Abstract: The influences of the factors of a two roll cross piercing process on quality of GH131 alloy shells and on piercing forces are studied and the main factor effecting shell quality is found to be roll speed.Holes would appear in shells with lower speed and laminations would appear with higher the speed but these holes and laminations in shells of GH131 alloy can be completely eliminated if the roll speed is reduced to the level below the critical speed causing the above defects with larger advancing angle and rational heating temperature and deformation.