Numerical Simulation of Hydrogen Diffusion in X80 Welded Joint Under the Combined Effect of Residual Stress and Microstructure Inhomogeneity
Timing ZHANG1,2, Weimin ZHAO1(), Wei JIANG1, Yonglin WANG1, Min YANG1
1 School of Materials Science and Engineering, China University of Petroleum (East China), Qingdao 266580, China 2 School of Aeronautical Manufacturing Engineering, Nanchang Hangkong University, Nanchang 330063, China
Cite this article:
Timing ZHANG, Weimin ZHAO, Wei JIANG, Yonglin WANG, Min YANG. Numerical Simulation of Hydrogen Diffusion in X80 Welded Joint Under the Combined Effect of Residual Stress and Microstructure Inhomogeneity. Acta Metall Sin, 2019, 55(2): 258-266.
Welded joints of hydrogen-containing coal gas transmission pipelines are prone to hydrogen enrichment due to their severe microstructure inhomogeneity and residual stress in them, and thus lead to the decrease of plasticity and toughness. In order to investigate the effect of local hydrogen enrichment on the safety of hydrogen-containing coal gas transport pipelines, a three dimensional numerical simulation model was established to investigate the hydrogen diffusion behaviour considering the combined effect of microstructure inhomogeneity and residual stress in X80 spiral welded pipeline by using ABAQUS software. Results showed that both microstructure inhomogeneity and residual stress could lead to hydrogen diffusion. The distribution of hydrogen concentration in the pipeline was similar to that of hydrostatic stress distribution. That is, the higher the hydrostatic stress value, the higher the corresponding hydrogen concentration, indicating that the influence of residual stress on the hydrogen diffusion behaviour is greater than that of microstructure inhomogeneity. The enriched hydrogen concentration at the center region of the welded joint with the highest residual stress was 2.7 times higher than that without considering residual stress. Equivalent charging hydrogen pressure was put forward to reflect the degree of hydrogen enrichment in weld metal. Slow strain rate tension (SSRT) tests were subsequently performed on weld metal specimen at equivalent charging hydrogen pressure to investigate the effect of hydrogen enrichment on hydrogen embrittlement (HE) susceptibility. The SSRT tests performed in nitrogen gas and simulated coal gas were used for comparison. The HE index increased from 18.56% in simulated coal gas to 32.53% in equivalent charging hydrogen pressure, increasing by 75.27%. Therefore, the residual stress is a non-ignorable factor, because it could lead to hydrogen enrichment and could significantly influence HE susceptibility in welded joint. The determination of hydrogen enrichment in welded joint by using numerical simulation method is the basis to evaluate the safety of coal gas transmission pipeline.
Fund: Supported by National Natural Science Foundation of China (No.51705535), China Postdoctoral Science Foundation (No.2016M602218) and Natural Science Foundation of Shandong Province (No.ZR2017MEE005)
Table 1 Welding materials and parameters of spiral welded pipe
Fig.1 Morphology and dimension of welded joint (unit: mm)
Fig.2 Hydrogen permeation curves of different sub-regions of welded joint (ICHAZ—intercritical heat affected zone, FGHAZ—fine grained heat affected zone, CGHAZ—coarse grained heat affected zone)
Region
i∞ / (μAcm-2)
D / (10-6 cm2s-1)
C0 / 10-6
S /(10-11 Pa-1/2)
Base metal
0.292
3.302
0.02350
4.797
ICHAZ
0.313
4.138
0.02010
4.103
FGHAZ
0.329
4.990
0.01752
3.576
CGHAZ
0.353
5.477
0.01713
3.497
Weld metal
0.333
5.315
0.01665
3.399
Table 2 Hydrogen diffusion parameters of different sub-regions of welded joint
Fig.3 3D model of pipeline with mesh division (a) overall morphology (b) magnification of welded joint
T / ℃
Rt0.5 / MPa
E / GPa
20
590
210
400
385
187
500
113
142
600
108
138
700
103
120
800
80
118
900
40
97
1000
27
55
Table 3 Mechanical properties of X80 pipeline steel at different temperatures
Fig.4 Cross-sectional macrographs of real (a, c) and simulated (b, d) welded joints (a, b) inner weld (c, d) outer weld
Fig.5 Stress distributions in welded pipeline (a) overall morphology (b) magnification of welded joint with mesh division (c) residual stress distribution curves along line A in Fig.5b
Fig.6 Hydrogen concentration distributions in X80 welded pipeline (a) without residual stress (b) with residual stress (c) hydrogen distribution along line A in Figs. 6a and b
Region
C0 / 10-6
Cmax / 10-6
Base metal
0.02350
0.02752
ICHAZ
0.02010
0.02675
FGHAZ
0.01752
0.02595
CGHAZ
0.01713
0.02659
Weld metal
0.01665
0.02829
Table 4 The hydrogen enrichment at different sub-regions of welded joint
Fig.7 Stress-strain curves of weld metal in different environments
Environment
Rm / MPa
δ / %
Z / %
FH / %
Nitrogen gas
690
16.84
64.21
-
Coal gas
697
14.55
52.12
18.56
Equivalent charging hydrogen
679
14.29
43.18
32.53
Table 5 Mechanical properties of weld metal in different environments
Fig.8 Low (a~c) and high (d~f) magnified fracture SEM images of weld metal in nitrogen gas (a, d), coal gas (b, e) and equivalent charging hydrogen (c, f) environments
[1]
Hao X Q, An H Z, Qi H, et al.Evolution of the exergy flow network embodied in the global fossil energy trade: Based on complex network[J]. Appl. Energy, 2016, 162: 1515
[2]
Dodds P E, McDowall W. The future of the UK gas network[J]. Energy Policy, 2013, 60: 305
[3]
Nie W J, Shang C J, You Y, et al.Microstructure and toughness of the simulated welding heat affected zone in X100 pipeline steel with high deformation resistance[J]. Acta Metall. Sin., 2012, 48: 797(聂文金, 尚成嘉, 由洋等. 抗变形X100管线钢模拟焊接热影响区的组织与韧性研究[J]. 金属学报, 2012, 48: 797)
[4]
Briottet L,Batisse R, de Dinechin G, et al.Recommendations on X80 steel for the design of hydrogen gas transmission pipelines[J]. Int. J. Hydrogen Energy, 2012, 37: 9423
[5]
Dodds P E, Demoullin S.Conversion of the UK gas system to transport hydrogen[J]. Int. J. Hydrogen Energy, 2013, 38: 7189
[6]
Miao C L, Shang C J, Wang X M, et al.Microstructure and toughness of HAZ in X80 pipeline steel with high Nb content[J]. Acta Metall. Sin., 2010, 46: 541(缪成亮, 尚成嘉, 王学敏等. 高Nb X80管线钢焊接热影响区显微组织与韧性[J]. 金属学报, 2010, 46: 541)
[7]
Zhu Z X, Kuzmikova L, Li H J, et al.The effect of chemical composition on microstructure and properties of intercritically reheated coarse-grained heat-affected zone in X70 steels[J]. Metall. Mater. Trans., 2014, 45B: 229
[8]
Chen X W, Qiao G Y, Han X L, et al.Effects of Mo, Cr and Nb on microstructure and mechanical properties of heat affected zone for Nb-bearing X80 pipeline steels[J]. Mater. Des., 2014, 53: 888
[9]
Sowards J W, Gn?upel-Herold T, McColskey J D, et al. Characterization of mechanical properties, fatigue-crack propagation, and residual stresses in a microalloyed pipeline-steel friction-stir weld[J]. Mater. Des., 2015, 88: 632
[10]
Nasim K, Arif A F M, Al-Nassar Y N,D, et al. Investigation of residual stress development in spiral welded pipe[J]. J. Mater. Process. Technol., 2015, 215: 225
[11]
Salerno G, Bennett C, Sun W, et al.On the interaction between welding residual stresses: A numerical and experimental investigation[J]. Int. J. Mech. Sci., 2018, 144: 654
[12]
Jebaraj J J M, Morrison D J, Suni I I. Hydrogen diffusion coefficients through Inconel 718 in different metallurgical conditions[J]. Corros. Sci., 2014, 80: 517
[13]
Rezende M C, Araujo L S, Gabriel S B, et al.Hydrogen embrittlement in nickel-based superalloy 718: Relationship between γ′+γ″ precipitation and the fracture mode[J]. Int. J. Hydrogen Energy, 2015, 40: 17075
[14]
Zhang T M, Wang Y, Zhao W M, et al.Hydrogen permeation parameters of X80 steel and welding HAZ under high pressure coal gas environment[J]. Acta Metall. Sin., 2015, 51: 1101(张体明, 王勇, 赵卫民等. 高压煤制气环境下X80钢及热影响区的氢渗透参数研究[J]. 金属学报, 2015, 51: 1101)
[15]
Zhao W M, Zhang T M, Zhao Y J, et al.Hydrogen permeation and embrittlement susceptibility of X80 welded joint under high-pressure coal gas environment[J]. Corros. Sci., 2016, 111: 84
[16]
Yan C Y, Liu C Y, Yan B.3D modeling of the hydrogen distribution in X80 pipeline steel welded joints[J]. Comput. Mater. Sci., 2014, 83: 158
[17]
Jiang W C, Gong J M, Tang J Q, et al.Finite element simulation of the effect of welding residual stress on hydrogen diffusion[J]. Acta Metall. Sin., 2006, 42: 1221(蒋文春, 巩建鸣, 唐建群等. 焊接残余应力对氢扩散影响的有限元模拟[J]. 金属学报, 2006, 42: 1221)
[18]
Chu W Y, Qiao L J, Li J X, et al.Hydrogen Embrittlement and Stress Corrosion Cracking [M]. Beijing: Science Press, 2013: 37(褚武扬, 乔利杰, 李金许等. 氢脆和应力腐蚀——基础部分 [M]. 北京: 科学出版社, 2013: 37)
[19]
Toribio J, Kharin K, Lorenzo M, et al.Role of drawing-induced residual stresses and strains in the hydrogen embrittlement susceptibility of prestressing steels[J]. Corros. Sci., 2011, 53: 3346
[20]
Zhang X H, Tan C Y, Chen P Y.Numerical simulation of hydrogen diffusion in welded joint[J]. Trans. China Weld. Inst., 2000, 21(3): 51(张显辉, 谭长瑛, 陈佩寅. 焊接接头氢扩散数值模拟(I)[J]. 焊接学报, 2000, 21(3): 51)
[21]
Bell D.Divergence theorems in path space III: Hypoelliptic diffusions and beyond[J]. J. Funct. Anal., 2007, 251: 232
[22]
Chu W Y, Qiao L J, Chen Q Z, et al.Fracture and Environmental Fracture [M]. Beijing: Science Press, 2000: 99(褚武扬, 乔利杰, 陈奇志等. 断裂与环境断裂 [M]. 北京: 科学出版社, 2000: 99)
[23]
Wang Y F, Gong J M, Jiang W C.A quantitative description on fracture toughness of steels in hydrogen gas[J]. Int. J. Hydrogen Energy, 2013, 38: 12503
[24]
Jiang W C, Gong J M, Tang J Q, et al.Numerical simulation of hydrogen diffusion under welding residual stress[J]. Trans. China Weld. Inst., 2006, 27(11): 57(蒋文春, 龚建鸣, 唐建群等. 焊接残余应力下氢扩散的数值模拟[J]. 焊接学报, 2006, 27(11): 57)
[25]
Nanninga N E, Levy Y S, Drexler E S, et al.Comparison of hydrogen embrittlement in three pipeline steels in high pressure gaseous hydrogen environments[J]. Corros. Sci., 2012, 59: 1
[26]
Kong D J, Wu Y Z, Long D.Stress corrosion of X80 pipeline steel welded joints by slow strain test in NACE H2S solutions[J]. J. Iron Steel Res., Int., 2013, 20: 40
