45钢激光表面铬合金化的制备工艺

Preparation process of 45 steel laser surface chromium alloying

为提高注塑机螺杆性能,在45钢表面预置0.15mm的铬合金化粉末,采用激光合金化方法在基体表面制备铬合金化层,利用正交试验法优化激光铬合金化工艺参数并对最佳参数下的合金化层性能和组织进行检测。结果表明:随着激光功率的增加,铬合金化层的硬度先增大后减小;随着激光扫描速度的增加,铬合金化层的硬度逐渐降低;随着激光搭接率的增大,铬合金化层的硬度先增大后减小;预涂层厚度为0.15mm的铬合金化层最佳激光合金化工艺参数为:激光功率为3.1kW,激光扫描速度为800mm·min^-1,激光搭接率为30%。经该工艺处理后的铬合金化层厚度约为1.2mm,其中铬合金化区厚度约为0.8mm,平均硬度大约为583.6HV0.1,组织为Fe-Cr、CrxFey等固溶体,热影响区厚度约为0.4mm,硬度从572HV0.1到230HV0.1呈梯度分布,组织为针状马氏体和少量残留奥氏体。

To improve the performance of screw rod of injection molding machine,0.15mm chromium alloy powders were prepared on the surface of 45steel by laser alloying method.Orthogonal test was used to optimize the process parameters of laser chromium alloying and to test the properties and structure of the alloying layer under the optimal parameters.The results show that with the increase of laser power,the hardness of chrome-alloying layer increases and then decreases gradually.With the increase of laser scanning speed,the hardness of chromium alloying layer decreases gradually.As the laser bond of preeoating increases,the hardness of the chromium alloying layer increases and then decreases gradually.The optimal laser alloying process parameter for a chromium alloying layer with a precoating thickness of 0.15mm is laser power 3.1kW,laser scanning speed 800mm·min-1,laser bond 30%,respectively.The thickness of the chromium alloying layer is about 1.2mm,of which the thickness of the chromium alloying area is about 0.8ram,the average hardness is about 583.6HV0.1,the microstructure is solid solution phases such as Fe-Cr,CrxFey,the thickness of the thermal influence area is about 0.4ram,the hardness is of a gradient from 572HV0.1to 230HV0.1,and the microstructure is needle-like martensite and a little residual austenite.