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采用钨极手工氩弧焊机对Φ4.0 mm,Φ3.6 mm,Φ3.0 mm,Φ2.8 mm四个规格TC4丝进行焊接,焊接后再拉拔到Φ2.6 mm,变形量分别为57.8%,24.9%,19%,13.8%。对焊点和母材力学性能进行对比分析,结果表明,焊接后拉拔变形量为19%,13.8%时,试样均发生发生脆断,焊点处硬度值达到368.7 HV0.3,相比母材硬度310 HV0.3提高了18.9%;焊接后拉拔变形量为24.9%时焊点试样综合性能得以改善,没有发生脆断,但塑性较差,断后延伸率只有5.5%;焊接后拉拔变形量为57.8%时,焊点试样综合性能接近于母材一致,表现出良好的强度和塑性,抗拉强度为1060 MPa,断后伸长率为14%,断面收缩率为51%,显微硬度为311 HV0.3。这是因为焊接后经过一定变形量的热拉拔后,改善了焊缝脆化组织,粗大晶粒破碎、细化,提高了焊点处钛合金的力学性能。因此,要保证焊接后TC4丝材焊点的组织性能优异,焊接后拉拔工序应有足够的拉拔变形量。
Tungsten arc welding machines were used to weld four kinds of TC4 wires of Φ4.0 mm, Φ3.6 mm, Φ3.0 mm and Φ2.8 mm. After welding, they were drawn to Φ2.6 mm. The deformations were respectively 57.8%, 24.9%, 19%, 13.8%. The mechanical properties of the welding spot and the base metal were compared and analyzed. The results showed that when the drawing deformation was 19% and 13.8% after welding, the specimens were brittle and the hardness of the welding spot reached 368.7 HV0.3, The hardness of base metal 310 HV0.3 increased by 18.9%; after welding the drawing deformation amount was 24.9%, the comprehensive performance of the solder joint sample was improved, the brittle fracture was not occurred, but the plasticity was poor and the elongation after fracture was only 5.5% When the amount of drawing deformation is 57.8%, the comprehensive performance of the solder joint specimen is similar to that of the base metal, showing good strength and plasticity. The tensile strength is 1060 MPa, the elongation after fracture is 14% and the reduction of area is 51% , Microhardness of 311 HV0.3. This is because the welding after a certain amount of deformation of the hot drawing, to improve the weld brittle tissue, coarse grains broken, refined, and improve the mechanical properties of the titanium alloy at the weld. Therefore, to ensure that welding TC4 wire joints excellent organizational performance, after drawing the drawing process should have enough drawing deformation.