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分析了00Cr18Ni10N奥氏体不锈钢点焊接头的显微组织,利用WRC-1992相组分图计算出Creq/Nieq当量比值,通过显微硬度测定值判断了铁素体的析出情况,并估算了点焊的冷却速度。显微组织分析结果表明:在不考虑冷却速度的影响下,通过相组分图的预测,点焊熔核的凝固模式为铁素体加奥氏体模式(FA)。然而,在点焊特殊工艺下,熔核组织由树枝晶和胞状晶组成,可见快速冷却改变了熔核的凝固模式,促使FA模式向AF模式和A转变。硬度测定结果表明:熔核区域的硬度比母材的低。熔核区域的硬度值几乎相同,但由于铁素体在某些区域沿枝晶轴析出,熔核区域的硬度值略有波动。
The microstructure of the spot welded joint of 00Cr18Ni10N austenitic stainless steel was analyzed. The Creq / Nieq equivalence ratio was calculated by WRC-1992 phase diagram, and the precipitation of ferrite was judged by the measured value of microhardness. Welding cooling rate. The results of microstructure analysis show that the solidification mode of spot weld nugget is ferrite plus austenite mode (FA), which is predicted by phase composition without considering the cooling rate. However, in the spot welding special process, the nugget structure consists of dendrites and cellular crystals. It can be seen that the rapid cooling changes the solidification mode of the nugget and the FA mode changes to the AF mode and the A mode. The hardness measurement results show that the hardness of the nugget area is lower than that of the base metal. The hardness values in the nugget area are almost the same, but the hardness value in the nugget area slightly fluctuates due to the precipitation of ferrite along the dendrite axis in some areas.