Straight bevel bevel gear is a component of automobile differential, which is made of low-carbon alloy steel. Its normal warm forging temperature range is 800 ~ 850 ℃. Warm precision forging of straight bevel gear: the tooth shape of the forging is net forming, which is basically close to the forming accuracy of cold forged gear. Compared with the cold forging process, the non blank annealing and surface phosphorus saponification lubrication process can shorten the product production circulation cycle by 3 ~ 4 days, which is in line with the current concept of green manufacturing.
In order to realize the normal operation of a complete warm precision forging automatic line, many problems need to be solved in the process. The following takes the warm precision forging of half shaft gear of a main engine factory as an example to analyze some conditions and solutions encountered in the production process. The gear part diagram is shown in Figure 1.
The gear forging adopts the closed flash free forging process, which is precision forged by one fire and two forging. The shape of the forging blank is shown in Figure 2. The layout of the gear forging production line is shown in Figure 3. The forging equipment is two 630t electric screw presses, equipped with automatic feeding system + medium frequency heating furnace + three robots + graphite spraying system. The production process is as follows: blanking – flat head, chamfering – heating – precoating graphite – heating – pre forging – final forging – controlled cooling – shot peening – machining – heat treatment – finishing – cleaning and packaging. Pre coated graphite can effectively control the surface oxidation and decarburization of raw materials and improve the surface quality of forgings.