船用高强钢激光-GMAW复合焊及落锤冲击性能研究

Laser⁃GMAW hybrid welding process and drop hammer impact property of marine high⁃strength steel

针对8 mmQ355B船用高强钢,用0.84、1.00 MJ/m两种热输入对其进行激光-GMAW复合焊试验,研究两种热输入下的焊接接头组织和落锤冲击性能。结果表明:在0.84、1.00 MJ/m两种热输入下的焊缝成形良好,无裂纹、塌陷等缺陷;焊接接头组织均为针状铁素体和板条贝氏体,热影响区主要由板条马氏体和板条贝氏体组成,随热输入的增大,焊接接头热影响区明显增宽;两种热输入下的焊接接头均有良好的落锤冲击性能,接头断裂在母材处,断口为准解理断裂,焊接接头的冲击性能均高于母材。

Two heat inputs of 0.84 MJ/m and 1 MJ/m were used to weld 8 mm Q355B marine high⁃strength steel by laser⁃GMAW hybrid welding test,and the microstructure and drop hammer impact properties of welded joint under different heat inputs were studied.The results show that the weld shaping is fine without crack and collapse under the heat inputs of 0.84 MJ/m and 1 MJ/m.The structures of welded joints are acicular ferrite and lath bainite,and the heat affected zones are mainly composed of lath martensite and lath bainite.With the increase of heat input,the heat affected zone of welded joints widens obviously.The welded joints under two heat inputs have good drop hammer impact performance.The joints break at the base material and the fracture is quasi⁃cleavage fracture.The impact properties of welded joints are higher than those of base materials.