中文摘要：

通过金相分析、室温拉伸以及维氏硬度测试等对4003铁素体不锈钢的等离子＋TIG复合焊焊缝晶粒尺寸及力学性能等进行了研究。试验结果表明：4003铁素体不锈钢的等离子＋TIG复合焊接能够得到成形良好的焊缝。热输入在1.12～1.26 k J/mm时,热输入越低焊缝晶粒尺寸越小,最小的平均晶粒尺寸为28.7μm。等离子气流量为4.0 L/min时可以获得相对细小的晶粒。适当加快焊缝焊后冷却速度也能够起到细化晶粒尺寸的作用。不同的工艺参数下焊接接头拉伸试样均断裂在母材处,表明等离子＋TIG复合焊能得到较高性能的焊缝。焊接接头焊缝区的硬度最高,热影响区次之,母材最低。

英文摘要：

The grain size and mechanical properties of plasma and TIG hybrid weld for 4003 ferritic stainless steel were studied by metallographic analysis, tensile test at room temperature and Vickers hardness test. The results show that good weld appearance of 4003 ferritic stainless steel can be obtained by using plasma and TIG hybrid welding. In the heat input 1.12-1.26 kJ/mm, the lower the heat input is, the smaller the weld grain size is, and the smallest average gram size is 28.7 μm. When the plasma gas flow rate is 4.0 L/min, relatively fine grains can be obtained. The increase of cooling rate after welding can also play a role in refining the grain size. The tensile specimens of welded joints were broken at base metal under different process parameters, which shows that the plasma and TIG hybrid welding can get welds with high performance. The microhardness of weld zone is the highest, followed by that of beat-affected zone, and the microhardness of base metal is the minimum.