铁素体不锈钢焊接热影响区的组织与冲击韧性研究

Microstructure and Impact Toughness of Welding HAZ in Ferritic Stainless Steel

分别采用SMAW和MIG焊方法焊接SUS444铁素体不锈钢,对比了焊接HAZ的金相组织、冲击韧性,并对断口进行了SEM形貌和能谱分析。结果表明,虽然使用小直径焊条和小焊接参数,但SMAW焊接HAZ的晶粒仍发生明显长大,其5 mm厚冲击试样的室温冲击功在10 J以下。MIG焊接采用了高速自动焊接,热输入更小,焊接HAZ晶粒未发生明显长大,其5 mm厚冲击试样的室温冲击功达到40 J以上,0℃冲击功达到10 J以上。

SUS444 ferritic stainless steel was welded by SMAW and MIG welding respecitively. The microstructure and impact toughness of the welded HAZ were compared, and the SEM morphology and energy spectrum analysis of the fracture was carried out. The results show that although small diameter electrode and small welding parameters are used, the grain size of SMAW welding HAZ grows obviously, the room temperature impact energy of 5 mm thick impact samples is lower than 10J. MIG welding adopts high speed automatic welding, and the heat input is smaller, the grain of welding HAZ doesn’t grow significantly, the impact energy of 5 mm thick impact samples reaches more than 40 J at room temperature and more than 10 J at 0℃.