Cause analysis of impact toughness unqualified for S355 series steel
Aiming at the problem of low elongation and unqualified low-temperature impact energy for S355 series steel,S355J2 steel with unqualified impact toughness was sampled for the tensile and the low temperature impact testes and the microstructure and the fracture morphology examinations.The results showed that the centerline segregation and the widmanstatten ferrite organization in the microstructure was the main cause that led to the impact toughness unqualified.Through adjusting TMCP process,increasing the pass reduction and reducing the finish rolling temperature and cooling rate,the toughness of products was greatly improved with the elongation increased by more than 5 ％ and the impact energy by 5 times (up to more than 130 J),which well solved the ductile instability problem of S355 series of steels.
NETL
NSTL
万方数据
维普
