Al-5Zn-1.6Mg合金焊缝中Zn与Mg比值的研究

本文采用钨极氩弧焊并在焊后热处理条件下,通过变动焊丝成分,研究了Al-5Zn-1.6Mg 合金焊缝中Zn Mg 含量和Zn 与Mg 比值对接头性能,特别是对接头应力腐蚀性能的影响规律.指出,接头的抗应力腐蚀性能不仅与焊缝中Zn Mg 含量有关,而且也取决于其中Zn 与Mg 的比值。如果焊缝中Zn Mg 含量一定,则以Zn 与Mg 比值接近2.7时的抗应力腐蚀性能为最好。这些研究结果已经用于海洋构件的试制中.本文还介绍了采用对热裂比较敏感的Al-5Zn-1.6Mg 合金,建造具有多种接头型式的复杂构件时.防止焊接开裂的一些成功经验。

INVESTIGATION OF Zn/Mg RATIO IN THE WELD METAL OF A1-5Zn-1.6Mg ALLOY

The effects of Zn+Mg content and Zn/Mg ratio in the weld metal of Al-5Zn-1.6Mg alloy on the behaviour of joints,and the stress corrosion resistance in particular were investigated by means of varying the filler metal composition with TIG technique and the post-weld heat treatment.Results show that stress corrosion resistance not only relates with the Zn+Mg content,but also depends upon the Zn/Mg ratio in the weld metal.When the Zn/Mg ratio is around 2.7,the greatest resistance to stress corrosion cracking can be obtained provided that the Zn+Mg content is kept constant.Of this conclusion designers of some welded marine structures have taken advantage.Experience in preventing weld cracking in complex structures with various types of joints is also described,the base metal being Al-5Zn-1.6Mg alloy which is susceptible to hot cracking.The strenghth of welded structures in T6 condition was tested.Some of the structures have been immersed in sea-water and others have been exposed to marine atmosphere for four years without any fracture due to stress corrosiom.