Abstract: To improve wear resistibility of inter surface for thick oil pump shell made form cast iron that will increase the time of pump itself directly.The wear resistibility of grey cast iron HT200 is increased through hardening the surface of cast iron which is obtained as remelting it with tungsten inert shielded gas arc.The effect of arc current and melting rate on the microstructure and wear resistance is studied.The results are compared with those of WC electrode hardfacing for cast iron with chilled treating and proved that remelting hardening principle is much better and cheaper technique than the others.