QCr0.5中间层与表面激光改性后的40Cr钢超塑性连接

Superplastic solid state welding of QCr0.5 copper alloy interlayer with 40Cr steel after surface laser modification

经激光表面淬火预处理后的40Cr钢,进行预置QCr0.5中间层的超塑性焊接研究。结果表明,经激光淬火预处理后的40Cr钢与QCr0.5中间层待焊接面经仔细清洗,在预压应力56.6MPa、初始应变速率2.5×10-4s-1、焊接温度750～800℃的条件下,经120～180s短时压接,即可实现二者的超塑性连接,接头强度达QCr0.5母材强度,胀大率不超过6%。当预置中间层厚度小于2.5mm时,接头强度明显高于40Cr/QCr0.5超塑性焊接的。在焊接过程中,接头区界面两侧发生了明显的原子互扩散;QCr0.5铜合金发生了超塑性流变。

The welding surface of 40Cr steel was ultra-fined by laser quenching, and then the superplastie solid state welding process between 40Cr steel and QCr0.5 copper alloy interlayer was conducted. The experimental results show that with the sample surface of 40Cr steel after laser quenching and QCr0.5 copper alloy interlayer carefully cleaned, under the pre-prcssing stress of 56.6MPa, initial strain rate of 2.5 × 10^-4 s^-1 and at the welding temperature of 750 - 800℃ , the superplastic solid state welding is successfully performed in 120 - 180s. The strength of the joint is up to that of QCr0.5 base metal and the expansion rate of the joint doesn＇t exceed 6%. The strength of 40Cr/QCr0.5/40Cr joint with less than 2.5mm QCr0.5 interlayer is obviously higher than that of 40Cr/QCr0.5 joint. In welding process, atoms in two sides of the joint interface have obviously diffused each other, and superplastic deformation of the QCr0.5 copper alloy occurs.