Improvement of Wear Resistance of Cr-Mo Casting Steel to Increase It's Working Lifetime

The aim of this article is to study the effect of thermal treatment and adding chromium, during the casting, on mechanical and wear behavior of modified Cr-Mo casting steel alloy. Comparison of numerical simulation, which was done by Procast software, with practical results showed that the places which fractures happened, are dependent on hot and chill zones in the casting parts. Therefore, the casting needs to heat treat to eliminate thermal residual stresses and metallurgical stresses. Results of the optical and electron microscopy, hardness, impact and tensile tests in order to studying the wear properties of main and modified specimens showed that adding chromium and heat treatment cycle with controlled cooling rate to obtain superfine pearlitic structure, present the best wear resistance by increasing strength. This structure could improve the lifetime of the castingup to 5000 hours.