heat treatment training manual.ppt
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HEATTREATMENTTRAINING MANUAL MAY-2001 (REV.-0)
* This Manual is compiled by
Mr K S Rao (QA), Mr S P Ghiya (Inspection ) and Mr N M Bodalia (M FS)
Under the guidance of
Mr P D Lohidakshan (Weld Engg & Prod Engg )HEAT TREATMENT MANUAL
* INDEX TOPIC PAGE NO. 1 . INTRODUCTION ON HEAT TREATMENT 4- 24 2 . FURNACE PARTS AND ATTACHMENTS 25- 37 3. STD. OPERATING PROCEDURES(HFS)38- 47 4 . STD. OPERATING PROCEDURES(PFS)48- 56 5 . STD. OPERATING PROCEDURES(MFS)57-69 6 . STANDARD PRACTICES FOR LSR70-74 7 . GOOD ENGINEERING PRACTICE 75-88 8 . CODE EXTRACT(REFERENCE ONLY) 89- 101 9 . ANNEXURES 102- 118
*General Only qualified supervisors and operators including
LSR operators shall be authorised to operate furnace. A list of qualified personnel shall be prepared by QA
and published periodically. Thjs manual is prepared on the basis of experience
and feedback, taken from various personnel. This manual is for reference only.
*HEAT TREATMENTWHAT IS HEAT TREATMENT ?WHY IS IT REQUIRED ?TYPES OF HEAT TREATMENTHEAT TREATMENT AT HZW
*WHAT IS HEAT TREATMENTMATERIALS TREATED BY APPLICATION OF HEAT NORMALLY DONE IN SOLID STATEVARIOUS SOURCES OF HEAT PARAMETERS ARE HEATING RATE,SOAKING TEMP,SOAKING TIME,COOLING RATE AND COOLING MEDIA
*WHY IS IT REQUIRED ?TO ENHANCE MATERIAL PROPERTIES / EASE IN FABRICATION BY CHANGINGStrength,Improve corrosion resistanceToughness/DuctilityHardness,Dimensional stability etcRemove diffusible hydrogen to avoid hydrogen crackingCARRIED OUT IN FABRICATION INDUSTRIES ,STEEL PLANTS, FOUNDRY, FORGING SHOPS etc..
page of 108*
*MATERIALS HEAT TREATED
METALS & ALLOYS SINGLE PHASE MULTIPHASE ALLOYSSingle Phase : Copper Nickel Multiphase : Steels-LAS,QT METALS (Single phase ) Titanium,Al,Ni,Cu etc..
*MATERIALS HEAT TREATEDCRITERIACOLD WORKED to NORMALAll materialsUNEQUILIBRIUM PHASES to EQUILIBRIUM:(Stabilise Microstructure & Phases)Stainless Steels ,Maraging SteelsSTRESSED to UNSTRESEDAll MaterialsCREATION OF UNEQUILIBRIUM CONDITIONSSteels
*MATERIALS HEAT TREATEDMATERIALS CATEGORY
C-Mn , C-Mo , Cr-Mo , Ni -Steels, QTStainless Steels-Austanitic.MartensiticSteels enhanced by Heat Treatments Non Ferrous Materials; Titanium alloys, Aluminum alloys
*TYPES OF HEAT TREATMENTNORMALIZINGANNEALINGSTRESS RELIEVING SOLUTION ANNEALING-Mainly SSHARDENINGTEMPERINGAGING
*IRON CARBON DIAGRAM
*Iron Carbon DiagramPortion related to Heat Treatment
*NORMALIZING The steel is heated to 40 C above the upper critical temperature(910 c) followed by cooling in the still air.
Normalizing is done to achieve the following : To get Uniform structure and reduce chemical gradients To change Mechanical properties,UTS,YSHardness Impact properties To refine the grains
*ANNEALING In this process, the steel is heated from 10 to 50C above the upper critical temperature(910c) and held for the desired length of time; followed by very slow cooling in the furnace
Annealing is done to achieve following :to soften the steel and improve ductilityto relieve internal stresses caused by previous treatment
*SOLUTION ANNEALING In Stainless steels , it is heated to 1050C or above ,and held for the desired time; followed by quenching/blowing the air(cooling to room temperature within few minutes). Solution annealing is done on stainless steel and non ferrous alloys to achieve following:To soften the materialTo dissolve carbide precipitation formed at grain boundaries during manufacturing processTo improve Corrosion Resistance
*AGING The Material is heated to a certain temperature, and held for the desired time; followed by normally for precipitation hardened alloys or cooling in air Aging is done on materials susceptible for aging characteristics : Maraging Steels Normally increase in strength To Improve Toughness/Ductile-brittle transition temp.
*AGINGMaraging Steels M250Temperature : 485 C Normally 3 Hrs 15 mtsHeating Rate : 200 C per hr per inchCooling Rate : Cool in Air / Quench in water
*STRESS RELIEVING The steel is heated to a temperature below or close to the lower critical point, followed by desired rate of cooling and there is no change in grain structure.Stress relieving is done to achieve following : To reduce Internal Stresses (residual Stresses)To soften the steel partially To improve ductile-brrittle transition temp. and equalize impact values
*STRESS RELIEVINGC-Mn , C-Mo , Cr-Mo (< 2% Cr)C - Mn Steels , C - Mo Steels,Cr-Mo Steels SA 515Gr 70 , SA204GrA, SA387GR11CL1Temperature : 593 C MinNormally 600 - 640 C,650-690 C Time : 15 minutes minTime : 1 hr / inchHeating Rate : 200 C per hr per inchCooling Rate : 260 C per hr per inch
*Cr-Mo SteelsCr - Mo Steels (Cr >2%)SA 335P22 ,SA335P5Temperature : 676 C MinNormally 680 - 700 C 2.25Cr 704 - 720 C 5 Cr Time : 15 mts minTime : 1 hr / inchHeating Rate : 200 C per hr per inchCooling Rate : 260 C per hr per inch
*Ni -SteelsNickel Steels : 1,2,3% Ni SA 203 GrA ,DTemperature : 593 C MinNormally 600 - 640 C,650-690 C Time : 60 mts minTime : 1 hr / inchHeating Rate : 200 C per hr per inchCooling Rate : 260 C per hr per inch
*Steels enhanced by Heat Treatments Q&T Steels :9.5% Ni Steels , SA 517 Gr ETemperature : 538 C TypNormally < 600 C Time : Minimum 15 minutes to 2 HrTime : 1 hr / inchHeating Rate : 200 C per hr per inchCooling Rate : 260 C per hr per inch
*FURNACE PARTS AND
*LAYOUT OF A TYPICAL FURNACE (Electrical or Gas fired )
*THERMOCOUPLESPRINCIPLE OF A THERMOCOUPLE
TYPES OF THERMOCOUPLES BEING USED IN HZW
*PRINCIPLE OF THERMOCOUPLEThe basic principle of thermoelectric thermometry is that a thermocouple develops an emf which is a function of the difference in temperature of its measuring junction & reference junction. If the temperature of reference junction is known, the temperature of the measuring junction can be determined by measuring the emf generated in the circuit.
*THERMOCOUPLE MATERIAL REQUIREMENT1. High coefficient of thermal emf.2. Continuously increasing relation of emf to temperature over a long range.3. Freedom from phase changes or other phenomenon giving rise to discontinuity in temperature emf relationships.4. Resistance to oxidation, corrosion and contamination.5. Homogeneity and reproducibility to fit an establish temperature & emf relationship.SPEED OF RESPONSE MAY BE IMPROVED AND RADIATION & CONDUCTION ERRORS MAY BE REDUCED BY THE USE OF SMALL DIAMETER THERMOCOUPLES.
*TYPES OF THERMOCOUPLE BEING USED IN HZW K type : Material : Chromel + Alumel Nickel based ( 10 %Cr ) + ( 2 % Al ) Properties : Non-Magnetic + MagneticIn this type of thermocouple, the wires are joined at one end only to form a point-type temperature sensor. Instrumentation converts the millivolt signal to related temperature.
*TYPES OF THERMOCOUPLE BEING USED IN HZW contd... K type : Dia : 2.5 mm 0. 7 mmInsulation Bare(ceramic)Refractory coatedAttachmentMechCapacitorUsability ReusableDisposableLocationPIT F/cexcept PIT F/cColor -Red & Yellow
recorderpidCompensating cableThermocouple wireWelded junctionCONSTRUCTION OF A K TYPE THERMOCOUPLEAccuracy : 0.75%Red ColorBlue ColorWhite ColorWhite/yellow+Ve-Ve-Ve+VeWhite ColorWhite/yellowBlue ColorRed Color
*S TYPE THERMOCOUPLE S TYPE THERMOCOUPLE ARE THE STANDARD
IT IS USED FOR CALIBRATING K Type
MATERIAL OF CONSTRUCTION
90% PLATINUM + 10% RHODIUM PLATINUM
OXIDATION RESISTANCE , SO MORE LIFE .
Accuracy : 0.25 %
*ISSUE METHODOLOGYFor DISPOSAL TYPE
Users will send their requirement of thermocouple
through Consumable slip ( mentioning HTR No ) to QA
QA shall issue the same .
QA shall issue identification sticker duly attached
Users shall ensure availability of identification sticker
on unused wire . See Annexure-12 for further details
*COMPENSATING CABLECOMPENSATING CABLE IS DEFINED AS A PAIR OF WIRES HAVING SUCH EMF TEMPERATURE CHARACTERISTICS RELATED TO THE THERMOCOUPLE WITH WHICH THE WIRES ARE INTENDED TO BE USED, THAT WHEN PROPERLY CONNECTED TO THERMOCOUPLE THE EFFECTIVE REFERENCE JUNCTION IS IN EFFECT TRANSFERRED TO THE OTHER END OF THE WIRES.
MATERIAL ==> +ve COPPER ( white ) -ve COPPER NICKEL (blue ) for K TYPE .
See Annexure-9 (Annexure Page 1-4) for further details
*P.I.D.PID = PROPORTIONAL INTEGRAL DERIVATIVE PID FUNCTIONS BOTH AS PROGRAMMER AND
CONTROLLER PID CONTROLLER CAN BE ZONE WISE PROGRAMME IS MADE IN SEGMENTS AS PER
DIFFERENT STAGES OF HEAT TREATMENT DIGITAL DISPLAY IS AVAILABLE FOR PROGRAMME