厚板Ti-6Al-4V磁控窄间隙TIG焊接头性能

摘要

The narrow-gap TIG welding with magnetic control system was used to weld the Ti-6A1-4V alloy of 56 mm in thickness. The mechanical properties of weld bead were tested including tensile strength, impact toughness, and hardness. The results shows that the tensile strength value is higher than that of the filler metal due to the meshing strengthened effect. The stress distribution along the through-thickness direction of the joint determines the highest tensile strength and toughness value in the area nearby the welding center line. The welding stress between surface layer and interlayer makes the tensile strength and toughness value decreased. The surface layer has the medium value without welding stress. The highest hardness value appears in the fusion line at the same position on depth because of the acicular α'.%对56 mm厚Ti-6Al-4V进行了磁控窄间隙TIG焊试验,对接头的力学性能进行分析,其中包括拉伸性能、冲击性能及硬度.结果表明,焊缝的强度高于填充金属的原始性能值,这是通过针状组织的啮合强化效果来实现的.而由于焊缝横截面沿厚度方向上的内应力分布导致后焊侧的中心线附近的强度及韧性明显提高.介于表层及中心层之间由于拉应力的存在而导致其强度及韧性较差,而表面层由于没有内应力的存在而使得其强度和韧性介于前二者之间.同一位置深度上,焊接热影响区熔合线附近的硬度最高.这是由于大量蓝网状分布的针状α'相存在的原因.