This study designed post-weld heat treatments, including reheating and tempering, associated with hot bending to investigate the microstructures, toughness, and hardness of two weld metals with different Ni contents (<1 wt pct level). The results indicated that a high Ni content decreased the ferrite transformation temperature and increased the proportion of acicular ferrite (AF). Furthermore, a high Ni content promoted the martensite/austenite (M/A) constituent formation after reheating. The promotion of the M/A formation increased the number of cementite particles, and accelerated cementite coarsening during tempering. The large-angle grain boundary density from the AF improved the toughness despite the negative effect of cementite. The strengthening contributions were calculated, and the grain refinement was the greatest. The high Ni content decreased the effective grain size with a 2 deg tolerance angle, thus enhancing the grain refinement contribution.

这项研究设计了与热弯曲相关的焊后热处理，包括再加热和回火，以研究两种镍含量不同（<1 wt pct水平）的焊接金属的显微组织，韧性和硬度。结果表明，较高的Ni含量会降低铁素体的转变温度，并增加针状铁素体（AF）的比例。此外，高Ni含量促进了再加热后马氏体/奥氏体（M / A）成分的形成。M / A形成的促进增加了渗碳体颗粒的数量，并加速了回火过程中渗碳体的粗化。尽管渗碳体有负面影响，但AF产生的大角度晶界密度提高了韧性。计算出强化贡献，晶粒细化最大。