6N01铝合金水冷MIG焊接头组织和性能

Microstructure and mechanical properties of water-cooled MIG welded joints of 6N01 aluminium alloy

关键词:  6N01铝合金  MIG焊  水冷  显微组织  力学性能

Key words:  6N01 aluminum alloy  MIG welding  water cooling  microstructure  mechanical property

摘要:

针对6N01铝合金熔化焊接头软化问题，研究了水冷对MIG焊接头组织和性能的影响，并与自然冷却条件下接头进行对比.金相试验结果表明，水冷使填充和盖面焊道部分熔化区变窄，焊缝近熔合线的柱状晶区变宽，焊缝内部等轴晶细化；显微硬度试验结果表明水冷条件下接头软化区范围明显变窄且硬度提高；软化区TEM观察显示水冷减少了β'析出相长大；水冷还提高了MIG焊接接头屈服强度和抗拉强度.结果表明，水冷能优化6N01铝合金MIG接头组织并提高力学性能.

Abstract:

In order to alleviate the softening problem of 6N01 aluminum alloy during fusion welding, the microstructure and mechanical properties of MIG welded joints with water accelerated cooling were studied and compared with the joints under natural cooling conditions. The results of metallographic experiments showed that the partially melted zones of filling pass and cover pass were narrowed by water cooling. The columnar grain regions of the weld near the fusion line were widened and the equiaxed grains in the weld were refined. Microhardness test results showed that the softening zone of the joint was significantly narrowed and the hardness increased under water cooling conditions. The TEM morphology of the softened zone showed that the sizes of β' precipitation were also reduced. The yield strengths and tensile strengths of MIG welded joints were also improved by water cooling. The experimental results confirmed that water cooling can optimize the microstructure and improve the mechanical properties of MIG welded 6N01 aluminum alloy joints.