Warm forging of helical gear is a kind of plastic forming process with less and no cutting developed on the basis of cold forging. Its deformation temperature is generally considered to be in the temperature range above room temperature and below recrystallization temperature. The purpose of using warm forging process is to obtain precision forgings. The advantage of warm forging is that it can improve the accuracy and quality of forgings without the forming force as large as cold forging. The application of warm forging process of helical gear is closely related to forging material, forging size and forging complexity. Generally speaking, small precision die forgings of low carbon and low alloy steel with less complex shape can be formed by cold forging process; For medium and small carbon steel precision die forgings with complex shape, cold forging method is difficult to solve the forming problem, or if the cost of cold forging process is high, warm forging can be used.
Through the analysis of the forming process of driving helical gear, it can be seen that if the forging temperature is considered, warm forging will be the first choice of shaft forgings. In terms of material utilization rate, compared with the forging production technology of driving helical gear of automobile rear axle, the material utilization rate of driving helical gear produced by open die forging (cross forging) is 78.5%; The material utilization rate of drawing closed die forging (vertical forging) is 89.76% in hot forging and 86.88% in warm forging; The utilization rate of hot forging materials in cross wedge rolling, warm forging materials and closed die forging (vertical forging) materials in cross wedge rolling is 91%.
Through the analysis and comparison of various processes, it can be concluded that in the production of shaft parts at home and abroad, due to the characteristics of high material utilization, high production efficiency and good forging quality, the combination of cross wedge rolling and die forging process should be preferred.