激光熔覆高铬铸铁组织和硬度的研究

针对高铬铸铁铸造组织粗大,强韧性差,容易开裂的问题,进行了高铬铸铁粉末激光熔覆实验,对熔覆层的显微组织和硬度等性能进行了检测与分析,研究了不同扫描速度对熔覆层显微组织和硬度的影响,分析了多道搭接区和多层堆积区熔覆层显微组织的演变规律,揭示了多层堆积横截面的硬度分布规律。研究结果表明:通过激光熔覆可以获得晶粒细化、组织致密、无裂纹与气孔等缺陷、硬度高(可达580 HV0.2)的高铬铸铁熔覆层。将该工艺应用到零件表面强化领域,将大大提高零件的性能和使用寿命。

Research on microstructure and hardness of high-Cr cast iron made by laser cladding technology

Aiming at the flaws of high chromium cast iron, such as coarse microstructure, low obdurability and easy to crack, the experiments of laser cladding were made. High-chromium( Cr) cast iron powder was used as cladding material. The microstructure and hardness of laser cladding layer were studied. The effect of different scanning speed on microstructure and hardness was researched. The laws of overlapping and building-up were analyzed. The hardness distribution curve of laser building-up cladding was also tested. The results indicate that high-Cr cast iron cladding layer has better properties such as minute crystals, high density, no crack, no gas cavity and high hardness( 580HV0. 2). Using laser cladding, the good wear layer would be made on the surface of parts which would greatly increase the useful life of parts. [ABSTRACT FROM AUTHOR]