Weldability pc
JithuJohn3
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Jul 23, 2014
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About This Presentation
WELD
Slide Content
Metals & Their Weldability
Pallav Chattopadhyay
Pallav Chattopadhyay
Weldability
• No universally accepted meaning
• AWS Definition :
“The capacity of a metal to be welded under the
fabrication conditions imposed, into a specific,
suitably designed structure, and to perform
satisfactorily in the intended service”
• No universally accepted meaning
• AWS Definition :
“The capacity of a metal to be welded under the
fabrication conditions imposed, into a specific,
suitably designed structure, and to perform
satisfactorily in the intended service”
Weldability
• C-Mn Steel
• Low Alloy Steel (Cr-Mo / Cr-Mo-V steel)
• Quenched & tempered Steel
• Stainless Steel
• Ni Alloys
• Al Alloys
• Ti Alloys
• C-Mn Steel
• Low Alloy Steel (Cr-Mo / Cr-Mo-V steel)
• Quenched & tempered Steel
• Stainless Steel
• Ni Alloys
• Al Alloys
• Ti Alloys
Weldability of C-Mn Steel
• C – 0.15% max, Mn- 1.65%max, Cu & Si- 0.60% max
• SA516 Gr60 / 70, SA537 Cl.1, SA 106 Gr.B, SA 105
• CE (IIW) = C + (Mn/6) + [(Cr+Mo+V)/5]+ [(Ni+Cu)/15]
• Excellent weldability upto CE = 0.45
• Comparatively less susceptible to Hydrogen cracking
• Preheat / PWHT called for only higher thk (>30mm)
• Suitable for all type of Arc & other Welding processes
• Weld soundness is not problem with Killed steels
• C – 0.15% max, Mn- 1.65%max, Cu & Si- 0.60% max
• SA516 Gr60 / 70, SA537 Cl.1, SA 106 Gr.B, SA 105
• CE (IIW) = C + (Mn/6) + [(Cr+Mo+V)/5]+ [(Ni+Cu)/15]
• Excellent weldability upto CE = 0.45
• Comparatively less susceptible to Hydrogen cracking
• Preheat / PWHT called for only higher thk (>30mm)
• Suitable for all type of Arc & other Welding processes
• Weld soundness is not problem with Killed steels
Weldability of C-Mn Steel
Weldability of C-Mn Steel
Typical CCT Diagram
Typical CCT Diagram
Weldability of C-Mn Steel
• SMAW
–Matching electrodes available for chemistry / strength level
–Low Hydrogen electrodes (E7018) reduce chance of
Hydrogen cracking
–Baking & Storage of electrode – Moisture free
• GTAW / GMAW
–Suitable bare electrodes available like SMAW
–Electrodes with de-oxidizer preferred to reduce chance of
porosity (e.g. ER 70S-2)
–Argon based gas mixtures for GTAW
–CO2 / Argon-CO2 Mixture for GMAW
–Proper cleaning / packing / storage of Filler metal & good
quality Shielding gas required
• SMAW
–Matching electrodes available for chemistry / strength level
–Low Hydrogen electrodes (E7018) reduce chance of
Hydrogen cracking
–Baking & Storage of electrode – Moisture free
• GTAW / GMAW
–Suitable bare electrodes available like SMAW
–Electrodes with de-oxidizer preferred to reduce chance of
porosity (e.g. ER 70S-2)
–Argon based gas mixtures for GTAW
–CO2 / Argon-CO2 Mixture for GMAW
–Proper cleaning / packing / storage of Filler metal & good
quality Shielding gas required
Weldability of C-Mn Steel
• FCAW
–Self Shielded / Gas Shielded consumables available
–Shielding Gas – CO2 / CO2-Argon mixture (e.g. E71T-1)
–Normally low in Hydrogen level – baking not required
• SAW
–Solid (even Metal Cored wires) wire + Suitable Flux
–Fused / Agglomerated Flux (Mostly Neutral)
–Solid wire – Cu coated / Flux – requires Redrying
–Desired properties – As welded / With PWHT
• FCAW
–Self Shielded / Gas Shielded consumables available
–Shielding Gas – CO2 / CO2-Argon mixture (e.g. E71T-1)
–Normally low in Hydrogen level – baking not required
• SAW
–Solid (even Metal Cored wires) wire + Suitable Flux
–Fused / Agglomerated Flux (Mostly Neutral)
–Solid wire – Cu coated / Flux – requires Redrying
–Desired properties – As welded / With PWHT
Weldability of C-Mn Steel
• Other Welding Processes
–Electro Slag / Electro Gas Welding:
•Suitable Consumable available
•May require additional Heat Treatment as per Code
–Oxy Acetylene Welding:
•Suitable consumable available
•Slower than Arc Welding – Extensive heating of steel / slow
cooling
•Chance of imperfection more
• Other Welding Processes
–Electro Slag / Electro Gas Welding:
•Suitable Consumable available
•May require additional Heat Treatment as per Code
–Oxy Acetylene Welding:
•Suitable consumable available
•Slower than Arc Welding – Extensive heating of steel / slow
cooling
•Chance of imperfection more
Weldability of C-Mn Steel
• Other Welding Processes
–Resistance Welding:
•Spot/ Seam/ Flash / Upset welding possible
•Heating / Cooling rates higher
–Electron / Laser Beam Welding:
•Readily weldable
•Rapid Heating & Cooling rates – Smaller grains in Weld /
HAZ
•Fully Killed steel preferred
• Other Welding Processes
–Resistance Welding:
•Spot/ Seam/ Flash / Upset welding possible
•Heating / Cooling rates higher
–Electron / Laser Beam Welding:
•Readily weldable
•Rapid Heating & Cooling rates – Smaller grains in Weld /
HAZ
•Fully Killed steel preferred
Weldability of Cr-Mo / Cr-Mo-V Steel
•Cr : 0.5 ~ 9%, Mo : 0.5 ~ 1%, V : ~0.25% & C £ 0.20%
•Cr provides improved oxidation & corrosion resistance
•Mo provides better elevated temp properties
•Good weldability
•High hardenability (Most of them Air-hardenable)
•Rapid cooling from above Ac3 temperature (~900°C)® strength
, hardness , ductility & toughness ¯
•Requires Tempering (~650°C) to restore the properties
•PWHT at >680°C (Typical: 680-705°C) mandatory for all
thickness
•Cr : 0.5 ~ 9%, Mo : 0.5 ~ 1%, V : ~0.25% & C £ 0.20%
•Cr provides improved oxidation & corrosion resistance
•Mo provides better elevated temp properties
•Good weldability
•High hardenability (Most of them Air-hardenable)
•Rapid cooling from above Ac3 temperature (~900°C)® strength
, hardness , ductility & toughness ¯
•Requires Tempering (~650°C) to restore the properties
•PWHT at >680°C (Typical: 680-705°C) mandatory for all
thickness
Weldability of Cr-Mo / Cr-Mo-V Steel
SA 387
Gr - 11
CL - 2
SA 336
Gr - F11
CL - 2
SA 336
Gr - F11
CL - 3
SA 387
Gr - 22
CL - 2
SA 336
Gr- F22
CL- 3
SA 335
Gr - P5
SA 387
Gr - 5
CL - 2
SA 542
Type D
CL.4a
Product From. Plate ForgingsForgings Plate ForgingsSmls.pipePlate Plate
C, Max. 0.04 - 0.170.10 - 0.200.10 - 0.200.04 - 0.150.05 - 0.150.15 0.150.09 - 0.18
Mn, Max 0.35 - 0.730.30 - 0.800.30 - 0.800.25 - 0.660.30 - 0.600.30 - 0.600.25 - 0.660.25 - 0.66
Cr, Max. 0.94 - 1.561.00 - 1.501.00 - 1.501.88 - 2.622.00 - 2.504.00 - 6.003.90 - 6.101.08 - 2.62
Mo, Max. 0.40 - 0.700.45 - 0.650.45 - 0.650.85 - 1.150.90 - 1.100.45 - 0.650.40 - 0.700.85 - 1.15
V, Max. - - - - - - - 0.23 - 0.37
-
SA 387
Gr - 11
CL - 2
SA 336
Gr - F11
CL - 2
SA 336
Gr - F11
CL - 3
SA 387
Gr - 22
CL - 2
SA 336
Gr- F22
CL- 3
SA 335
Gr - P5
SA 387
Gr - 5
CL - 2
SA 542
Type D
CL.4a
Tensile strength (Min)
Ksi 75 - 100 70 - 95 75 - 10075 - 10075 - 100 60 75 - 10085 - 110
Mpa 515 - 690485 - 660515 - 690515 - 690515 - 690415 525 - 610585 - 760
Yield strength (Min)
Ksi 45 40,000 45,000 45 45 30 45 60
Mpa 310 275 310 310 310 205 310 415
Elongation in 8 inch
(200mm) min,%
18.00 - - - - - - -
Elongation in 2 inch
(50mm) min,%
22.00 20.00 18.00 18.00 19.00 - 18.00 18.00
Reduction of area,
min %
- 40 40 45.00 40.00 - 45.00 -
Chemical properties
Mechanical
properties
SA 387
Gr - 11
CL - 2
SA 336
Gr - F11
CL - 2
SA 336
Gr - F11
CL - 3
SA 387
Gr - 22
CL - 2
SA 336
Gr- F22
CL- 3
SA 335
Gr - P5
SA 387
Gr - 5
CL - 2
SA 542
Type D
CL.4a
Product From. Plate ForgingsForgings Plate ForgingsSmls.pipePlate Plate
C, Max. 0.04 - 0.170.10 - 0.200.10 - 0.200.04 - 0.150.05 - 0.150.15 0.150.09 - 0.18
Mn, Max 0.35 - 0.730.30 - 0.800.30 - 0.800.25 - 0.660.30 - 0.600.30 - 0.600.25 - 0.660.25 - 0.66
Cr, Max. 0.94 - 1.561.00 - 1.501.00 - 1.501.88 - 2.622.00 - 2.504.00 - 6.003.90 - 6.101.08 - 2.62
Mo, Max. 0.40 - 0.700.45 - 0.650.45 - 0.650.85 - 1.150.90 - 1.100.45 - 0.650.40 - 0.700.85 - 1.15
V, Max. - - - - - - - 0.23 - 0.37
-
SA 387
Gr - 11
CL - 2
SA 336
Gr - F11
CL - 2
SA 336
Gr - F11
CL - 3
SA 387
Gr - 22
CL - 2
SA 336
Gr- F22
CL- 3
SA 335
Gr - P5
SA 387
Gr - 5
CL - 2
SA 542
Type D
CL.4a
Tensile strength (Min)
Ksi 75 - 100 70 - 95 75 - 10075 - 10075 - 100 60 75 - 10085 - 110
Mpa 515 - 690485 - 660515 - 690515 - 690515 - 690415 525 - 610585 - 760
Yield strength (Min)
Ksi 45 40,000 45,000 45 45 30 45 60
Mpa 310 275 310 310 310 205 310 415
Elongation in 8 inch
(200mm) min,%
18.00 - - - - - - -
Elongation in 2 inch
(50mm) min,%
22.00 20.00 18.00 18.00 19.00 - 18.00 18.00
Reduction of area,
min %
- 40 40 45.00 40.00 - 45.00 -
Chemical properties
Mechanical
properties
Weldability of Cr-Mo / Cr-Mo-V Steel
•Highly susceptible to Hydrogen Induced Cracking / Cold
Cracking
•Use of Low Hydrogen consumables is must
•Control on welding Heat Input
•Appropriate Preheat (~125-200°C), De Hydrogenation
Treatment (300-400°C) and Intermediate Stress relieving (640-
660°C) mandatory to prevent cracking
•In between cooling to room temperature not allowed – followed
by DHT /ISR
•High Cr(>5%)-Mo/ Cr-MoV steel calls for Direct PWHT after
welding
•Highly susceptible to Hydrogen Induced Cracking / Cold
Cracking
•Use of Low Hydrogen consumables is must
•Control on welding Heat Input
•Appropriate Preheat (~125-200°C), De Hydrogenation
Treatment (300-400°C) and Intermediate Stress relieving (640-
660°C) mandatory to prevent cracking
•In between cooling to room temperature not allowed – followed
by DHT /ISR
•High Cr(>5%)-Mo/ Cr-MoV steel calls for Direct PWHT after
welding
Weldability of Cr-Mo / Cr-Mo-V Steel
•Susceptible to Temper Embrittlement while operating between
375-575°C
– Control tramp elements (P, Sn, Sb, As etc) in Base metal & Weld metal
(‘J’ factor & ‘X’ factor respectively)
– “J” Factor : (P+Sn) x (Mn+Si) x 10
4
£ 100
“X” Factor : (10P+5Sb+4Sn+As) / 100 £ 15 ppm
– Perform Step cooling treatment and measure shift in DBTT
•Susceptible to Temper Embrittlement while operating between
375-575°C
– Control tramp elements (P, Sn, Sb, As etc) in Base metal & Weld metal
(‘J’ factor & ‘X’ factor respectively)
– “J” Factor : (P+Sn) x (Mn+Si) x 10
4
£ 100
“X” Factor : (10P+5Sb+4Sn+As) / 100 £ 15 ppm
– Perform Step cooling treatment and measure shift in DBTT
. STEP COOLING HEAT TREATMENT
1hr (1) 15hr (1) 24hr (1) 60 hr (2) 100 hr (3)
STEP COOLING HEAT TREATMENT
COOLING RATE ( °C / Hr. )
Sr.No.
REQUIRED ACTUAL
(1) 5.6 (MAX.) 5.0
(2) 2.8 (MAX.) 2.5
(3) 27.8 (MAX.) 25
538°C
524°C 496°C
468°C
315°C air/
furnace
cooling
593°C
50 °C/hr
1hr (1) 15hr (1) 24hr (1) 60 hr (2) 100 hr (3)
STEP COOLING HEAT TREATMENT
COOLING RATE ( °C / Hr. )
Sr.No.
REQUIRED ACTUAL
(1) 5.6 (MAX.) 5.0
(2) 2.8 (MAX.) 2.5
(3) 27.8 (MAX.) 25
538°C
524°C 496°C
468°C
315°C air/
furnace
cooling
593°C
50 °C/hr
TEMPER EMBRITTLEMENT TEST
0
30
60
90
120
150
180
210
240
270
300
-50 -40 -30 -20 -10 0 10 20 30 40
TEMPERATURE(°C)
A
B
S
O
R
B
E
D
E
N
E
R
G
Y
(
J
)
MIN.PWHT AVG.TW1 MIN.PWHT+ SC AVG.TW2
54J
TT
54
= -27°C TT
54
SC= -22 °C
TEMPER EMBRITTLEMENT PARAMETER : TT
54
+ 3DTT
54
<10 °C
Where, DTT
54 =
TT
54
SC
-
TT
54
0
30
60
90
120
150
180
210
240
270
300
-50 -40 -30 -20 -10 0 10 20 30 40
TEMPERATURE(°C)
A
B
S
O
R
B
E
D
E
N
E
R
G
Y
(
J
)
MIN.PWHT AVG.TW1 MIN.PWHT+ SC AVG.TW2
54J
TT
54
= -27°C TT
54
SC= -22 °C
TEMPER EMBRITTLEMENT PARAMETER : TT
54
+ 3DTT
54
<10 °C
Where, DTT
54 =
TT
54
SC
-
TT
54
Weldability of Cr-Mo / Cr-Mo-V Steel
• Arc Welding Processes
–Suitable weld consumables available for all types of Arc
Welding processes
Consumable Table
SMAW GTAW SAW
1.25Cr-0.5Mo E 8018 B2ER 80S B2EB2 + Suitable Flux
2.25Cr-1Mo E 9015 B3ER 90S B3EB3 + Suitable Flux
2.25Cr-1Mo-0.25VE 9018 G ER 90S G Union S1CrMo 2V (Brand name)
5Cr-0.5Mo E 8018 B6ER 80S B6EB6 + Suitable Flux
9Cr-1Mo E 8018 B8ER 80S B8EB8 + Suitable Flux
9Cr-1Mo-0.25V E 9018 B9ER 90S B9EB9 + Suitable Flux
Weld Consumable
Steel
• Arc Welding Processes
–Suitable weld consumables available for all types of Arc
Welding processes
Consumable Table
SMAW GTAW SAW
1.25Cr-0.5Mo E 8018 B2ER 80S B2EB2 + Suitable Flux
2.25Cr-1Mo E 9015 B3ER 90S B3EB3 + Suitable Flux
2.25Cr-1Mo-0.25VE 9018 G ER 90S G Union S1CrMo 2V (Brand name)
5Cr-0.5Mo E 8018 B6ER 80S B6EB6 + Suitable Flux
9Cr-1Mo E 8018 B8ER 80S B8EB8 + Suitable Flux
9Cr-1Mo-0.25V E 9018 B9ER 90S B9EB9 + Suitable Flux
Weld Consumable
Steel
Weldability of Cr-Mo / Cr-Mo-V Steel
• Other Welding Processes
–Resistance Upset Welding:
•Sometimes used for Longitudinal seam welding of Cr-Mo pipes &
tubes
•Strip roll formed to shape – continuously welded to make Tubes
using high frequency AC and forging by pressure rolls
•High localized heat inputs and fast cooling rates – low ductility
•Sometimes PWHT performed in welding machine only
–Electro Slag Welding:
•Primarily used for ³3” thickness
•Filler wire same as SAW is used
•Large build-up of heat – automatic preheating + Stress relief
•Subsequent Annealing / Normalizing is mandatory
• Other Welding Processes
–Resistance Upset Welding:
•Sometimes used for Longitudinal seam welding of Cr-Mo pipes &
tubes
•Strip roll formed to shape – continuously welded to make Tubes
using high frequency AC and forging by pressure rolls
•High localized heat inputs and fast cooling rates – low ductility
•Sometimes PWHT performed in welding machine only
–Electro Slag Welding:
•Primarily used for ³3” thickness
•Filler wire same as SAW is used
•Large build-up of heat – automatic preheating + Stress relief
•Subsequent Annealing / Normalizing is mandatory
Weldability of Quenched & Tempered Steel
•Heat Treatment Condition: Quenched & Tempered
•High YS, UTS with good toughness, ductility &
weldability
•Alloy addition to achieve desired mechanical
properties – mainly Ni, Cr, Mo, Mn, V
•Welded structures normally don’t need PWHT except
Stress Relieving
•Heat Treatment Condition: Quenched & Tempered
•High YS, UTS with good toughness, ductility &
weldability
•Alloy addition to achieve desired mechanical
properties – mainly Ni, Cr, Mo, Mn, V
•Welded structures normally don’t need PWHT except
Stress Relieving
Weldability of Quenched & Tempered Steel
Typical Chemistry & Properties
CHEMICAL
COMPOSITION
SA 533
Gr - B
CL-3
SA 517
Gr. - F
SA 533
Gr - B
CL-1
SA 533
Gr - B
CL-2
HY-80
Product From. Plate Plate Plate
C, Max. 0.25 0.08-0.22 0.25 0.25
Mn, Max 1.07-1.620.55-1.101.07 - 1.621.07 - 1.62
Si, Max. 0.13-0.450.13-0.370.13 - 0.450.13 - 0.450.15-0.35
Cu, Max. - 0.12-0.53 - - 0.25
Ni, Max. 0.37-0.730.67-1.030.37 - 0.730.37 - 0.732.00-3.25
Cr, Max. - 0.36-0.69 - - 1.00-1.80
Mo, Max. 0.41-0.640.36-0.640.41 - 0.640.41 - 0.640.20-0.60
V, Max. - 0.02-0.09 - - 0.03
Cb, Max. - - - -
Boron, Max. - 0.005-0.006
N - -
SA 533
Gr - B
CL-3
SA 517
Gr. - F
SA 533
Gr - B
CL-1
SA 533
Gr - B
CL-2HY-80
Tensile strength (Min)
Ksi 100-125 105-135 80 - 10090 - 115
Mpa 690-860 725-930550 - 690620 - 795
Yield strength (Min)
Ksi 83 90 50 70 80
Mpa 570 620 345 485
Elongation in 8 inch
(200mm) min,%
- - - -
Elongation in 2 inch
(50mm) min,%
16.00 14.00 18.00 16.00
Mechanical
properties
Typical Chemistry & Properties
CHEMICAL
COMPOSITION
SA 533
Gr - B
CL-3
SA 517
Gr. - F
SA 533
Gr - B
CL-1
SA 533
Gr - B
CL-2
HY-80
Product From. Plate Plate Plate
C, Max. 0.25 0.08-0.22 0.25 0.25
Mn, Max 1.07-1.620.55-1.101.07 - 1.621.07 - 1.62
Si, Max. 0.13-0.450.13-0.370.13 - 0.450.13 - 0.450.15-0.35
Cu, Max. - 0.12-0.53 - - 0.25
Ni, Max. 0.37-0.730.67-1.030.37 - 0.730.37 - 0.732.00-3.25
Cr, Max. - 0.36-0.69 - - 1.00-1.80
Mo, Max. 0.41-0.640.36-0.640.41 - 0.640.41 - 0.640.20-0.60
V, Max. - 0.02-0.09 - - 0.03
Cb, Max. - - - -
Boron, Max. - 0.005-0.006
N - -
SA 533
Gr - B
CL-3
SA 517
Gr. - F
SA 533
Gr - B
CL-1
SA 533
Gr - B
CL-2HY-80
Tensile strength (Min)
Ksi 100-125 105-135 80 - 10090 - 115
Mpa 690-860 725-930550 - 690620 - 795
Yield strength (Min)
Ksi 83 90 50 70 80
Mpa 570 620 345 485
Elongation in 8 inch
(200mm) min,%
- - - -
Elongation in 2 inch
(50mm) min,%
16.00 14.00 18.00 16.00
Mechanical
properties
Weldability of Quenched & Tempered Steel
•Appropriate joint design (No Stress-raisers), good
workmanship & adequate Inspection checks are
MUST
•Preheat extremely critical – to be chosen carefully
•Excess preheat / Interpass temp– Slower coling rate –
re-austenitized zone near weld metal transform to
Ferrite + High C Martensite /Bainite
•Heat input needs to be controlled on lower side
•Excess heat input – Reduction in Strength, Toughness
•Appropriate joint design (No Stress-raisers), good
workmanship & adequate Inspection checks are
MUST
•Preheat extremely critical – to be chosen carefully
•Excess preheat / Interpass temp– Slower coling rate –
re-austenitized zone near weld metal transform to
Ferrite + High C Martensite /Bainite
•Heat input needs to be controlled on lower side
•Excess heat input – Reduction in Strength, Toughness
Weldability of Quenched & Tempered Steel
•All Arc Welding processes available
•Electro Slag / Electro Gas/ Multiple wire SAW requires
re-heat treatment due to high heat input
•EBW / LBW preferred
•Small stringer weld beads – good toughness
•Selection of weld consumable – based on mechanical
property requirement (many times non-matching
chemistry)
•Very sensitive to Hydrogen cracking – allows
extremely low level of moisture / Hydrogen in weld
metal (target: 2ml/100gm)
•All Arc Welding processes available
•Electro Slag / Electro Gas/ Multiple wire SAW requires
re-heat treatment due to high heat input
•EBW / LBW preferred
•Small stringer weld beads – good toughness
•Selection of weld consumable – based on mechanical
property requirement (many times non-matching
chemistry)
•Very sensitive to Hydrogen cracking – allows
extremely low level of moisture / Hydrogen in weld
metal (target: 2ml/100gm)
Weldability of Quenched & Tempered Steel
•Manual / Mechanized oxy fuel cutting allowed –
remove 2-3mm hardened zone by grinding
•Machine cutting preferred
•Arc gouging allowed – with less heat input
•Gas gouging not allowed
•Brazing allowed – but may require Q&T since brazing
temp is high
•Manual / Mechanized oxy fuel cutting allowed –
remove 2-3mm hardened zone by grinding
•Machine cutting preferred
•Arc gouging allowed – with less heat input
•Gas gouging not allowed
•Brazing allowed – but may require Q&T since brazing
temp is high
Weldability of Stainless Steel
•Major types:
– Chromium Martensitic SS
– Chromium Ferritic SS
– Austenitic SS
– Precipitation hardenable SS
– Duplex / Super Duplex SS
•Relatively high coefficient of thermal expansion / low
thermal conductivity
•Protection of molten arc mandatory – prevent chromium
oxide formation
•Pre-weld & Post-weld cleaning crucial – prevent C
contamination / Surface oxidation
•All welding processes other than Oxy-acetylene welding
recommended
•Major types:
– Chromium Martensitic SS
– Chromium Ferritic SS
– Austenitic SS
– Precipitation hardenable SS
– Duplex / Super Duplex SS
•Relatively high coefficient of thermal expansion / low
thermal conductivity
•Protection of molten arc mandatory – prevent chromium
oxide formation
•Pre-weld & Post-weld cleaning crucial – prevent C
contamination / Surface oxidation
•All welding processes other than Oxy-acetylene welding
recommended
Weldability of Martensitic Stainless Steel
•Essentially Fe-Cr-C alloys with 11.5-18% Cr
•Rapid cooling – hardened structure
•E410NiMo, E410 are commonly used consumables
•Weldability improved if welded by Austenitic SS cons.
•Weld joints require PWHT to get optimum property
•Susceptible to Hydrogen cracking
•Preheat & Interpass control required
•Suitable for all Arc welding processes
•Resistance welding (Spot & Flash) possible
•EBW, FSW possible
•Essentially Fe-Cr-C alloys with 11.5-18% Cr
•Rapid cooling – hardened structure
•E410NiMo, E410 are commonly used consumables
•Weldability improved if welded by Austenitic SS cons.
•Weld joints require PWHT to get optimum property
•Susceptible to Hydrogen cracking
•Preheat & Interpass control required
•Suitable for all Arc welding processes
•Resistance welding (Spot & Flash) possible
•EBW, FSW possible
Weldability of Ferritic Stainless Steel
•Fe-Cr-C alloys with>11.5% Cr+ other Ferrite stabilizer
(Mo, Al, Ti, Cb etc) – Low C content
•Non Air-hardenable
•Few Matching filler metal available – however Austenitic
SS / Ni based alloys used as weld metal
•Susceptible to cracking under high restraint / surfacing
•Preheat (~150°C) may be required
•Mostly used in ‘As-welded’ condition – No PWHT
•All types of Arc welding possible
•Resistance welding / Other welding processes available
•Fe-Cr-C alloys with>11.5% Cr+ other Ferrite stabilizer
(Mo, Al, Ti, Cb etc) – Low C content
•Non Air-hardenable
•Few Matching filler metal available – however Austenitic
SS / Ni based alloys used as weld metal
•Susceptible to cracking under high restraint / surfacing
•Preheat (~150°C) may be required
•Mostly used in ‘As-welded’ condition – No PWHT
•All types of Arc welding possible
•Resistance welding / Other welding processes available
Weldability of Austenitic Stainless Steel
•Typical 18%Cr-8%Ni steel
•Cr- Oxidation / Corrosion resistance, Ni & Mn- Stabilize
Austenite
•Better Ductility & Toughness (FCC structure)
•Intentionally little Delta Ferrite (3~8%) added in Weld
metal– to reduce hot cracking sensitivity
•Excessive Delta Ferrite also not allowed – compromise in
corrosion resistance / sigma phase at high temp exposure
•Typical 18%Cr-8%Ni steel
•Cr- Oxidation / Corrosion resistance, Ni & Mn- Stabilize
Austenite
•Better Ductility & Toughness (FCC structure)
•Intentionally little Delta Ferrite (3~8%) added in Weld
metal– to reduce hot cracking sensitivity
•Excessive Delta Ferrite also not allowed – compromise in
corrosion resistance / sigma phase at high temp exposure
Weldability of Austenitic Stainless Steel
Delong Diagram
Delong Diagram
Weldability of Austenitic Stainless Steel
•Improper welding condition (long arc, lack of proper
shielding etc) change Delta Ferrite content
•Sensitization: Slow cooling between 750-375°C – Cr
carbide precipitation at Grain boundaries – Corrosion
attack
•Preheat not required
•Interpass temp control extremely important
•Stress corrosion cracking – Presence of stress + Halogen
atmosphere
•PWHT not required
•Suitable for all types of Arc welding / Plasma welding,
Resistance and other welding processes (EBW, FSW)
•Improper welding condition (long arc, lack of proper
shielding etc) change Delta Ferrite content
•Sensitization: Slow cooling between 750-375°C – Cr
carbide precipitation at Grain boundaries – Corrosion
attack
•Preheat not required
•Interpass temp control extremely important
•Stress corrosion cracking – Presence of stress + Halogen
atmosphere
•PWHT not required
•Suitable for all types of Arc welding / Plasma welding,
Resistance and other welding processes (EBW, FSW)
Weldability of PH Stainless Steel
•Precipitation Hardenable (PH) SS possess high strength
with reasonably simple heat treatment – Martensite
formation / Precipitation hardening
•Three types – Martensitic, Semi-Austenitic & Austenitic
•Martensitic: Martensitic structure + Ageing
•Semi-Austenitic: Initially Austenite after Cooling – Reheat
and cool to convert to Martensite + Ageing
•Austenitic: Austenite + Ageing
•Mostly require PWHT after Welding to restore properties
•All Arc welding / Resistance Welding is possible
•Stringent control on weld parameters / heat input
•Precipitation Hardenable (PH) SS possess high strength
with reasonably simple heat treatment – Martensite
formation / Precipitation hardening
•Three types – Martensitic, Semi-Austenitic & Austenitic
•Martensitic: Martensitic structure + Ageing
•Semi-Austenitic: Initially Austenite after Cooling – Reheat
and cool to convert to Martensite + Ageing
•Austenitic: Austenite + Ageing
•Mostly require PWHT after Welding to restore properties
•All Arc welding / Resistance Welding is possible
•Stringent control on weld parameters / heat input
Weldability of Duplex Stainless Steel
•Typical 40-50% Ferrite + Balance Austenite
•Corrosion (mainly Pitting) resistance + High strength /
toughness
•Low coefficient of Thermal expansion – like CS
•Less prone to hot cracking
•High heat input / interpass: HAZ loses Ductility/
toughness, Phase balance disturbs
•Clean joint, good fit-up very important
•Preheating not required
•PWHT must be avoided (Sigma/ Chi/ Alpha Prime
embrittlement)
•Arc Welding processes / High energy beam welding done
•Typical 40-50% Ferrite + Balance Austenite
•Corrosion (mainly Pitting) resistance + High strength /
toughness
•Low coefficient of Thermal expansion – like CS
•Less prone to hot cracking
•High heat input / interpass: HAZ loses Ductility/
toughness, Phase balance disturbs
•Clean joint, good fit-up very important
•Preheating not required
•PWHT must be avoided (Sigma/ Chi/ Alpha Prime
embrittlement)
•Arc Welding processes / High energy beam welding done
Weldability of Duplex Stainless Steel
Micro Of Standard Duplex
Dark Areas:- Ferrite
Light Areas:- Austenite
Micro Of Standard Duplex
Dark Areas:- Ferrite
Light Areas:- Austenite
Weldability of Ni Alloys
•Ni – FCC structure upto Melting point
•Pure Ni & Solid solution of Ni-Cu, Ni-Cr-Fe, Ni-Cr-Mo
widely used
CHEMICAL
COMPOSITION
Nickel
200
Monel 400
Incoloy
825
Inconel
625
C, Max. 0.08 0.2 0.03 0.05
Mn, 0.2 1.00 0.5 0.2
Si, 0.2 0.20 0.25 0.2
Cu, . 0.1 31.5 2.25 0.2
Ni 99.5 66.5 42 61
Cr, 21.5 21.5
Mo, 3 9
Fe 0.1 1.2 30 2.5
•Ni – FCC structure upto Melting point
•Pure Ni & Solid solution of Ni-Cu, Ni-Cr-Fe, Ni-Cr-Mo
widely used
CHEMICAL
COMPOSITION
Nickel
200
Monel 400
Incoloy
825
Inconel
625
C, Max. 0.08 0.2 0.03 0.05
Mn, 0.2 1.00 0.5 0.2
Si, 0.2 0.20 0.25 0.2
Cu, . 0.1 31.5 2.25 0.2
Ni 99.5 66.5 42 61
Cr, 21.5 21.5
Mo, 3 9
Fe 0.1 1.2 30 2.5
Weldability of Ni Alloys
•Extremely sensitive to surface cleaning / preparation
•Suitable filler metal available for most arc welding process
•Resistance Welding, Oxyacetylene Welding, High Energy
Beam welding possible
•Preheat not required
•Heat input and Interpass temp must be restricted
•Viscous weld metal – prone to solidification / end cracker
cracking – suitable technique required
•PWHT usually not required – however not detrimental
•Extremely sensitive to surface cleaning / preparation
•Suitable filler metal available for most arc welding process
•Resistance Welding, Oxyacetylene Welding, High Energy
Beam welding possible
•Preheat not required
•Heat input and Interpass temp must be restricted
•Viscous weld metal – prone to solidification / end cracker
cracking – suitable technique required
•PWHT usually not required – however not detrimental
Weldability of Al Alloys
•Thermal & electrical conductivity – 4 times of Steel
•Higher heat input required
•Highly prone to oxidation - Refractory oxide formed –
removed / broken during welding
•Most fusion / solid state welding possible
•Suitable filler wires available for arc / oxy-fuel
welding
•Weld prone to cracking – hot shortness, HAZ
inter-granular crack, lesser strength + shrinkage
stress
•Thermal & electrical conductivity – 4 times of Steel
•Higher heat input required
•Highly prone to oxidation - Refractory oxide formed –
removed / broken during welding
•Most fusion / solid state welding possible
•Suitable filler wires available for arc / oxy-fuel
welding
•Weld prone to cracking – hot shortness, HAZ
inter-granular crack, lesser strength + shrinkage
stress
Weldability of Al Alloys
•Prevented by using higher alloyed filler wire
•Surface / Joint cleaning very important
•Preheat – normally not required except high thickness
•AC / DC welding suitable
•Special technique required to prevent crater cracking
•GTAW / GMAW / Solid state welding - most preferred
•Usually PWHT not required
•Prevented by using higher alloyed filler wire
•Surface / Joint cleaning very important
•Preheat – normally not required except high thickness
•AC / DC welding suitable
•Special technique required to prevent crater cracking
•GTAW / GMAW / Solid state welding - most preferred
•Usually PWHT not required
Weldability of Ti Alloys
•Highly reactive – requires protection from atmosphere
•Extremely sensitive to cleaning – special reagents used
•GTAW, GMAW, Plasma & Solid state welding popular
•Gas shielded welding: Use of Trailing gas in addition to
High purity Shielding & Purging gases
•Highly susceptible to porosity
•Colour of weld bead confirms protection from oxidation
•PWHT normally not required
•No Preheat
•Very stringent Interpass temp & Heat input control
•Solid state welding preferred for dissimilar welding
•Highly reactive – requires protection from atmosphere
•Extremely sensitive to cleaning – special reagents used
•GTAW, GMAW, Plasma & Solid state welding popular
•Gas shielded welding: Use of Trailing gas in addition to
High purity Shielding & Purging gases
•Highly susceptible to porosity
•Colour of weld bead confirms protection from oxidation
•PWHT normally not required
•No Preheat
•Very stringent Interpass temp & Heat input control
•Solid state welding preferred for dissimilar welding
Weldability of Ti Alloys
Weld Colour Probable Cause and Treatment
Light Straw, Dark Straw, Light BlueSurface oxide. Remove by wire
brushing with new stainless steel
wire brush.
Dark Blue, Grey Blue, Grey Metal contamination. Welds should
be removed and done over after
corrections in shielding are made.
White (loose deposit) Metal contamination. Welds should
be removed and done over after
corrections in shielding are made
Weld Colour Probable Cause and Treatment
Light Straw, Dark Straw, Light BlueSurface oxide. Remove by wire
brushing with new stainless steel
wire brush.
Dark Blue, Grey Blue, Grey Metal contamination. Welds should
be removed and done over after
corrections in shielding are made.
White (loose deposit) Metal contamination. Welds should
be removed and done over after
corrections in shielding are made
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