Creep strength ferritic/martensitic modified 9Cr-1Mo-V-Nb (P91) steel also designated as ASTM A335 and P92 steel are used for piping, cladding, ducts, wrappers, and the pressure vessel in Gen IV nuclear reactors. In the present investigation, a comparative study of the effect of autogenous tungsten inert gas welding (A-TIG) with double pass and multipass gas tungsten arc (GTA) welding with filler on microstructure evolution in the weld fusion zone and the mechanical properties of P91 and P92 steel welded joints was carried out. The microstructure evolution was studied in as-welded and postweld heat treatment (PWHT) condition. The study also focused on the evolution of δ-ferrite patches and their influence on the tensile properties of welded joints. PWHT was carried out at 760 °C with durations from 2 to 6 h. To study the effect of δ-ferrite evolution on mechanical properties, Charpy toughness, microhardness, and tensile tests were performed. The acceptable microstructure and mechanical properties were obtained after the 6 h of PWHT for A-TIG arc welding process while for GTA weld with filler wire, it was obtained after the 2 h of PWHT at 760 °C.

References

References
1.
Swindeman
,
R. W.
,
Santella
,
M. L.
,
Maziasz
,
P. J.
,
Roberts
,
B. W.
, and
Coleman
,
K.
,
2004
, “
Issues in Replacing Cr–Mo Steels and Stainless Steels With 9Cr–1Mo–V Steel
,”
Int. J. Pressure Vessels Piping
,
81
(
6
), pp.
507
512
.
2.
Pandey
,
C.
, and
Mahapatra
,
M. M.
,
2016
, “
Effect of Heat Treatment on Microstructure and Hot Impact Toughness of Various Zones of P91 Welded Pipes
,”
J. Mater. Eng. Perform.
,
25
(
6
), pp.
2195
2210
.
3.
Sireesha
,
M.
,
Albert
,
S. K.
, and
Sundaresan
,
S.
,
2001
, “
Microstructure and Mechanical Properties of Weld Fusion Zones in Modified 9Cr-1Mo Steel
,”
J. Mater. Eng. Perform.
,
10
(
3
), pp.
320
330
.
4.
Arivazhagan
,
B.
, and
Vasudevan
,
M.
,
2014
, “
A Comparative Study on the Effect of GTAW Processes on the Microstructure and Mechanical Properties of P91 Steel Weld Joints
,”
J. Manuf. Processes
,
16
(
2
), pp.
305
311
.
5.
Pandey
,
C.
,
Narang
,
H. K.
,
Saini
,
N.
,
Mahapatra
,
M. M.
, and
Kumar
,
P.
,
2017
, “
Microstructure and Transverse Shrinkage Stress Analysis in GTA Welds of P91 Steel Pipe
,”
Int. J. Steel Struct.
,
17
(
2
), pp.
763
774
.
6.
Pandey
,
C.
,
Saini
,
N.
,
Mahapatra
,
M. M.
, and
Kumar
,
P.
,
2016
, “
Hydrogen Induced Cold Cracking of Creep Resistant Ferritic P91 Steel for Different Diffusible Hydrogen Levels in Deposited Metal
,”
Int. J. Hydrogen Energy
,
41
(
39
), pp.
17695
17712
.
7.
Pandey
,
C.
,
Mohan
,
M.
,
Kumar
,
P.
, and
Saini
,
N.
,
2018
, “
Dissimilar Joining of CSEF Steels Using Autogenous Tungsten-Inert Gas Welding and Gas Tungsten Arc Welding and Their Effect on δ-Ferrite Evolution and Mechanical Properties
,”
J. Manuf. Processes
,
31
, pp.
247
259
.
8.
Arivazhagan
,
B.
,
Srinivasan
,
G.
,
Albert
,
S. K.
, and
Bhaduri
,
A. K.
,
2011
, “
A Study on Influence of Heat Input Variation on Microstructure of Reduced Activation Ferritic Martensitic Steel Weld Metal Produced by GTAW Process
,”
Fusion Eng. Des.
,
86
(
2–3
), pp.
192
197
.
9.
Arivazhagan
,
B.
,
Sundaresan
,
S.
, and
Kamaraj
,
M.
,
2009
, “
A Study on Influence of Shielding Gas Composition on Toughness of Flux-Cored Arc Weld of Modified 9Cr-1Mo (P91) Steel
,”
J. Mater. Process. Technol.
,
209
(
12–13
), pp.
5245
5253
.
10.
Pandey
,
C.
,
Mahapatra
,
M. M.
,
Kumar
,
P.
, and
Saini
,
N.
,
2017
, “
Effect of Normalization and Tempering on Microstructure and Mechanical Properties of V-Groove and Narrow-Groove P91 Pipe Weldments
,”
Mater. Sci. Eng. A
,
685
, pp.
39
49
.
11.
Pandey
,
C.
, and
Mahapatra
,
M. M.
,
2016
, “
Effect of Groove Design and Post-Weld Heat Treatment on Microstructure and Mechanical Properties of P91 Steel Weld
,”
J. Mater. Eng. Perform.
,
25
(
7
), pp.
2761
2775
.
12.
Pandey
,
C.
,
Mahapatra
,
M. M.
,
Kumar
,
P.
, and
Giri
,
A.
,
2017
, “
Microstructure Characterization and Charpy Toughness of P91 Weldment for As-Welded, Post-Weld Heat Treatment and Normalizing & Tempering Heat Treatment
,”
Met. Mater. Int.
,
23
(
5
), pp.
900
914
.
13.
Pandey
,
C.
,
Mahapatra
,
M. M.
,
Kumar
,
P.
,
Saini
,
N.
, and
Srivastava
,
A.
,
2017
, “
Microstructure and Mechanical Property Relationship for Different Heat Treatment and Hydrogen Level in Multi-Pass Welded P91 Steel Joint
,”
J. Manuf. Processes
,
28
(Pt. 1), pp.
220
234
.
14.
Pandey
,
C.
,
Mahapatra
,
M. M.
,
Kumar
,
P.
, and
Saini
,
N.
,
2017
, “
Diffusible Hydrogen Level in Deposited Metal and Their Effect on Tensile Properties and Flexural Strength of P91 Steel
,”
ASME J. Eng. Mater. Technol.
,
139
(
3
), p.
031004
.
15.
Pandey
,
C.
,
Mahapatra
,
M. M.
,
Kumar
,
P.
, and
Saini
,
N.
,
2018
, “
Comparative Study of Autogenous Tungsten Inert Gas Welding and Tungsten Arc Welding With Filler Wire for Dissimilar P91 and P92 Steel Weld Joint
,”
Mater. Sci. Eng. A
,
712
, pp.
720
737
.
16.
Wang
,
Y.
,
Kannan
,
R.
,
Zhang
,
L.
, and
Li
,
L.
,
2017
, “
Microstructural Analysis of the As-Welded Heat-Affected Zone of a Grade 91 Steel Heavy Section Weldment
,”
Weld. J.
,
96
(6), pp.
203
219
.
17.
Pandey
,
C.
,
Mahapatra
,
M. M.
,
Kumar
,
P.
,
Saini
,
N.
,
Thakre
,
J. G.
,
Vidyarthy
,
R. S.
, and
Narang
,
H. K.
,
2018
, “
A Brief Study on δ-Ferrite Evolution in Dissimilar P91 and P92 Steel Joint and Their Effect on Mechanical Properties
,”
Arch. Civ. Mech. Eng.
,
18
(
3
), pp.
713
722
.
18.
Saini
,
N.
,
Pandey
,
C.
,
Mohan
,
M.
, and
Mulik
,
R. S.
,
2018
, “
Evolution of Nano-Size Precipitates During Tempering of 9Cr-1Mo-1W-V-Nb Steel and Their Influence on Mechanical Properties
,”
Mater. Sci. Eng. A
,
711
, pp.
37
43
.
19.
Yan
,
W.
,
Wang
,
W.
,
Shan
,
Y. Y.
, and
Yang
,
K.
,
2013
, “
Microstructural Stability of 9-12%Cr Ferrite/Martensite Heat-Resistant Steels
,”
Front. Mater. Sci.
,
7
(
1
), pp.
1
27
.
20.
Pandey
,
C.
,
Mahapatra
,
M. M.
,
Kumar
,
P.
,
Vidyrathy
,
R. S.
, and
Srivastava
,
A.
,
2017
, “
Microstructure-Based Assessment of Creep Rupture Behaviour of Cast-Forged
,”
Mater. Sci. Eng. A
,
695
, pp.
291
301
.
21.
Pandey
,
C.
,
Mahapatra
,
M. M.
,
Kumar
,
P.
,
Saini
,
N.
, and
Thakre
,
J. G.
,
2017
, “
Nano-Size Particle Evolution During Heat Treatment of P91 Steel and Their Effect on Micro Hardness
,”
Trans. Indian Inst. Met.
, epub.
22.
Pandey
,
C.
,
Mahapatra
,
M. M.
,
Kumar
,
P.
, and
Saini
,
N.
,
2018
, “
Effect of Strain Rate and Notch Geometry on Tensile Properties and Fracture Mechanism of Creep Strength Enhanced Ferritic P91 Steel
,”
J. Nucl. Mater.
,
498
, pp.
176
186
.
23.
Pandey
,
C.
,
Saini
,
N.
,
Mahapatra
,
M. M.
, and
Kumar
,
P.
,
2017
, “
Study of the Fracture Surface Morphology of Impact and Tensile Tested Cast and Forged (C&F) Grade 91 Steel at Room Temperature for Different Heat Treatment Regimes
,”
Eng. Failure Anal.
,
71
, pp.
131
147
.
24.
Panait
,
C. G.
,
Zielinska-Lipiec
,
A.
,
Koziel
,
T.
,
Czyrska-Filemonowicz
,
A.
,
Gourgues-Lorenzon
,
A. F.
, and
Bendick
,
W.
,
2010
, “
Evolution of Dislocation Density, Size of Subgrains and MX-Type Precipitates in a P91 Steel During Creep and During Thermal Ageing at 600 °C for More Than 100,000 h
,”
Mater. Sci. Eng. A
,
527
(
16–17
), pp.
4062
4069
.
25.
Pandey
,
C.
,
Mahapatra
,
M. M.
,
Kumar
,
P.
, and
Saini
,
N.
,
2017
, “
Homogenization of P91 Weldments Using Varying Normalizing and Tempering Treatment
,”
Mater. Sci. Eng. A
,
710
, pp. 86–101.
26.
Pandey
,
C.
,
Giri
,
A.
, and
Mahapatra
,
M. M.
,
2016
, “
Effect of Normalizing Temperature on Microstructural Stability and Mechanical Properties of Creep Strength Enhanced Ferritic P91 Steel
,”
Mater. Sci. Eng. A
,
657
, pp.
173
184
.
27.
Shyu
,
S. W.
,
Huang
,
H. Y.
,
Tseng
,
K. H.
, and
Chou
,
C. P.
,
2008
, “
Study of the Performance of Stainless Steel A-TIG Welds
,”
J. Mater. Eng. Perform.
,
17
(
2
), pp.
193
201
.
28.
Oñoro
,
J.
,
2006
, “
Martensite Microstructure of 9–12% Cr Steels Weld Metals
,”
J. Mater. Process. Technol.
,
180
(1–3), pp.
137
142
.
29.
Anderko
,
K.
,
Sch
,
L.
, and
Ewaiom
,
A. K.
,
1991
, “
Effect of the δ-Ferrite Phase on the Impact Properties Chromium Steels
,”
J. Nucl. Mater.
,
179–181
(Pt. 1), pp.
492
495
.
30.
Onizawa
,
T.
,
Wakai
,
T.
,
Ando
,
M.
, and
Aoto
,
K.
,
2008
, “
Effect of V and Nb on Precipitation Behavior and Mechanical Properties of High Cr Steel
,”
Nucl. Eng. Des.
,
238
(
2
), pp.
408
416
.
31.
Schafer
,
L.
,
1998
, “
Influence of Delta Ferrite and Dendritic Carbides on the Impact and Tensile Properties of a Martensitic Chromium Steel
,”
J. Nucl. Mater.
,
258–263
(Pt. 2), pp.
1336
1339
.
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