Abstract: Cross wedge rolling process of 4Cr9Si2 was simulated by DEFORM software， and the influence of process parameters on surface spiral on cross wedge rolling of 4Cr9Si2 was analyzed. The results showed that the surface spiral was resulted from the variation of stress state which was generated in the process of rolling. As the forming angle increased， the depth of surface spiral increased. The surface spiral decreased after increasing of wedge tip fillet. Effect of stretching angle on the surface spiral was not obvious. When the area reduction decreased， plastic deformation was smaller and the surface spiral reduced. These simulated results were verified by experiments. The process parameters for a certain type of valve were determined to be α=32°，β=7.5°， R=12mm， when area reduction is 70.84%， and valves without surface spiral were experimentally achieved.

Key words: cross wedge rolling, 4Cr9Si2, numerical simulation, process parameters, surface spiral