薄壁结构焊接接头CTOD试验分析

设计测试薄壁结构平面应力断裂韧性的三点弯曲测试试样,应用于GH4169焊接接头CTOD测试试验。采用光学金相显微镜和扫描电镜观察分析各试样的裂纹扩展形貌和断口形貌。依据BS7448标准的规定分析CTOD测试过程有效性。结果表明,采用设计三点弯曲试样进行的GH4169焊接接头CTOD测试过程是有效的;GH4169母材的断裂韧性较好,裂纹为延性起裂特性;GH4169焊缝和熔合区的断裂韧性较差,裂纹为脆性起裂特性。

Analysis on CTOD Test of Thin-Walled Structure Welding Joint

A special kind of three point bend specimen is designed for the plane-stress fracture toughness test of thin-walled structure, which is used as the specimen in the CTOD test of Inconel 718 welded joint. Metallographic microscope and stereoscan are used to oberve the crack propagation pattern and fractography for all specimens respectly. Validity check is made in the light of the relative specification of BS7448 code. The results show that the CTOD test of Inconel 718 welded joint which uses the special kind of specimen is valid. The base metal of Inconel 718 welded joit has a good fracture toughness, in which the character of crack start is ductible. However, the welded bead and fusion area of Inconel 718 welded jiont have bad fracture toughness, in which the character of crack start are brittle.