论文部分内容阅读
采用不同热输入对12mm SS400超细晶钢进行焊接,并对焊接接头过热区、正火区及不完全正火区晶粒长大程度与组织变化情况进行分析.结合有限元数值模拟的方法研究焊接热影响区及各子区宽度、组织、硬度随热输入的变化规律,得出焊接热输入与HAZ宽度关系曲线符合Boltzmann平衡态理论.试验结果表明,热输入为9.6~22kJ/cm进行焊接时,HAZ及各子区宽度变化较小;当热输入大于22kJ/cm时,HAZ宽度随热输入的增加而增加,尤其正火区宽度大幅增长.同时,过热区组织随着热输入增加片状贝氏体减少,逐步形成粗大的魏氏组织.接头硬度峰值逐渐升高,局部软化区逐渐扩大.在大热输入焊接时,焊接预热可有效抑制热影响区宽度发展.
Different heat input was used to weld 12mm SS400 ultrafine-grained steel and the degree of grain growth and microstructure change in overheated zone, normalized zone and incomplete normalized zone were analyzed.Combined with the method of finite element numerical simulation The results show that the relationship between the welding heat input and HAZ width is in accordance with the Boltzmann equilibrium theory.The experimental results show that the heat input is 9.6 ~ 22kJ / cm for welding When the heat input is greater than 22kJ / cm, the width of HAZ increases with the increase of heat input, especially the width of normalized zone increases sharply.While the overheated zone increases with the increase of heat input Like bainite is reduced, and the coarse Widman’s tissue is gradually formed. The peak hardness of the joint gradually increases, and the local softening zone gradually expands. During the welding with large heat input, the welding preheating can effectively suppress the width development of the heat-affected zone.