The influence of phosphorus on the temper embrittlement and hydrogen embrittlement of some dual-phase steels
Futao Dong, Jeffrey Venezuela, Huixing Li, Zhiming Shi, Qingjun Zhou, Liansheng Chen, Jun Chen, Linxiu Du, Andrej Atrens
Abstract
The temper embrittlement (TE) and hydrogen embrittlement (HE) of some dual-phase (DP) steels were investigated, focusing on the influence of the phosphorus (P) content. An increased P content of 0.02 wt% caused little TE and enhancement of HE susceptibility in DP steels. Hydrogen had little influence on strength , but caused a significant decrease in ductility. For the DP steels with the different microstructures, the hydrogen-induced cracks initiated at the specimen surface, and hydrogen-induced micro-crack initiation was mainly martensite related. The increased martensite related cracking and the tendency of interface cracking was attributed by the enhanced element segregation (by both increased tendency of P segregation and promoted by other element segregation like Mn). The increased P content can enhance HE susceptibility through both interface weakening related HE mechanisms (HESIV, HEDE, or defactant) and ferrite ductility loss related HELP mechanism.