焊接方法对430不锈钢焊接接头组织性能的影响

Effect of Welding Method on Microstructure and Mechanical Properties of 430 Stainless Steel Welded Joints

通过金相观察、拉伸试验和显微硬度测试等技术,研究了采用熔化极气体保护焊(MAG)和激光-熔化极气体保护复合焊(LW-MAG)两种工艺焊接的430铁素体不锈钢接头组织与力学性能的差异。结果表明,LW-MAG焊接接头具有更大的深宽比,余高及热影响区宽度也明显小于MAG焊接接头的;LW-MAG和MAG焊接接头高温热影响区组织均为铁素体和晶界马氏体,但MAG焊接接头铁素体晶粒长大明显,晶界马氏体体积较大;MAG焊接接头低温热影响区组织为铁素体、马氏体和未溶解的碳化物,而LW-MAG焊接接头低温热影响区组织为铁素体和碳化物;由于MAG焊接接头热影响区晶界马氏体体积较大,硬度值要高于LW-MAG焊接接头的。

The differences of microstructure and mechanical properties of 430 ferrite stainless steel joints welded by gas metal arc welding(MAG) and laser welding-gas metal arc welding(LW-MAG) were studied by means of metallographic observation, tensile test and microhardness test. The results show that the LW-MAG welded joint has bigger depth-width ratio, the remaining height and the width of the heat affected zone are obviously smaller than those of the MAG welded joint. The microstructure of the high temperature heat affected zone of LW-MAG and MAG welded joints is ferrite and grain boundary martensite, while the ferrite grain of MAG welded joint is obviously bigger and the volume of grain boundary martensite is bigger;the microstructure of the low temperature heat affected zone of the MAG welded joint is ferrite, martensite and undissolved carbides, while the microstructure of the LW-MAG welded joint is ferrite and carbides.The hardness of the MAG welded joint is higher than that of the LW-MAG welded joint because of large volume of martensite at grain boundary in the heat affected zone of the MAG welded joint.