The joining of Mg alloy to steel was realized by metal inert-gas arc welding, and the weld thermal cycle characteristics and Mg-steel joints were investigated. The results show that the temperature distribution in the...The joining of Mg alloy to steel was realized by metal inert-gas arc welding, and the weld thermal cycle characteristics and Mg-steel joints were investigated. The results show that the temperature distribution in the joints is uneven. Mg alloy welds present a fine equiaxed grain structure. There exists a transition layer consisting mainly of AlFe, AlFe3 and Mg（Fe, Al）2O4 phases at Mg/steel interface, and it is the weakest link in Mg？steel joints. The welding heat input and weld Al content have the significant effect on the joint strength. The joint strength increases with increasing the heat input from 1680 J/cm to 2093 J/cm, due to promoting Mg/steel interface reaction. When weld Al content is increased to 6.20%, the joint strength reaches 192 MPa, 80% of Mg alloy base metal strength. It is favorable to select the suitable welding heat input and weld Al content for improving joint strength.展开更多
Micro plasma arc surface melting of 0Cr19Ni9 shielded metal arc welding joint with a micro plasma arc welder produced a thin surface melted layer with a refined microstructure. The surface treatment changed the anod...Micro plasma arc surface melting of 0Cr19Ni9 shielded metal arc welding joint with a micro plasma arc welder produced a thin surface melted layer with a refined microstructure. The surface treatment changed the anodic polarization behavior in 0.5 mol/L H 2SO 4 solution. The polarization tests showed that for the as welded joint both the heat affected zone and the weld metal decreased in resistance to corrosion compared with the as received parent material while for the micro plasma arc surface melted joint the corrosion resistance increased significantly. This increase in corrosion resistance is attributed to the rapid solidification of the melted layer. Rapid solidification of the melted layer refines its microstructure, decreases its microsegregation, and inhibits the precipitation of chromium carbides at the grain boundaries.展开更多
人们普遍认为，由于药芯焊丝熔化极气体保护焊（FCAW）和熔化极气体保护焊（GMAW）等“新”的焊接效率和自动化程度更高的焊接工艺的应用，气体保护金属极电弧焊（SMAW）用涂药焊条正在失去昔日的光辉。尽管如此，Bohler Welding Group ...人们普遍认为，由于药芯焊丝熔化极气体保护焊（FCAW）和熔化极气体保护焊（GMAW）等“新”的焊接效率和自动化程度更高的焊接工艺的应用，气体保护金属极电弧焊（SMAW）用涂药焊条正在失去昔日的光辉。尽管如此，Bohler Welding Group Nordic已决定在其下属的Avesta Welding焊条生产厂投资生产不锈钢涂药焊条。公司技术副经理兼本项目负责人Martin Larén先生说，“四百万瑞典克朗的投资将用于更新改造涂药焊条的生产设备。改造完成后，涂药焊条的产能将增加50％，同时，设备的生产效率更高。作为集团公司正在开展的精益生产项目的一部分，我们还正在重建和改造生产厂的布局。”展开更多
文摘The joining of Mg alloy to steel was realized by metal inert-gas arc welding, and the weld thermal cycle characteristics and Mg-steel joints were investigated. The results show that the temperature distribution in the joints is uneven. Mg alloy welds present a fine equiaxed grain structure. There exists a transition layer consisting mainly of AlFe, AlFe3 and Mg（Fe, Al）2O4 phases at Mg/steel interface, and it is the weakest link in Mg？steel joints. The welding heat input and weld Al content have the significant effect on the joint strength. The joint strength increases with increasing the heat input from 1680 J/cm to 2093 J/cm, due to promoting Mg/steel interface reaction. When weld Al content is increased to 6.20%, the joint strength reaches 192 MPa, 80% of Mg alloy base metal strength. It is favorable to select the suitable welding heat input and weld Al content for improving joint strength.
文摘Micro plasma arc surface melting of 0Cr19Ni9 shielded metal arc welding joint with a micro plasma arc welder produced a thin surface melted layer with a refined microstructure. The surface treatment changed the anodic polarization behavior in 0.5 mol/L H 2SO 4 solution. The polarization tests showed that for the as welded joint both the heat affected zone and the weld metal decreased in resistance to corrosion compared with the as received parent material while for the micro plasma arc surface melted joint the corrosion resistance increased significantly. This increase in corrosion resistance is attributed to the rapid solidification of the melted layer. Rapid solidification of the melted layer refines its microstructure, decreases its microsegregation, and inhibits the precipitation of chromium carbides at the grain boundaries.
