热输入对C300接头温度场及焊缝胞晶组织的影响

通过数值计算和组织观察,分析了热输入对马氏体时效钢(C300)钨极氩弧焊焊接接头温度场及焊缝胞晶组织的影响. 结果表明,试验条件下,随着热输入的增大,熔深和熔宽均增大,深色腐蚀区(HAZ2,heat affected zone 2)逐渐变宽并远离焊缝中心,上窄下宽的差异也将随之增大,760 ℃等温线距热源中心的距离基本符合r=0.465E+0.987 (mm)关系式;胞晶尺寸随着热输入的增大而增大,基本符合λ₂=3.324×E2/3 (μm)关系式,小热输入情况下适用性高. 最佳热输入不仅可以得到成形良好的焊缝,而且计算值与实测值吻合程度较高.

Influence of heat input on welding temperature fields and cellular microstructure of C300 welded joints

In this paper, the influence of heat input on welding temperature field and microstructure of maraging steel C300 TIG (Tungsten Inter Gas Welding, TIG) welded joints were carried out preliminarily. The results indicate that, under these experimental conditions, as the heat input increased, the weld penetration and weld width both increased. The dark band zone (HAZ 2, Heat affected zone 2) widened and was further away from the weld center line, as well as that the difference between the top and bottom of dark band zones was also increased. The distance between 760 ℃ isotherm and the heat source basically satisfies the relationship of r=0.465E+0.987 (mm). The cellular grain size also increased with the increase of the heat input and basically satisfies the relationship λ₂=3.324×E2/3 (μm), and with high applicability in the case of small heat input. Under best welding heat input, not only a good weld shape can be obtained but also a higher degree of agreement between the calculated value and the measured one.