Abstract: Rolling radius of formed part in the rolling procedure of cross wedge rolling is one of the basic parameters for die design and process analysis, which reflects the relationship of relative motion between roll and formed part, so it plays an important role in roller shape curve design of dies for shafts with noncircular cross-section such as the camshaft of engine. By rolling experiment, the variation law of rolling radius during the rolling process is obtained, and the influence rules of technical parameters are achieved. The results show that the rolling radius of formed part is larger than the size of original billet and gradually decreases with rolling process at the knifing stage, and keeps stable during the period of stretching. At the stage of shaping, the rolling radius decreases gradually as the elevation of the mould forming surface. And it basically equals to the final dimension of formed part in the finishing stage. The rolling radius of rolled piece increases with the increment of the tool stretching angle and forming angle. Influence of area reduction is relatively complicated. The rolling radius increases as the area reduction increased at first. When the area reduction raises certain value, it reduces with the rise of area reduction. The diameter of billet shows that the greater the diameter radio of roll to formed part is, the closer the rolling radius to the inner side of original billet size will be. It is found that the influence of rolling temperature on the rolling radius can be ignored, but the condition of notch on the mould has significant effect.

Key words: Cross wedge rolling, Relationship of relative motion, Rolling radius of formed part, Variation law