铌对高强钢焊接热影响区中马氏体-奥氏体组元形态的影响

Effect of Niobium on Mophology of Martensite-austenite Constituents in Weld HAZ

对铌（Ｎｂ）含量不同的五种钢材进行焊接热循环模拟焊接热影响区粗晶区（ＣＧＨＡＺ），研究Ｎｂ含量对粗晶区中ＭＡ组元的形态和粗晶区韧性的影响。结果表明，降低钢材的Ｎｂ含量能够减少细长ＭＡ组元的含有率，从而控制ＣＧＨＡＺ的韧性。因此进行实际钢材化学成分设计时，在满足强度要求的条件下，应尽量降低Ｎｂ的含量。

Influence of niobium content on the morphology of the martensite-austenite(MA) constituents in the coarse grained heat affected zone (CGHAZ) of weld and the toughness of CGHAZ was studied by simulating CGHAZ of five kinds of high strength steels with different niobium content. The results show that the volume fraction of the slender M-A constituents reduced with the decrease in niobuim content,thus the toughness of CGHAZ could be controled.As a result,niobium content should be reduced during the chemical composition design for high strength steel if the strength was satisfied.