论文部分内容阅读
采用热喷涂方法在Q235钢表面预置Ni25涂层,研究了激光重熔过程中工艺参数对熔覆层组织的影响;用光学显微镜(OM)观察了涂层横截面的显微组织。结果表明:经过激光重熔后的熔覆层与基体之间形成了良好的冶金结合,其组织组成物包括γ-固溶体,硼化物、碳化物+γ-固溶体的共晶,初晶及共晶的合金渗碳体。在其他工艺参数不变的条件下,随扫描速度的增大,熔覆层组织变得细小、均匀;随激光功率的增大,熔覆层组织变化由块状组织到细小的树枝晶组织,再到粗大的胞状晶组织。
The thermal spraying method was used to pretreat Ni25 coating on the surface of Q235 steel. The influence of the technological parameters on the microstructure of the cladding layer during laser remelting was studied. The microstructure of the coating cross section was observed by optical microscope (OM). The results show that a good metallurgical bond between the cladding layer and the substrate after laser remelting has been achieved. The microstructure of the microstructure consists of γ-solid solution, boride, eutectic carbide and γ-solid solution, primary and eutectic Alloy cementite. Under the same process parameters, with the increase of scanning speed, the microstructure became fine and uniform. With the increase of laser power, the microstructure of cladding layer changed from massive structure to fine dendrite structure, Then to the coarse cell crystal structure.