异种钛合金TIG焊接接头的组织和性能

Structure and Properties on Welding Joints of Dissimilar Titanium Alloy TIG

本文针对800MPa级的Ti6Al4V和600MPa级的∏T3B钛合金板材,选取与∏T3B匹配的2B焊丝,并采用手工钨极氩弧焊的方法进行焊接。焊后对接头的力学性能进行了测试,同时对接头的不同部位进行了显微组织观察和硬度试验试验结果表明:拉伸试样断裂在∏T3B母材,即采用低强度等级的焊丝焊接,由于Ti6Al4V合金元素向焊缝的过渡,焊接接头的强度高于∏T3B板材的强度;显微组织观察发现焊缝中心形成了大量的针状马氏体组织;显微硬度试验中发现靠近∏T3B一侧的焊接接头熔合线附近由于晶粒长大,其硬度值较低。

In this paper, the 800MPa level Ti6AI4V and the 600MPa level ∏T3B titanium alloy plates were welded with the 2B welding wire by using the manual argon tungsten-arc welding. After welding the mechanical properties were tested, at the same time the microscopic structure test as well as the hardness of different areas of the welding joint was observed. The research result indicated that the fracture of tensile specimen happened in the ∏T3B titanium alloy plate, that was to say ： with the welding wire of lower intensity level, the strength of the welding joint was higher than theHT：3B titanium alloy plate because of alloying agent transition from Ti6Al4V. From the metallographic microscope, a lot of needle like martensite were found in the tissue of the welding seam center. The hardness of the area near the weld bond close to the ∏T3B plate was comparatively low in the hardness test. due to the crystal grain growth.