unbalance and angle of unbalance give an unbalance vector.

Calibration is performed by adding a known weight at a known angle. In a soft-bearing machine, trial weights must be added in correction planes for each part. This

is because the location of the correction planes along the rotational axis is unknown,and therefore it is unknown how much a given amount of weight will affect the

balance. By using trial weights, you are adding a known weight at a known angle

and getting the unbalance vector caused by it. This vector is then compared to the
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original unbalance vector to find the resultant vector, which gives the weight and

angles needed to bring the part into balance. In a hard-bearing machine, the locationof the correction plane must be given in advance so that the machine always knowshow much a given amount of weight will affect the balance.

SUBMERGED ARC WELDING MACHINE

Submerged arc welding machine

Submerged arc welding(SAW) is a commonarc weldingprocess, originallydevolved by the Linde - Union Carbide Company.

It requires a continuously fed consumable solid or tubular (fluxcored) electrode.

The molten weld and the arc zone are protected from atmospheric contaminationby being submerged under a blanket of granular fusiblefluxconsisting oflime,

silica,manganese oxide,calcium fluoride,and other compounds. When molten, thefluxbecomes conductive, and provides a current path between the electrode and

the work. This thick layer offluxcompletely covers the molten metal thuspreventing spatter and sparks as well as suppressing the intense ultraviolet

radiation and fumes that are a part of the SMAW (shielded metal arc welding)process.

SAW is normally operated in the automatic or mechanized mode, however, semi-

automatic (hand-held) SAW guns with pressurized or gravity flux feed delivery areavailable. The process is normally limited to the Flat or Horizontal-Fillet welding

positions (although Horizontal Groove position welds have been done with a
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special arrangement to support the flux). Deposition rates approaching 100 lb. /h

(45 kg/h) have been reportedthis compares to ~10 lb. /h (5 kg/h) (max) forshielded metal arc welding.AlthoughCurrentsranging from 300 to 2000 an arecommonly utilized,[1]currents of up to 5000 A have also been used (multiple arcs).

Single or multiple (2 to 5) electrode wire variations of the process exist. SAWstrip-cladding utilizes a flat strip electrode (e.g. 60 mm wide x 0.5 mm thick). DC

or AC power can be used, and combinations of DC and AC are common on

multiple electrode systems. Constant Voltagewelding power suppliesare mostcommonly used; however, Constant Current systems in combination with a voltagesensing wire-feeder are available.

Electrode

SAW filler material usually is a standard wire as well as other special forms. Thiswire normally has a thickness of 1/16 in. to 1/4 in. (1.6 mm to 6 mm). In certain

circumstances, twisted wire can be used to give the arc an oscillating movement.This helps fuse the toe of the weld to the base metal.

SHOT BLASTING MACHINE:

The major operations of a blast machine are as follows:

Cleaning of metals

Sand from the primary foundry process, rust, paint and powder, epoxy or othercoatings may be removed from metals through the process of blast cleaning.

Normally, the metal is being prepared for another coating process, so it isimportant to remove all matter that would sacrifice the quality of the surface andcause a poor finish.

Descaling mill products

Mill scale produced in the primary process of manufacturing metals is removed by

blast machines. Plate, sheet, strip, wire, bars, billets and other products can bedescaled.

PeeningmetalsIn the peening process, a stream of metal particles is applied at a high velocity viaa Rot oblast wheel against the surface of a metal part. The contact alters the surface
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of the part and creates a rounded depression where the edges of the depression will

rise slightly above the original surface. Aircraft components, gears, springs andother critical parts undergo peening operations.

BLAST MACHINE OPERATION IN 10 STEPS

Most wheel blast machine systems operate as follows:

1. Steel abrasive is conveyed into a hopper which is located in a position that istoward the middle of the system but higher than the Rot oblast Wheels.

2. An abrasive gate located above the wheel controls the abrasive through a feedspout toward the Rotoblast wheel.

3. In the Rotoblast wheel is an impeller that rotates. The feed spout directs the

abrasive toward the rotating impeller and the impeller directs the abrasive to anopening in an impeller case.

4. The impeller case then directs the abrasive towards the vanes. The vanes areconnected to a runner head, which is being driven by an electric motor system.

Direct drive motors rotate the runner head at 1800 or 3600 RPM. For bearing andspindle drives, the speeds can vary from 2100 to 3200 RPM.

5. With the vanes rotating at a high speed by the runner head, and the abrasive

being fed onto the vanes, centrifugal force hurls the abrasive at high speeds toward

the work to be cleaned.

6. The steel on steel contact cleans peens, descales or performs other functionsdesigned into the system.

7. After contacting the work, the spent abrasive falls into a recovery hopper alongwith other non-abrasive materials (sand, scale, etc.) which has been removed from

the work. The recovery hopper is located below the work that is being cleaned.

8. The recovery hopper has a screw conveyor, or oscillating conveyor that conveys

the material toward an elevator belt. The elevator belt, driven by another electric

motor, is equipped with buckets that carry the material to the very top of thesystem.

9. At the top of the system is a scalping drum or another screw conveyor that

initiates a process where good abrasive is separated from foreign matter. Thescalping drum detects larger contaminants compared to the size of the abrasive. It


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directs the larger contaminants toward a scrap drum on the floor, and sends the

balance of the abrasive toward a separator which detects abrasive that may be worndue to use.

10. The separator discharges the good abrasive into a storage bin and recycles to

the Rotoblast wheels. The spent and broken abrasive is discharged out of thesystem and into a refuse container.

HEAT TREATMENT SECTION:

It is a post machining operation and is carried out for changing the

structure and properties of metals and alloys by controlled heating and cooling.

It is performed to relieve internal stresses, refine grain size etc., the heat treatment

section in VSP machine shop consists of:

3 heating furnaces

Oil bath

Water bath

Induction hardening furnace

Carburizing furnace

Nit riding furnace

INDUCTION HARDENING FURNACE:

Induction hardeningis a form of heat treatment in which a metal part is heated by

induction heating and then quenched. The quenched metal undergoes a martensitic

transformation, increasing the hardness and brittleness of the part. Induction


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hardening is used to selectively harden areas of a part or assembly without

affecting the properties of the part as a whole.

Process:

Induction heating is a non-contact heating process which utilizes the principle ofelectromagnetic induction to produce heat inside the surface layer of a work-piece.

By placing a conductive material into a strong alternating magnetic field electrical

current can be made to flow in the steel thereby creating heat due to the I2R losses

in the material. In magnetic materials, further heat is generated below the Curie point

due to hysteresis losses. The current generated flows predominantly in the surface

layer, the depth of this layer being dictated by the frequency of the alternating field,

the surface power density, the permeability of the material, the heat time and the

diameter of the bar or material thickness. By quenching this heated layer in water,

oil or a polymer based quench the surface layer is altered to form a martensiticstructure which is harder than the base metal.

Principal methods;

Single shot hardening:

In single shot systems the component is held statically or rotated in the coil and the

whole area to be treated is heated simultaneously for a pre-set time followed by

either a flood quench or a drop quench system. Single shot is often used in caseswhere no other method will achieve the desired result for example for flat face

hardening of hammers, edge hardening complex shaped tools or the production of

small gears.

Traverse hardening:

In traverse hardening systems the work piece is passed through the induction coil

progressively and a following quench spray or ring is utilized. Traverse hardening

is used extensively in the production of shaft type components such as axle shafts,

excavator bucket pins, steering components, power tool shafts and drive shafts.The component is fed through a ring type inductor which normally features a

single turn. The width of the turn is dictated by the traverse speed, the available

power and frequency of the generator. This creates a moving band of heat which

when quenched creates the hardened surface layer. The quench ring can be either

integral a following arrangement or a combination of both subject to the

requirements of the application. By varying speed power etc. it is possible to create


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a shaft which is hardened along its whole length or just in specific areas and also to

harden shafts with steps in diameter or spines. It is normal when hardening round

shafts to rotate the part during the process to ensure any variations due to

concentricity of the coil and the component are removed.

Equipment:

Power required:

Power supplies for induction hardening vary in power from a few kilowatts to

hundreds of kilowatts dependent of the size of the component to be heated and the

production method employed i.e. single shot hardening, traverse hardening or

submerged hardening.

Frequency

Induction heating systems for hardening are available in a variety of different

operating frequencies typically from 1 kHz to 400 kHz. Higher and lower

frequencies are available but typically these will be used for specialist applications.

The relationship between operating frequency and current penetration depth and

therefore hardness depth is inversely proportional.

CARBURISING FURNACE:

It is used for case hardening of products are done. In this process the heating

is carried out up to 600oC for 4 hours at 150oC/hr., and then holding for half an hour

at 600oCtaken place, again heating takes place at the rate of 61oC/hr. to 875oC. Thus

the heating cycle is completed and cooling is done by quenching them in the water

bath.

The main components which are heat treated in this section are Bull head hammers

of flux crushing plant in the sinter plant, gear blanks etc.


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pg. 26

Horizontal Boring Machines:-


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pg. 27

Radial Drilling Machines:-

Universal Drilling Machines


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pg. 28

Milling Machines:-


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FORGING SHOP:In forging shop, the parts and objects which are needed high strength and hardnessthat required to VSP.

Forging is one of the oldest hot metal working processes. It is defined as theshaping of a heated metal by hammering and pressing. In this process metals are

made plastic by heating them and deformed by hammering while they are hot. Thecomponents made b this are called forgings. The process is carried out atrecrystallization temperature of metals.

INPUTS: Ingots from foundry, blooms from SMS, billets, rods from mills etc.

PRODUCTION AND SERVICES:Raw material for shafts, coupling, gears, pinions, Flanges bull head hammers for

plant hammer crusher, drill rods for blast Furnace, v-hooks for SMS, straightening

of pallet frames of sinter plant. The shop is designed for production of shafts,

coupling: - flanges Etc. and also of forged shapes such as crusher hammer heads,

special bolts, nuts, Etc. The repair and testing of chains are also carried out. Theannual production from the shop is about 2,400 tons based On 300 working days

per year and two Shifts per day. These inputs consisting of ingots, billets, blooms

and flats of various sizes. In heavy forging section, open die forging of long shafts,

gear blanks, couplings etc.is made with the help of 2-ton bridge type pneumatic

hammers. Each hammer will be provided with thin chamber heating furnaces.

Floor type manipulator and jib Crane are provided for handling heavy jobs. In

general forging section, 1 ton, 500 Kg, and 200 Kg hammers with separate heating

furnaces are provided. A 2 ton drop stamp hammer with a heating furnace

trimming press etc. is provided for stamping. For cutting them to size, a cold saw,a billet shear and gas cutting facilities are provided. For stress relieving, bogie

type-annealing furnace is provided.

HEAVY FORGING BAY:


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In this bay, the jobs which needed a large deformation and the large jobswhich required high forces to deform are done.

General heavy forge jobs;

Squares to rounds (shafts)

Round to hexagon

Gear blanks

Stepped shafts(bottom roll shafts)

Bull head hammers etc.

Raw materials:

Blooms (rectangle) 240 * 320 mm

Squares 240*240 mm

Ingots larger dia 350mm; smaller dia 240 mm

Equipment in this bay:

Heating furnaces4

Bogie furnace for heat treatment 2 ton & 3 ton pneumatic hammers

Manipulators2; 1 T & 2 T capacity

LIGHT FORGING BAY:

In this bay the jobs which need light deformation and smaller in size are done.

General light forging jobs:

Mud guns (4000; 3500; 2500 mm length)

Tongs

Squares etc.

Equipment:

Pneumatic hammers1.6 T


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pg. 31

500kg hammers2nos

250kg hammers1 no

Open hearth furnace1

Drop stamp hammer

Trimming press

TOOL ROOM:

It is provided to cut the shafts, billets, making holes etc.

Equipment:

Circular saw

Power hacksaw

Band saw Drilling machine

Shaping machine

Grinding machine

Billet shearing machine

TYPES OF FORGING:

There are many different kinds of forging processes available, however they can be

grouped into three main classes.

Drawn out: length increases, cross-section decreases

Upset: Length decreases, cross-section increases

Squeezed in closed compression dies: produces multidirectional flow

Common forging processes include: roll forging, swaging, cogging, open-die

forging, impression-die forging, press forging, automatic hot forging and upsetting

OPEN-DIE DROP-HAMMER FORGING


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In open-die forging a hammer comes down and deforms the work piece, which is

placed on a stationary anvil. The dies (the working surfaces of the forge that contact

the work piece) do not enclose the work piece, allowing it to flow except where

contacted by the dies. Therefore the operator needs to orient and position the work

piece to get the desired shape.

IMPRESSION-DIE DROP-HAMMER FORGING

Impression-die forging is also called closed-die forging. In impression-die work

metal is placed in a die resembling a mold, which is attached to the anvil. The

hammer die is shaped as well. The hammer is then dropped on the work piece,

causing the metal to flow and fill the die cavities.

PRESS FORGING

Press forging is variation of drop-hammer forging.

Press forges work slowly by applying continuous pressure or force. The amount of

time the dies are in contact with the work piece is measured in seconds (as compared

to the milliseconds of drop-hammer forges). The press forging operation can be done

either cold or hot.

UPSET FORGING

Upset forging increases the diameter of the work piece by compressing its length.

Engine valves, couplings, bolts, screws, and other fasteners.

ROLL FORGING

Roll forging is a process where round or flat bar stock is reduced in thickness and

increased in length.

HEATING FURNACE:


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The furnace is equipment used to provide heat for a process. Inn this type offurnace, a room type fixed hearth gas fired heating furnace is used.

The pilot burner and main burner in two sets are at roof. The coke oven gas issupplied to burner and is burnt with the air provided from an air blower. Differentvalves are provided for air and gas controls.

Operation of furnace:

A. starting procedure:

2) Informing to gas control departmentindicating the starting of furnace.

3) Observe the water over flow condition to ensure that U seal is full of water

or not.

4)

Ensure that there are no any defects in gas line fitting.5)Remove if any blanks in gas line

6) Keep the furnace door and damper open.

7) Keep the main isolation switch of electrical panel in on position.8) Switch on the individual feeders.9) Start the blower after blower discharge valve close and then open the valve.

U seal dewatering process:

a. Close the water inlet valve of u seal and open the drain

valve to escape water.b. Close the over flow valve line and drain valve after

escaping of water

10) Open the gas valve and check the pressure whether it is 500-600 mm of

water column.11) Energize the solenoid and reset the annunciation.12) Set the required temperature in controller.

B. Lighting the burner:

13) Keep the main burner air valve close while the pilot burner air valve ispartially opened.

14) Lit the pilot burner by opening gas valve.

15) Open the gas and air valves of main burner.

16) Open pilot air valve completely while pilot gas valve is closed.17) Above same procedure is followed for second set of burners.


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18) Close the furnace door and check the flame is stable or not.

When the furnace room temperature is 900 deg C the jobs are introduced. Theforging temperature is up to 1200 deg C.

C.

19) Inform the gas control dept. that furnace is fired off.

20) Close the main airline valve and accept the annunciation.21) Close the main burner gas line valves.

HEAVY FORGING HAMMER:

It is a bridge type pneumatic hammer.

Construction:

The machine supports on two columns. Two columns are joined with an arch whichforms a multi prismatic guide of mono block type cylinder at center. A ram is slide

inside the cylinder and the top die is fitted to the ram. The bottom die is placed on

an anvil located below top die. A stuffing box which houses valve controls is placed

before entrance and exhaust of the cylinder. The machine and anvil are installed with

strong and deep basement i.e. 25to 35 feet to make the machine robust to absorb highshocks.

Operation:

The top die is the actual tool which performs the hammering action. The die

is operated upwards and downwards in cylinder by air pressure. The inlet and

exhaust valves are controlled by a lever which is connected to stuffing box. When

upper inlet valve is opened, the highly pressurized air is supplied into the top of thepiston from Air Separation Plant, Utilities dept.. Then the ram moves downwardsand blows on the job, which is placed on the bottom die. The air below the ram is

exhausted through lower exhaust valve. There is a top pressure buffer cap in cylinder

which inserts the ram safely by an aid cushion at the end of its upward stroke. Thecylinder and ram is lubricated with oil for free and smooth movement.


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pg. 35

LIGHT FORGING HAMMER:It is widely used for the manufacture of medium size forgings. The ram is

directly connected to piston working in a steam or air cylinder. The capacity of

column hammer is about 500kg.

It operates with steam or compressed air. As compared to pneumatic bridge

hammer, column hammer does not possess built in compressor and therefore,

requires additional arrangement for supplying high pressure steam or compressed

air.

Pneumatic column hammer

DROP STAMP HAMMER:

It is a closed die forging hammer. Spanners, nuts, bolts etc. are made by thismethod. The dies are made for these jobs, they can produce at rapid rate

because as fast as the heated lumps of steel are taken out of furnace they can beput into drop stamp, pounded by it with dies to the required shape and thenremoved to have the surplus metal cut off.

Mechanism and operation of this hammer:

This hammer is used the friction lift mechanism. This consists of two multigrooved friction drums fixed to the main shaft. A one piece cast lifting arm is fitted

between these two drums and is mounted on anti-friction bearings are carried on

main shaft on the outside of each drum cast steel lifting levers are tied to the lifting


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arm by the tie plate and a cam spindle is carried through arm and levers. Frodo-lined

Vee brakes operated on the cam spindle by means of a control lever at one end ofthe lifter and engage with the friction drum, which is fixed to the revolving main

shaft. Thus by a pull on the control lever, the stationary lifting arm, levers and brakes

are locked with drum and the lifting mechanism is put into the operation. Thehammer head is connected to the lifting arm by means of a belt, which is guided by

a loosen pulley bushed on to the lifting arm. The main shaft carries a fixed winch,around which is a control rope is worked by an operator, who by a slight pull can lift

the hammer and hold it at any position in guide rods. The drive is by means of anelectric motor placed in a suitable position on the floor engaging by a belt to a heavy

fly wheel driving the main shaft through a single train to accuracy machine cut gears.

The process includes providing a super abundance of power over the live

weight which it has to control by lifting, mechanism such that the forger can obtain

that sharp elastic snappy blow when it is left over the job that immediately theinstantaneously merged together.


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MANIPULATORS:-

Manipulators are used to hold the heated jobs while the forging operation is

doing on heavy forging hammer. It has two jaws which can be rotated around 360

deg. When maximum flexibility in transport and handling capabilities during theforging process is important a Mobile Forging Manipulator is your first choice.

The compact design and maneuverability of manipulators from DANGO &

DIENENTHAL allow the transport of work pieces even when space is limited.

Whether small or very large handling capacities are needed DANGO &

DIENENTHAL offers both standard and customized solutions. Our machines offer

high reliability as well as great flexibility. The sturdy and compact design is

adapted to the special operating conditions.

Ergonomically aspects and hands-on experience are the decisive factors for

selecting and arranging control levers, switches and buttons.

Characteristics:-

Powerful tongs unit with large gripping range

Multistage adjustment of closing force

Spring systems acting both vertically and horizontally to absorb shock loads

High maneuverability due to quick and flexible travelling behavior

Semi-automatic working cycles at request

Travel, steering, and tongs motions can be carried out at the same time excellent

operator's view in all directions air conditioned driver's cabin atrequestpumpsdriven by electric motor or diesel engine Emergency functions

BOGIE FURNACE:

Abogie furnace is used for heat treatmentof the forged jobs.


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BILLET SHEARING MACHINE:

Description:

The shear is mechanically driven and provided with a fixed blade and vertically

moving top blade. The drive is by electric motor via v-belts and fly wheel. By the

switch able friction clutch the continuously rotating fly wheel can be connected

with the toothed gear. The blade slide with the top blade is driven by the gear via

crank shaft and connecting rod. With the clutch disengaged the toothed gear is

connected with shear frame by a single disc brake. The blade slide moves in the

re-adjustable guides in the machine frame.

The machine frame consists of mainly two steel plates and the blade frame from

cast steel which accommodates the bottom blade and the down holders. Top blade

and bottom blade are mounted in special blade accommodations from cast steel

which holds the contact surfaces between machine and blade no wear on frame &

blade slide is ensured.

The down holder is arranged in the front of the shear over the bottom blade. The

down holder stroke is made by means of a wedge shaped sliding member whichdriving motion is taken off by the eccentric shaft. The down holder seats on the

cutting material prior to cutting and clamp during the total cutting operation. The

height for adaptation to the cross section is adjusted by means of a spindle gear.

The required cutting gap between top & bottom blades can be achieved by the


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Specifications: horizontal displacement of the bottom blade accommodations by

means of a wedge.

Operation:

The billets are placed in the cradle in bundles or separately up to 10tons. It is important that the cradle must be completely lowered to avoid damages in

case of hard placing.

An orderly and quantitatively regulated transfer of billets is performed by

lifting the cradle until the first billets are moved into the horizontally moved chute.

If the billets are disorderly moved on to the chute, it can be lifted until the billets are

arranged & ejector is adjusted.

If the cradle is lowered completely the ejector takes the bottom billet and

ejects it. Then the billet in chute moves up to the required length stop regulated

manually and clutch is engaged which cuts the billet into required length. Then theclutch is disengaged.

The forged jobs are dispatched to the customers after heat treatment is done.


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STEEL STRUCTURAL SHOP

In sss, the structural work and mainly fabrication work of steel is done. The

repairs of huge parts are also done. When used as industrial term, fabrication applies

to the building of machine, structures and other equipment, by cutting, shaping andassembling components made from raw materials.

Fabrication (steel structural) shop concentrated on the metal

preparation, welding and assembling aspects.

INPUTS:Sheets of various sizes, plates angles, channels, beams for fabrication

Of jobs.

PRODUCTION & SERVICES:All types of fabrication jobs, repair of slag pots of

SMS, Mfg. And repair of punishes for SMS, Mfg. Of scrap boxes for SMS for sinter

Plant, hot metal ladle for SMS, 500 meters launder for SMS, mfg. of KAMAG

Body for FMD. Repairing of buckets for LMMM, WRM. The annual production of

Fabricated structures are about 4,500 tones and the input consisting of sheets,

Plates, channels, angles, beams, etc. are about 5,100 T.

For marking, cutting to size, forming and bending, guillotine

Shear, circular saw plate bender, gas cutting unit etc. are provided, for welding

Transformer, automatic and semi-automatic machines and submerged arc

Welding machines are provided. Painting is carried out partly with help of spray

Guns and partly by hand .Wire brush, spray guns etc. are provided. A

maintenance

Section equipped with lathe, shaper, drill etc. are provided for running

Repair of shop equipment.

DETAILS OF SHOP:

Capacity: annual production is 4500 tones and material needed is 5100 tones.

Activities and work root:

Marking the material on stock

Cutting to prepare material for object

Assembling various parts or plates prepared for an object

Welding the assembled parts to join them

Inspection for the defects

Dispatching to customer after ensuring no defects.


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pg. 41

Welding techniques used in this shop are:

Arc welding

Metal in earth gas welding Thermite welding

Maintenance of stores:

A store is maintained for the new materials, spare parts and tools etc.

Raw materials for sss:

Channels

Sheets

Plates

Beams

Billets

AnglesThe raw materials are stored in open bay of the shop.

Major and regular jobs:

Hot metal ladle (BF)

Tundishes, Slag pot (SMS)

Coke bucket (Coke ovens)

Cones (SP)

Ducts (CRMP)

Rakes (Mills)

Hooks (for cranes)

Equipment in sss:

Shearing machine

Bending machine

Hydraulic press

Combination shearing machine

Radial drilling machine

CNC gas cutting machine


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pg. 42

Tool room

This equipment is located in material preparation bay in shop.

In material preparation bay the metal sheets and plates of required

dimensions are prepared by making and cutting on the various machines.

Marking is done in required profile by developing the surfaces of final

shape of the object using micrometer, steel rule, compass etc tools.

After marking, material will be cut and shaped. The operation of cutting

may be in the form of shearing, bending, punching, pressing, punching,

notching etc.

SHEARING MACHINE:

Shearing (metalworking):

Shearing is a metalworking process which cuts stock without the formation of

chips or the use of burning or melting. If the cutting blades are straight the

process is called shearing; if the cutting blades are curved then they are

shearing-type operations. The most commonly sheared materials are in the

form of sheet metal or plates; however rods can also be sheared. Shearing-

type operations include: blanking, piercing, roll slitting, and trimming.

Principle and working:

A punch (or moving blade) is used to push the work piece against the die (or

fixed blade), which is fixed. Usually the clearance between the two is 5 to

10% of the thickness of the material, but dependent on the material.

Clearance is defined as the separation between the blades, measured at the

point where the cutting action takes place and perpendicular to the direction

of blade movement. It affects the finish of the cut (burr) and the machine's

power consumption.

This causes the material to experience highly localized shear stresses between

the punch and die.

The fracture will begin at the weakest point and progress to the next weakest

point until the entire work piece has been sheared; this causes the rough edge.


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The material will then fail when the punch has moved 15 to 60% the thickness

of the material, because the shear stresses are greater than the shear strength

of the material and the remainder of the material is torn.

The rough edge can be reduced if the work piece is clamped from the top with

a die cushion. Above a certain pressure the fracture zone can be completely

eliminated. However, the sheared edge of the work piece will usually

experience work hardening and cracking. Two distinct sections can be seen

on a sheared work piece, the first part being plastic deformation and the

second being fractured.

Straight shearing:

Shearing machine

Straight shearing is done on sheet metal, coils, and plates. The machine usedis called a squaring shear, power shear, or guillotine.

The machine may be foot powered (or less commonly hand powered), or

mechanically powered. It works by first clamping the material with a ram.

A moving blade then comes down across a fixed blade to shear the material.

For larger shears the moving blade may be set on an angle or "rocked" in order

to shear the material progressively from one side to the other; this angle is

referred to as the shear angle.

This decreases the amount of force required, but increases the stroke. A 5

degree shear angle decreases the force by about 20%. The amount of energy

used is still the same.

The moving blade may also be inclined 0.5 to 2.5, this angle is called the

rake angle, to keep the material from becoming wedged between the blades,

however it compromises the square ness of the edge.[3] As far as equipment


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is concerned, the machine consists of a shear table, work-holding device,

upper and lower blades, and a gauging device.

The shear table is the part of the machinery that the work piece rests on while

being sheared. The work-holding device is used to hold the work piece in

place and keep it from moving or buckling while under stress.

The upper and lower blades are the piece of machinery that actually do the

cutting, while the gauging device is used to ensure that the work piece is being

cut where it is supposed to be.

The design of press tools is an engineering compromise. A sharp edge,

strength and durability are ideal; however a sharp edge is not very strong or

durable so blades for metal work tend to be square-edged rather than knife-

edged.

Typical work piece materials include aluminum, brass, bronze, and mild steel

because of their outstanding shear ability ratings, however, stainless steel is

not used as much due to its tendencies to work-harden.

There are also other types of Geometrical Possibilities besides straight

shearing though: These include the Squaring Shear, the Angle Shear, the Bow-

Tie Shear and the Bar Shear. All of these have many different uses and are all

used pretty regularly in certain manufacturing fields.

Tool Materials:

Low alloy steel is used in low production of materials that range up to 1/4 in.

thick

High-carbon, high chromium steel is used in high production of materials that

also range up to 1/4 in. in thickness

Shock-resistant steel is used in materials that are equal to 1/4 in. thick or more

COMBINATION SHEARING MACHINE:


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pg. 45

It is a multi-purpose machine. It is completely mechanically operated. Five

types of operations can be done simultaneously on the machine.

These operations are:

2)

Punching: it is a purpose of making a desired hole by using a punch anddie ( 35, 32; sq. 28, 32 ;).

3) Notching: it is a process of cutting out the edges of the strip to obtain the

desired outer contour of the work piece (dimensions of blade:18018018).

4) Cropping: cutting the square bars and round bars (63, sq55).

5) Shearing: cutting stocks without formation of chips.

The machine consists of individual units for each operation having punches,

dies, blades which are necessary for the above operations.

The punching unit is located in the front of the machine. Shearing and

cropping units in the rear side and notching unit is in the middle of the

machine. At one side of the machine a fly wheel is located and connected to

motor to balance the machine and also drive all units. This machine is used

crank lever mechanism to drive. A gear train is mounted to fly wheel shaft

and all drives shafts. When the lever of unit is engaged to this gear train, that

unit is then starting working. All the units of this machine can be operated

simultaneously, thus it can be used for mass production.

BENDING MACHINE:

This is used to bend the plates or sheets in order to form into

cylindrical shape, conical shape and other curved shapes as well as to

straighten the curved and abstracted plates or sheets and made them flat.

Principle:


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pg. 46

The plates are fed between top roller and bottom rollers and pressure is

given from bottom to top of the plate and plate is fed to and fro so that it is

gradually bent into required shape.

Construction and operation:

Bending and straightening machine consists of five rollers one is

mounted at center of upper side of machine and four rollers are inserted in

radial slots at bottom, can be lowered and raised radically. A reversible

electric motor is connected to each bottom roller to drive them and the main

motor is connected to top roller.

The plate is placed on the bottom rollers ensuring that the edges of the

plate and rollers are parallel. When the machine is switched on the rollers startrotating and slowly raised. Then the plate starts bending about the top roller.

At the same time the plate is fed to and fro by reversing the motor and bending

progresses to the final shape.

For conical sections the plate is bent in different sections a parted equal

space.

Bending has to overcome both tensile and compressive stresses. When

bending is done the residual stresses make it spring back towards its original

position, therefore it should be over bend.

For straightening process first, two alternate rollers are raised and then

the passed through remaining bottom rollers. The raised rollers are lowered

against plate, and then the plate is straightened.

The capacity of the machine is 25 mm thick ness and 2 m width of the

plate.

HYDRAULIC PRESS:

It is used to pressing large castings. The ram is moved by the pressure of the

fluid. Oil is mostly used fluid for this press. The pressure of oil is increased

by pump and is transmitted to the cylinder in order to lift the ram of or to force

the ram downwards. The capacity of machine is 200 T.


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CNC GAS CUTTING MACHINE:

CNC:In modern CNC systems, end-to-end component design is highly automated

using CAD/CAM programs. The programs produce a computer file that is

interpreted to extract the commands needed to operate a particular cutting

operation.

The movement of the tool resulted in varying forces on the controls that would

mean a linear output would not result in linear motion of the tool. The key

development in this area was the introduction of the servo, which produced

highly accurate measurement information. Attaching two servos togetherproduced a selsyn, where a remote servo's motions was accurately matched

by another. Using a variety of mechanical or electrical systems, the output of

the selsyn could be read to ensure proper movement had occurred.

MIT fit gears to the various hand wheel inputs and drove them withroller chainsconnected to motors, one for each of the machine's three axes (X,

Y, and Z). The associated controller consisted of five refrigerator-sized

cabinets that, together, were almost as large as the mill they were connected

to. Three of the cabinets contained the motor controllers, one controller foreach motor, the other two the digital reading system.[7]

The MIT design used standard 7-trackpunch tapefor input. Three of the tracks

were used to control the different axes of the machine, while the other fourencoded various control information.[8]The tape was read in a cabinet that

also housed sixrelay-basedhardware registers,two for each axis. With every

read operation the previously read point was copied into the "starting point"

register, and the newly read one into the "ending point".[8]The tape was readcontinually and the number in the register increased until a "stop" instruction,

four holes in a line, was encountered.

The final cabinet held a clock that sent pulses through the registers, compared

them, and generated output pulses that interpolated between the points. Thepulses are sent into a summing register in the motor controllers, counting up

by the number of pulses every time they were received. The summing registers
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were connected to adigital to analog converterthat output increasing powerto the motors.

Once the second point was reached the pulses from the clock would stop, andthe motors would eventually drive the mill to the encoded position. The speed

of the cut by selecting points that was closer together for slow movements, orfurther apart for rapid ones.

The system was terribly complex, including 250vacuum tubes,175 relays andnumerous moving parts, reducing its reliability in a production setting. Curves

are as easy to cut as straight lines, complex 3-D structures are relatively easy

to produce, and the number of machining steps that required human action hasbeen dramatically reduced.

The standard "G-code" was adapted for CNC use. In turn, G-code wassupplanted by STEP-NC,a system that was deliberately designed for CNC,rather than grown from an existing plotter standard.

G-Code, or preparatory code or function, are functions in the Numerical

controlprogramming language.The G-codes are the codes that position the

tool and do the actual work, as opposed to M-codes, that manages the

machine; T for tool-related codes. S and F are tool-Speed and tool-Feed, and

finally D-codes for tool compensation.

Partial list of M-Codes

M00=Program Stop (non-optional), M01=Optional Stop, machine will only

stop if operator selects this option, M02=End of Program, M03=Spindle on

(CW rotation), M04=Spindle on (CCW rotation), M05=Spindle Stop,

M06=Tool Change, M07=Coolant on (flood), M08=Coolant on (mist),

M09=Coolant off, M10=Pallet clamp on, M11=Pallet clamp off,

M30=End of program/rewind tape (may still be required for older CNC

machines).

Common G Codes:

G00 Rapid positioning; G01 Linear interpolation; G02 CW circular

interpolation; G03 CCW circular interpolation; G12 CW Circle Cutting; G13

CCW Circle Cutting; G17 X-Y plane selection; G18 X-Z plane selection; G19
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pg. 49

Y-Z plane selection; G20 Programming in inches; G21 Programming in mm;

G90 Absolute programming; G91 Incremental programming;

CNC gas cutting machines main parts are:

Control panel Frame

Cutting torch

Nozzles

Gas cylinders

Control panelis the main part of the CNC gas cutting machine which

consists of various buttons to enter the data into the machine. It consists of

various controls to regulate the speed of the torch to perform operation.

Frame includes the bed for placing the sheet and mild steel framewhich holds cutting torch and moves according to the given program to cut

the required structure.

Torchis made of brass to with stand high temperatures. It has two ends.

To the one end nozzle is fixed and the other end has the provision to

connect two hoses for oxygen and acetylene.

Nozzlein the part of the torch where flame comes out and the cutting

takes place. Various sizes of nozzles are provided for various thicknesses.

Gas cylinders of oxygen and acetylene are used for gas cutting. In

this machine cutting is carried out by using oxy- acetylene.

RADIAL DRILLING MACHINE:

Radial drilling is used for drilling heavy works and especially for thejobs where high degree of accuracy is required. Its main parts are:

Base

Column

Radial arm

Drill head

SpindleBASE is a rigid cast iron casting which is designed to support column and table. It

also contains fluid reservoir for coolant &for lubrication.

COLUMN is mounted vertically on the base and supports radial arm. It also houses

drive mechanism for spindle.

RADIAL ARM is supported by column and rotates 360o to provide easy drilling in


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pg. 50

heavier works.

DRILL HEAD moves on the guide ways of the radial arm and it houses spindle and

speed and feed.

SPINDLE is the main part which holds the drill and performs the operation. Both

parallel shank and taper shank drills are used in drilling. The standard taper of tapershank drill is called MORSE TAPER.

The prepared plates, sections in material preparation bay, they are transferred to

assembly may for assembling of various parts of a structure. The plates are welded

to make a required structure.

Welding is process of making a permanent joint by establishing inter atomic bonds

between two or more pieces of metal using heat or heat and pressure.

In SSS, three types of welding techniques are using. They are:

i. Arc welding

ii. MIG weldingiii. Thermite welding


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pg. 51

FOUNDRY SHOP

Foundry work deals with manufacture of products from molten metal and obtained

products are called castings.

The iron and steel foundry at VSP produces metal castingsMeant for internal uses at different departments like SMS, sinter plant,

continuous Casting, blast furnace, coke ovens etc. The raw materials for the

foundry are blast furnace pig iron and steel scrap.

This foundry has excellent facilities to produce Quality castings economically on a

large scale. The VSP foundry is mainly a captive Foundry because the castings

produced by it are used only in VSP and is jobbing in Nature as variety of castings

varying in chemistry and weight are being made. Recently started executing

outside orders for special steel ingots.

SEQUENCE OPERATIONS:

1. Pattern Making

2. Mould and Core making3. Melting and Pouring

4. Fettling5. Inspection

PATTERN MAKING:

Pattern is the replica or full size model of castings to be made. It gives its

shape to the mould cavity in which the molten metal solidifies to that desired form

and size.

PATTERN ALLOWANCES:

A pattern differs from the casting dimensions. The size of pattern is slightly larger

than the finished casting by an amount called allowance.

The allowances given to pattern are:

1) Shrinkage allowance:


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When molten liquid metal solidifies, the contraction or shrinkage will takes

place i.e. reduces its original size. Therefore the pattern is made larger or

oversized than the required casting dimensions. The correction for this is

expressed as a ratio.

2)

Machining allowance:After casting is made machining is done in order to get smooth and clean

finishing. Therefore the excess dimensions are given to the pattern.

3) Draft allowance:

When a pattern is removed from a mould the tendency to tear away the edges

of the mould is reduced if vertical surfaces of the pattern are tapered inwards.

4)Rapping allowance:

Due to rapping of the pattern in the mould, the size of the mould cavityincreases slightly. Therefore shake or rapping allowances shall be given

to pattern making it smaller to compensate for rapping.

Types of patterns:

1) Solid pattern:In this type one side is made flat which serves as a parting surface. The

mould cavity will be entirely in the drag.

2) Split pattern:It is used for intricate and complex shaped casting. In two piece pattern one

part producing the mould in drag and the other in cope. In three piece pattern

molding box is with these parts. Center one is cheek box and remaining are

same.

3) Gated pattern:The pattern which includes gates and riser for producing castings are called

gated pattern.

4) Sweep pattern:It is a template made of wood or metal revolving around a fixed axis in

mould, shapes the sand to desired contour.

5) Cope and Drag pattern:This pattern is made up of two halves, which are mounted on different

plates. Cope and drag parts are made separately and then assembled.


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pg. 53

6) Skelton pattern:It is used for making large castings in small number. This is a wooden frame

out lining the shape of the casting. The frame is filled with loam sand and

rammed.

7) Segmental pattern:It is form of a segment and used for molding circular objects such as rings,

wheel rims etc. This pattern revolves about center.

PATTERN MATERIALS:

1) Wood

2)

Metal3) Steel4) Thermo coal

5) Plaster of Paris

6) Ceramics

In foundry shop the castings are made that is necessary to VSPs needs.

The sand is used for molding as it has high thermal shock absorption.

Various types of sands used in Foundry are:

Green sand: Molding sand containing moisture is called green sand. Itconsists of silica, clay, water (5%). It can be reused by reconditioning.

Dry sand: Sand free from moisture is dry sand, which is used for largecastings as it having high strength...

Parting sand: It is used to prevent the moulding sand from sticking tosurfaces. It is free from clay.

Core sand: It is silicon sand mixed with organic compound like oils, resins etc.It has high refractive ness used for core making.

Silica sand: It consists of 98% to 90% silica mixed with clay. It is mixed withcoal powder and used for CO2 moulding process.


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MOULDING PROCESSES:

According to method:

Bench moulding: In this moulding flasks are kept on bench used for small castings.

Flour moulding: The mould is made on flour. It does not required cope box.

Pit moulding: Mould is made in pit and dug in flour. It acts as drag box and the cope

box is used separately.

According to material:

CO2 process:

In this process silica sand is mixed with a small amount of sodium silicate and is

placed in moulding box and rammed. After moulding Co2 gas at certain pressure is

flowed through mould by vent holes. As the result of chemical reaction between

CO2 and sodium silicate, sodium carbonate is formed. Therefore the sand is made

harder and ready for pouring. This sand can be used only once and not suitable for

reconditioning.

Green sand moulding:

It uses moist sand in which clay will be added to with stand the forces. Drying is not

necessary and molten metal is poured as soon as the mould is prepared.

MELTING:

Melting is a process of changing the solid state of iron or steel to liquid state. The

molten metal is poured into the mould and then solidifies in order to get required

casting.

The furnaces used in this shop are:

1) Direct Electric Arc Furnace2) Induction Furnace

Direct Electric Arc Furnace:-

This is used to melt steel and other metals.

Charge: Steel scrap, Limestone. Steel scrap is the metal which is used for casting

a

vizag steal plant in es& f

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