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通用汽车公司的Hydramatic分公司采用冷镦热挤联合工艺制造小模数行星齿轮的毛坯。过去该公司是采用退火的热轧棒材切削成齿轮毛坯,棒材直径为34.6毫米,每一只毛坯需要消耗钢材0.2公斤。同时还需要大量的六轴自动车床。可是采用了冷镦热挤联合工艺以后,每只毛坯只需要0.11公斤钢材,材料消耗降低了45％。本来这种零件是可以用冷挤工艺制造的,但是,由于其材料是高炭钢,冷挤方法就不适用了。反挤压在常温下一般只适用于含炭量不超过0.35％的钢。虽然有一些含炭量更高的零件也成功地进行了冷挤压,但其原材料都要经过长时间的、昂贵的球化退火,模具寿命不长,而且由于压挤过程中的冷硬作用,还经常需要在工序之间
The Hydramatic division of General Motors uses a cold-heading hot-extrusion process to make small module planetary gears. In the past, the company used annealed hot-rolled bars to cut gear blanks with a bar diameter of 34.6 mm and each blank requiring 0.2 kg of steel. At the same time also requires a large number of six-axis automatic lathes. However, with the cold heading hot extrusion process, only 0.11 kg of steel per blank is required and the material consumption is reduced by 45%. Originally, this part could be made by cold extrusion, but because of its high carbon steel, cold extrusion did not work. Extrusion at room temperature generally only applies to carbon content of not more than 0.35% of the steel. Although some of the higher carbon content of the parts have also been successfully cold extrusion, but the raw materials have to go through a long, expensive ball annealing, mold life is not long, but also because of the chilling effect of the crushing process , Often also need to be between processes