Effect of remelting welding on porosity and mechanical properties of TC4 titanium alloys

YANG Sida; LIU Lian; ZHAO Duo; WU Xiaowei

doi:10.7512/j.issn.1001-2303.2020.05.04

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Effect of remelting welding on porosity and mechanical properties of TC4 titanium alloys
Vol. 50, Issue 5, Pages: 21-26(2020)
DOI： 10.7512/j.issn.1001-2303.2020.05.04

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YANG Sida, LIU Lian, ZHAO Duo, et al. Effect of remelting welding on porosity and mechanical properties of TC4 titanium alloys. [J]. 50(5):21-26(2020)
DOI：

YANG Sida, LIU Lian, ZHAO Duo, et al. Effect of remelting welding on porosity and mechanical properties of TC4 titanium alloys. [J]. 50(5):21-26(2020) DOI： 10.7512/j.issn.1001-2303.2020.05.04.

摘要

针对TC4钛合金接头内部易产生气孔缺陷的问题,开展了重熔焊对接头气孔消除作用的研究。研究表明,不同重熔焊电流均能得到外观成形良好的焊缝,X射线探伤结果显示,重熔焊能够有效减少气孔数量,气孔尺寸越大消除作用越显著,且增大重熔焊电流有利于提高气孔消除率。拉伸试验表明,R,70,（重熔焊电流为70 A的接头,下同）、R,80,重熔焊接头的抗拉强度与母材相当,硬度在母材区获得最低值,这主要与熔合区中存在的针状马氏体α′相有关。而R,90,接头抗拉强度较高但延伸率显著降低,且在熔合区生成了粗大的块状初生α,m,相,从而使熔合区成为整个接头的薄弱环节。

Abstract

To solve the problem of porosity in TC4 titanium alloys,the effect of remelting welding on the elimination of joints porosity was studied. Results showed that favorable formation can be obtained by different remelting current,and the results of X-ray inspections also showed that remelting welding can effectively reduce the number of pores.The larger the pore size was,the more significant the elimination effect was. Besides,increasing the current of remelting welding was beneficial to increase the porosity elimination rate. Tensile tests indicated that the tensile strength of R,70, and R,80, remelting welded joints were equivalent to the base metal,while the base metal area obtained the lowest hardness of the joints,which mainly related to the acicular martensiteα′ phase in the fusion zone. R,90, joints got higher tensile strength but lower elongation,and generated massive primaryα M phase in the fusion zone,which made fusion zone the weak link of the whole joint.