Hydrogen Induced Cracking Susceptibility of High-Strength Line Pipe Steels

Effect of crystallographic orientations on the hydrogen-induced cracking resistance improvement of API 5L X70 pipeline steel under various thermomechanical processing

“…The cleavage {001}//ND texture components including (001)[0 10], (001)<1 30>, (001)<1 20> and (001)<1 10> were developed in sample B, which was rolled at a higher finish rolling temperature (833 • C), could be attributed to recrystallisation of austenite followed by ferrite transformation. The presence of these textures increases the number of possible crack propagations and HIC susceptibility [8]. Also, the formation of {112}//ND components, that dominate the (112)[0 21] and (112) [ 1 11] orientations, was observed in this condition.…”

“…Stress corrosion cracking (SCC) and hydrogen-induced cracking (HIC), are considered as the main damage modes in the sour environment [4][5][6] and cause a considerable amount of economic loss to the petroleum industry. Therefore, many strategies have been proposed to reduce HIC susceptibility including adding micro-alloying elements such as titanium, niobium and vanadium, decreasing sulphur and phosphorus contents, controlling the morphology of manganese sulphides, removing precipitation and segregation zones during solution heat treatment and reducing the number of hydrogen trapping [7][8][9]. However, these strategies have not effectively succeeded to control HIC susceptibility.…”

Hydrogen Diffusivity in the Welding Zone of Two High Strength Experimental Microalloyed Steels

“…In the CGHAZ microhardness is higher than that of the BM due to the formation of martensite, and in the FZ microhardness decreased due to the formation of bainite. Increasing the hardness of the welding zone, is related to the increase in yield stress and the generation of residual stresses by thermal gradients and phase transformations (high chemical activity zone), and these in turn are related to increased susceptibility to HIC, 6,15,29,30) so it would expect that the CGHAZ to be the subzone more susceptible of both steels, particularly the subzone of the M1 steel. During the preparation of the solution for silver decoration, the most likely reactions that present are: 25) AgNO KCN AgCN KNO Fig.…”

Study of texture and microstructure evaluation of steel API 5L X70 under various thermomechanical cycles

“…This segregation zone has a higher hardness than other regions. Matsumoto et al [6] studied the crack initiation susceptibility on high strength pipeline steel and showed that the hardness of the segregation zone in steel plate is a determinant factor in increasing the crack formation. Szpunar et al [7] investigated on hydrogen embrittlement (HE) in pipeline steel and found out that the effect of center segregation zone on HE susceptibility can be removed by applying thermo-mechanical control processing (TMCP).…”