热输入对感应重熔Ni60合金涂层组织与性能的影响

Influence of Heat Input on Microstructure and Properties of Ni60 Alloy Coating by Induction Remelting

采用氧乙炔火焰喷涂技术在45圆柱钢基体上制备Ni60合金涂层,然后在不同的加热功率条件下对涂层进行中频感应重熔处理。通过扫描电镜、能谱仪、显微硬度计和磨损实验机等研究了热输入对重熔涂层的组织结构、元素分布、显微硬度及耐磨性能的影响。结果表明:当加热功率为21 kW时,涂层与基体在界面处为机械结合,涂层孔隙多、组织疏松;随着加热功率增大至28 kW,涂层和基体间形成冶金结合,组织致密、均匀,界面处部分元素扩散迁移后呈梯度分布形式;加热功率继续增大至35 kW时,界面处形成的冶金白亮带变宽,但涂层表面出现合金流淌现象、表面凹凸不平。热输入变化对重熔涂层截面显微硬度及表面耐磨性产生了明显的影响。加热功率为28 kW的重熔涂层的显微硬度、耐磨性最好。

Ni60 alloy coating on 45 cylindric steel was prepared by oxyacetylene flame spraying technology.The coating was remelted by medium frequency induction remelting under different heating powers.The effects of heat input on the microstructure,element diffusion,microhardness and wear resistance of the remelting coating were studied by scanning electron microscope,energy dispersive spectroscopy,microhardness tester and tear testing machine.The results show that,when the heating power is 21 kW,the coating forms mechanical bonding with substrate in the interface,the coating have more porous and the structure is loose.As the heating power increases to 28 kW,the coating and matrix forms metallurgical bonding,then the microstructure is fine and homogeneous.And some elements in the interface present gradient distribution after the diffusion and migration.As the heating power increases to 35 kW,the metallurgical white band forming at the interface becomes wider.But the surface of the coating generates alloy flow phenomenon and its surface is uneven.The change of heat input has obvious influence on the section microhardness and surface wear resistance of the remelting coating.The microhardness and wear resistance of the remelting coating under 28 kW heating power is best.