铜基微晶钎料真空钎焊25Cr3MoA/YG6

VACUUM BRAZING OF 25Cr3MoA/YG6 USING CuBASED MICROCRYSTALLINE BRAZING ALLOY

应用Cu 11%Sn-2%Ni微晶钎料对25Cr3MoA钢和YG6硬质合金进行了真空钎焊,观察了接头组织形貌,建立了钎料层/母材原子互扩散模型,定量分析了焊接区合金元素的分布特征,并在专用仪器上测试了接头的剪切强度.结果表明:使用铜基微晶钎料钎焊25Cr3MoA和YG6,润湿性和铺展性良好,形成的钎缝饱满致密,接头钎着率高;钎缝组织以铜固溶体为主相,其问分布着Cu_3Sn相、富Ni的Cu9NiSn_3相以及少量的γ-Fe相.铜原子从钎缝向母材的扩散深度约为25μm.应用铜基微晶钎料可实现25Cr3MoA与YG6的真空扩散钎焊连接,接头剪切强度较高,达169MPa.

The vacuum brazing of 25Cr3MoA steel and YG6 cemented carbide was conducted by using a Cu-11%Sn-2%Ni microcrystalline brazing alloy. The microstructure of joint, behavior of atom mutual diffusion and distributions of alloy elements within the joint were analyzed. The shearing strength of joints was tested by using a special tester. The experimental results show that the Cu-based microcrystalline braze performs an excellent wettability and spreadability during vacuum brazing of 25Cr3MoA/YG6, and the brazing seam obtained is permeated soundly, thus the joint has a higher brazed ratio; the microstructure of brazing seam consists mainly of Cu solid solution, Cu3Sn phase, Cu9NiSn3 phase and a few γ-Fe phase. The diffusion range of Cu atoms from brazing seam to base metals reaches to 25 μm. Therefore, the diffusion brazing of 25Cr3MoA and YG6 has been realized and the shearing strength of joint is high up to 169 MPa.