球墨铸铁激光表面改性的研究

LASER SURFACE MODIFICATION OF NODULAR IRON

文中探讨了激光对球墨铸铁表面熔化处理,以及表面合金化对其钝化性能和耐腐蚀性能的影响。实验结果表明,激光处理后球铁表面产生的渗碳体和奥氏体细晶区,可大幅度降低球铁的腐蚀速度,使合金具有很好的钝化倾向(在5％H_2SO_4和5％HNO_3溶液中)。在激光合金化条件下,合金元素Cr和Si的作用不同,Cr可促进球铁钝化提高耐腐蚀性,而Si的作用则相反。

The effects of laser surface treatment and laser alloying on passivity and corrosion resistance of nodular iron have been investigated. Experimental results show that the fine grain zone of cementite and austenite on the specimen surface treated by laser can greatly reduce corrosion velocity of nodular iron and enable the nodulal iron to obtain better passivity (in .5% H2SO4 and 5% HNO3 solution). The effect of Cr on corrosion resisance is different from that of Si under laser alloying. The addition of Cr can promote passivation and then enhances corrosion resistance of nodular iron, but Si has a contrary effect.