合金元素对Q345钢表面Cu基熔覆层组织及性能的影响

为了提高Q345钢的表面耐磨性以及得到性能优良的铜/钢复合材料，设计了两种Cu-Ni-Cr-C系金属粉芯焊丝，采用GTAW熔覆方法制备了两种铜基熔覆层，并利用SEM、EDS、硬度和摩擦磨损试验对熔覆层的组织和性能进行了研究。试验结果表明:两种熔覆层的基体组织均为Cu-Fe-Ni-Cr固溶体，并由于成分的差异在液相分离作用下产生了不同的析出相。其中，1#熔覆层的析出相主要为粗大的富Fe相，2#熔覆层的析出相以细小的富Cr相为主。两种熔覆层均与Q345钢基体达到了冶金结合，Cu、Cr、Ni、Fe元素在界面处均发生了一定的扩散。另外，得益于固溶强化和第二相强化作用，两种熔覆层的硬度均接近Q345钢基体，且2#熔覆层的硬度高于1#熔覆层，这与析出相的种类和尺寸有关。两种熔覆层均表现出了较好的耐磨性，其中2#熔覆层的摩擦系数略低于1#熔覆层，且磨损量与1#相比大大减少，表明其耐磨性更优。

Effects of Alloying Elements on Microstructure and Properties of Cu-based Cladding Layers on Q345 Steel

In order to improve the surface wear resistance of Q345 steel and obtain copper/steel composite materials with excellent properties, two types of Cu-Ni-Cr-C metal powder-cored wires were designed, and two Cu-based cladding layers were prepared by GTAW cladding method. The structure and properties of the cladding layers were studied by SEM, EDS, hardness and wear tests. The test results show that the matrix structure of the two cladding layers is Cu-Fe-Ni-Cr solid solution, and different precipitate phases are produced under the action of liquid phase separation due to the difference in composition. The precipitation phase of 1# cladding layer is mainly coarse Fe-rich phases, and the precipitation phase of 2# cladding layer is mainly fine Cr-rich phases. The two kinds of cladding layers achieved metallurgical bonding with the Q345 steel matrix, and Cu, Cr, Ni, Fe elements all diffused at the interface to a certain extent. In addition, thanks to the solid solution strengthening and the second phase strengthening, the hardness of the two cladding layers is close to that of the Q345 steel matrix, and the hardness of the 2# cladding layer is higher thanthat of the 1# cladding layer, which is related to the type of precipitation related to size. Both cladding layers showed good wear resistance. The friction coefficient of the 2# cladding layer was slightly lower than that of the 1# cladding layer, and the wear amount was greatly reduced compared with that of the 1# cladding layer, indicating its wear resistance is better.