Evaluation of hydrogen induced cracking behavior of API X70 pipeline steel at different heat treatments

2014 ◽  
Vol 39 (11) ◽  
pp. 6076-6088 ◽  
Author(s):  
M.A. Mohtadi-Bonab ◽  
J.A. Szpunar ◽  
L. Collins ◽  
R. Stankievech
Keyword(s):  
Pipeline Steel ◽  
Heat Treatments ◽  
Cracking Behavior ◽  
X70 Pipeline Steel ◽  
Hydrogen Induced Cracking

scholarly journals Research on hydrogen-induced cracking behavior of normalized pipeline steel

2018 ◽  
Vol 175 ◽  
pp. 01027
Author(s):  
Hai Zhang ◽  
Shaopo Li ◽  
Wenhua Ding ◽  
Ning Hao
Keyword(s):  
Hydrogen Sulfide ◽  
Corrosion Test ◽  
Pipeline Steel ◽  
Plate Thickness ◽  
Hardness Test ◽  
Propagation Path ◽  
Cracking Behavior ◽  
Hydrogen Induced Cracking ◽  
Sulfide Corrosion ◽  
Hydrogen Sulfide Corrosion

Hydrogen sulfide corrosion test was used to test the hydrogen-induced cracking sensitivity of the normalized BNS pipeline steel. The microstructure and morphology of hydrogen induced crack(HIC) of the normalized BNS pipeline steel after hydrogen sulfide corrosion test were observed with optical microscopy(OM), scanning electron microscopy(SEM). Combined with electron probe microanalyzer(EPMA) and hardness test, the hydrogen-induced cracking behavior of BNS pipeline steel was studied from the aspects of microstructure, crack morphology, center segregation and harness. The results showed that the pearlite band with high hardness caused by center segregation of C and Mn was the main crack initiation and propagation path for the long-size and linear shape hydrogen induced crack at the center of plate thickness, and the type of crack propagation was transgranular. Some tiny hydrogen induced crack nucleated from the small calcium-aluminate inclusion and the tiny hydrogen induced crack would not propagate to form long-size cracks with no suitable propagation path existing around the inclusion.

X-Ray Analysis of Residual Stress in Weld Region of X70 Pipeline Steel

2014 ◽  
Vol 936 ◽  
pp. 2011-2016 ◽  
Author(s):  
Zakaria Boumerzoug ◽  
Kelthoum Digheche ◽  
Vincent Ji
Keyword(s):  
Residual Stress ◽  
Stress Distribution ◽  
Pipeline Steel ◽  
Welding Process ◽  
Diffraction Method ◽  
Optical Microscope ◽  
Heat Treatments ◽  
X70 Pipeline Steel ◽  
X Ray ◽  
Weld Region

X-ray diffraction method has been used to analyze the residual stress distribution in weld region of an X70 pipeline steel before and after heat treatment. The welding process has been realized by industrial arc welding with circular weld seams. The effect of heat treatments on the level and the distribution of residual stresses were investigated. Stress distribution was characterized by relative high compressive stresses in weld seam just after welding. However, residual stress relaxation phenomenon was observed in weld region after heat treatments due to microstructure restoration and recrystalization. Optical microscope observation and Vickers hardness measurements were also realized as complementary microstructure characterization techniques.

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