中镍铬无限冷硬铸铁轧辊激光表面强化

本文采用在铸铁轧辊表面上激光熔化预置的合金粉末来改善铸铁轧辊的表面性能.使用金相、扫描电镜和显微硬度计对激光熔化区的显微组织和硬度进行了测试表征.结果表明,激光熔化区与基体形成了冶金结合.由于激光的快速加热和快速冷却造成熔化区的组织细化.激光处理区的硬度由于晶粒细小和强化相的存在而得到提高.经450℃×48h高温回火处理后,激光熔化区的硬度几乎不发生改变.

Laser Surface Strengthening of Medium-Ni-Cr Infinite Chilled Cast Iron Roller

The paper presents laser surface melting of preplaced powder in order to change the surface layer properties of a medium-Ni-Cr infinite cast iron roll. Metallographical(OM and SEM),as well as microhardness investigations are presented as an illustration showing the benefits of laser application in modification of cast iron roll surface layer properties. The results showed that the modified coating combines metallurgically with the substrate. The fine microstructure of the melted zone were attributed to high cooling rates due to the short interaction time with the laser and relatively small volume of the melted materials. An increase in microhardness of the laser treated zone after laser melting may be attributed to fine precipitates formed in melted zone and to the transformation of retained austenite. After tempering 48h treatment under 450℃, the hardness almost didn't varied.