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利用Gleeble-3800模拟焊接粗晶热影响区(CGHAZ)经历的热循环过程。比较了热输入100 k J/cm条件下,V钢、V-N钢、V-Ti钢和V-N-Ti钢CGHAZ的组织和韧性,并分析了析出相情况。结果表明,CGHAZ的韧性从高到低依次为V-N-Ti钢、V-Ti钢、V-N钢和V钢;在V钢成分基础上添加钛可以有效细化原始奥氏体晶粒尺寸;V-Ti钢成分基础上增氮,一方面促进了(Ti,V)(C,N)/Ti N的析出,抑制了原始奥氏体晶粒的粗化;另一方面促进了V(C,N)的析出,其促进了多边形铁素体的形成;多边形铁素体数量的增加能够减弱自由氮对韧性的破坏,同时有效改善了CGHAZ韧性。
Gleeble-3800 was used to simulate the thermal cycling experienced by CGHAZ. The microstructure and toughness of VHA steel, V-N steel, V-Ti steel and V-N-Ti steel CGHAZ were compared under heat input of 100 kJ / cm and the precipitated phase was analyzed. The results show that the toughness of CGHAZ is VN-Ti steel, V-Ti steel, VN steel and V steel from high to low; the addition of titanium to V steel can effectively refine the original austenite grain size; V- The increase of nitrogen on the basis of the composition of Ti steel promoted the precipitation of (Ti, V) (C, N) / TiN and inhibited the coarsening of the original austenite grains on the one hand, and promoted the formation of V (C, N ), Which promotes the formation of polygonal ferrite. The increase of polygonal ferrite can weaken the damage of free nitrogen to the toughness and effectively improve the toughness of CGHAZ.