Impact of Mo/Ni alloying on microstructural modulation and low-temperature toughness of high-strength low-alloy steel  

作　　者：Wei Liu Hong-li Zhao Bing-xing Wang Yong Tian 

机构地区：[1]State Key Laboratory of Rolling and Automation,Northeastern University,Shenyang 110819,Liaoning,China

出　　处：《Journal of Iron and Steel Research International》2024年第7期1746-1762,共17页钢铁研究学报（英文版）

基　　金：supported by the Project of Promoting Talents in Liaoning province (Grant No.XLYC2007036).

摘　　要：The high-strength low-alloy steel plates with varying Ni/Mo contents were manufactured using the thermos-mechanical control process.The investigation was conducted to explore the effect of Ni/Mo microalloying on microstructure evolution and mechanical properties of the steel.The results revealed that the increase in Ni content from 1 to 2 wt.%reduced the transition temperature of ferrite and the growth range of ferritic grain was narrowed,which promoted grain refinement.The optimized combination of grain size,high-angle grain boundaries(HAGBs),and martensite-austenite(M-A)islands parameter contributed to the excellent impact toughness of S1 steel at-100℃(impact absorbed energy of 218.2 J at-100℃).As the Mo increases from 0 to 2 wt.%,the matrix structure changes from multiphase structure to granular bainite,which increases the average effective grain size to~4.62 pm and reduces HAGBs proportion to~36.22%.With these changes,the low-temperature impact toughness of S3 steel is weakened.In addition,based on the analysis of the characteristics of crack propagation path,it was found that M-A islands with low content(~2.21%)and small size(~1.76 pm)significantly retarded crack propagation,and the fracture model of M-A islands with different morphologies was further proposed.Furthermore,correlation between behaviour of delamination and toughness was further analysed by observing delamination size and impact energy parameters.

关 键 词：High-strength low-alloy steel Microstructural regulation Ni addition Mo addition Crack propagation Low-temperature toughness 

分 类 号：TG142.33[一般工业技术—材料科学与工程]