热喷涂对模具钢表面性能的改善与研究

Improvement and Study on Surface Properity of Arc Sparying Die Steel

通过电弧喷涂工艺在8Cr3模具钢表面制备了FeCrAl涂层。利用扫描电镜、能谱分析仪对涂层表面、截面形貌、元素进行分析,利用MH-3型显微硬度计对FeCrAl涂层的平均硬度进行测定;将试样静置于720℃的熔融ZL101A铝液30 min、1 h和2 h,比较各试样的熔损情况。结果表明:涂层与模具钢基体结合部位没有十分明显的界线,部分区域相互机械咬合,FeCrAl涂层内部粒子相互交错成波浪状堆叠,涂层整体组织致密;模具表面喷涂的FeCrAl涂层,其平均维氏硬度可达282.6 HV0.5;试样经电弧喷涂FeCrAl涂层处理后,随铝熔蚀时间的延长,熔蚀速率明显偏低。未喷涂处理的模具钢熔蚀后在界面附近形成了新相Fe2A15。

FeCrAl coating was prepared on the surface of 8Cr3 die steel through the electric arc spraying technology. The surface and cross section morphology, elements were analyzed by the means of SEM and EDS. The average hardness of the FeCrAl coating was tested by MH-3 microhardness tester. In order to compare the phenomenon of melts-loss, the sample was kept in the molten ZL101 A for 30 min, 1 h and 2 h, respectively. The results show that there is no obvious boundary in the combining site between the coating and substrate and there is mechanical occlusion in partial region of them. Particles in the interior of FeCrAl coating mutually intersect to wavy stack and the structure of the whole coating becames compact. The average Vickers hardness of the FeCrAl coating on the surface of mould reaches at 282.6 HV0.5. The melting rate of the mould steel evidently reduces with the extension of aluminum melting time, after the sample is modified by electric arc spraying technology. The die steel without the modification formes a new Fe2Al5 phase near the interface after it is melted.