basic met ht sep 2009

7/28/2019 Basic Met Ht Sep 2009

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Crystal Structures- Body centered cubic (BCC)

- Face centered cubic (FCC)


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7


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723 C


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MICRO ALLOYING (Ti, Nb, V)

PEARLITE CONTENT (C, Mn)

ACCICULAR FERRITE (Tempering)

FINE GRAIN SIZE (Controlled rolling)

PRECIPITATION HARDENING (Cu)

METHODS OF STRENGTHENING


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ASME Material Specification

Section II, Part A

Wrought, castings & forgings

Ferrous : Cast iron, carbon steels

: Heat resisting (Cr-Mo)

steels: Stainless steels

Structural & Pressure vessels


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Test

Certificate


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MANGANESE ALUMINIUM

CARBON CHROMIUM

NICKEL TITANIUM

COPPER VANADIUM

NIOBIUM MOLYBDENUM

NITROGEN BORON

ALLOYING ELEMENTS


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PROPERTIES REQUIRED IN STEELS

EXCELLENT TOUGHNESS(Fine grains, Bainite)

GOOD WELDABILITY

RESISTANCE TO BRITTLE FRACTURE

DEFORMABILITY (GOOD DUCTILITY )


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CGHAZ


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Microstructure constituents in steels

Ferrite - low carbon solubility : BCC

Pearlite - combination of ferrite and cementite

Austenite - FCC

Bainite : Iron carbide with good toughness

Martensite - Rapidly cooled by quenching

Untempered martensite is the hardest and mostbrittle of the microstructures


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Multi pass weld beads


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Multi pass weld beads


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Macro Beadof SMAW E430

Macro Beadof E430 Nb


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MacroUnpulsed weld

Macro

Pulsed weld


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Process vessels (ALUMINA

PLANT-HINDALCO,ZUARI AGRO)

PetrochemicalVessels (KRL, MRPL)


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View of LPG Gas pipeline


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Pin Hole, Dent in Crack


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Visible Cracks

Cracks in a pipe


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Cracks in a pipe

MICROSTRUCTURE : F + P


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MICROSTRUCTURE : F + P

BM Lamination


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BM Lamination

Bend test : Opening


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Bend test : Opening


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SEM Study Ductile Fracture


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SEM Study Ductile Fracture


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Problems

Hydrogen cracking

Solidification cracking

Lamellar tearing


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Hydrogen induced crack

Fillet and butt welds HAZ

Fillet and butt welds


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Preheat

Carbon equivalent

Thickness of the base metal

Diffusible hydrogen content

Restraint

Welding process, consumable &

Heat input

Preheat


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Preheat

No welding on the base metal covered with ice

No welding shall be done at or below - 18 deg C

Raise the base metal temperature to min. 16 C

when the ambient temp is 0 to - 18 deg c

Preheat temperature shall be measured at a

distance of 2t or 4 which is higher

Preheat temperature shall be maintained during

welding

Welding cycle for X20CrMoV12 1


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Welding cycle for X20CrMoV12 1

FRICTION WELD


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FRICTION WELD

BEND SAMPLES

Failed sample

Passed sampleAfter PWHT


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Hydro-turbine components

A lternat ives to PWHT

Select ion o f su itab le electrodes

Weld bead techniques for in-si tu

repair

Peening studies, Half bead / temper bead

f


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Preheat Range for welding cast ironTYPE MICROSTRUCTURE PREHEAT C

GRAY IRON 20 - 300

MALLEABLE FERRITIC 20 - 150

MALLEABLE PEARLITIC 20 - 300

DUCTILE FERRITIC 20 -150

DUCTILE PEARLITIC 20 - 300


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FORMING, WELDING and HEAT TREATENT

Cold working (forming) -

Temperature less than 590CCold bending, Squeezing, Swaging

Hot working (forming) - Temperature more than 590C

Hot working : Hot bending, Hot swaging, Hot correction,

Welding


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S


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Steel grades :

Carbon steel :

Grades - P1 Group 1 and 2,

SA 210 Grade C, A1

SA 192, SA 178 Grade A and C

SA299, SA 106 grade B, C

SA 234 grade WPB, WBC,

SA 515 Grade 60, Grade 70


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Low Alloy Steel : Grades

P3 Group 1, SA 209 T1,

P3 Group 2 T2,

SA 234 grade 11, 22

P4 Group 1 SA 213 T11,

P5 Group 1 SA 213 T22 (Tube)

- SA 335 P12, P22, P91 (Pipes)

DIN 12X1Mo

P5 Group 2 SA 213 T91


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Austenitic Stainless steel :

P8 Group 1 SA 213 TP 304H, 347H

Heat Treatment Techniques :

Stress relieving for bends and welds

: 600 760C, +/- 15C

(PWHT- Post-weld Heat Treatment)


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Normalizing range : 950 1070C

Tempering range : 730- 760C

Solution annealing range : 1040 1150C


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Stress Relieving cycle for carbon steel


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Normalising cycle for low alloy steel


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Solution annealing cycle for austenitic stainless steel

basic met ht sep 2009

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