TC4厚壁管全位置PAW工艺及接头性能分析

介绍了一种适合TC4钛合金厚壁管的等离子弧焊接新工艺，通过对工艺参数分区控制和优化匹配，实现了钛合金管道全位置优质焊接.采用光学显微镜、扫描电镜以及显微维氏硬度仪分别对特征位置焊接接头的显微组织、断口形貌以及显微硬度进行表征.结果表明，特征位置接头焊缝区及热影响区显微组织均主要由网篮状α'相、针状α相以及粗大β相组成；接头拉伸性能良好，拉伸试样均断裂于母材处；冲击试样的断裂形式为韧性断裂；焊缝区及热影响区硬化区的硬度值高于母材.

All-position plasma arc welding process for thick TC4 tube and mechanical properties of welded joints

A new plasma arc welding process for thick-walled TC4 titanium alloy tube was investigated. All-position high-quality welding joints of titanium alloy were achieved through parameters optimization. The microstructure, fracture morphology and microhardness of the welded joints at ordered locations were characterized by optical microscopy, scanning electron microscopy and micro Vickers hardness tester. The results reflected that the microstructure of the weld metal and the heat-affected zone of the characteristic joint were mainly composed of basket-shaped α' phase, needle-like α phase and coarse β phase. The tensile fractures of specimens was occurred at base metal, revealing well tensile properties. The fracture morphology of the impact specimens was ductile fracture. The hardness of weld metal and heat affected zones was higher than that of base metal, respectively.