1.Existing process of hot die forging (cross forging)
Hot die forging of driving spiral bevel gear blank is the earliest forming process for the production of driving gear blank. It is by placing the blank horizontally in the axial direction and putting it into the die for vertical forging after extrusion, also known as cross forging. This process requires large equipment tonnage, serious noise pollution and a large amount of flash waste, which has long been replaced by more advanced processes.
Disadvantages: serious oxidation decarburization, large surface defects of forgings, thick machining allowance needs to be reserved, and raw materials are wasted.
2.Vertical pre forging + horizontal final forging
The process of horizontal final forging after vertical pre forging is also a relatively backward forming process, because at present, the production of shaft forgings has basically been replaced by more advanced forging processes such as roll extrusion and cross wedge rolling. Compared with the existing process of hot die forging, there is less one roll extrusion process.
Disadvantages: forging hammer pre forging is forging with striking force, with high vibration and noise and poor working environment.
3.Warm forging (drawing blank → upsetting)
In the process, when the forging temperature is lower than 1000 ℃, it belongs to warm forging. When the forging temperature is higher than ℃, it belongs to hot forging. Hot forging will cause serious oxidation and decarburization. In order to avoid surface defects of forgings, it is necessary to leave machining allowance thicker than that of warm forging process, so it wastes materials than warm forging.
Advantages: less oxidation and decarburization, improve the quality of forgings, and achieve the effect of energy saving and material saving.
4.Cross wedge rolling
Due to the special defects of cross wedge rolling, conical depressions deeper than will be formed at both ends of the workpiece after rolling. Therefore, if the workpiece is formed directly by rolling and there is no subsequent process, a section of process surplus larger than will be left at both ends, and the surplus will be cut off when the forming is completed, resulting in material waste. Especially when the finer part is rolled in the middle and the coarser part is rolled at both ends, the waste is more serious.
Advantages: it has large output, high efficiency, high forging quality, material saving and energy saving.
5.Cross wedge rolling → upsetting forming
This process is the combination of cross wedge rolling and die forging. The combination of the two can inherit the advantages of high precision and high production efficiency of cross wedge rolling without cutting off the head, which can eliminate the influence of head end face depression. Therefore, the utilization rate of materials is higher than that of cross wedge rolling.
Advantages: rolling in pairs, connecting the cone and tail of forgings, small notch surplus, high precision and production efficiency, small equipment investment, and the concave part of the end face can be used during upsetting without reserving process surplus blocks, so as to save a lot of materials.