Aluminium Window Door Hardware

For example, for a 20CrMnTiH gear, the forging weight is 2.1kg. After forging, the air-cooling has uneven structure and high hardness. The cooling can be controlled in a steel box with thermal insulation material. That is, normalizing with the waste heat of forging, the forging is reduced from 900 degree to 700 degree in about 1h, and then slowly cooled from 700 degree to 660 degree in about 3h, and finally the forging is quickly cooled out of the incubator to obtain a mixed structure of ferrite and pearlite, and the hardness is It is 156HBW162HBW, which is lower than the air-cooled hardness after forging, and has a small hardness fluctuation range, which is convenient for cutting and processing. More importantly, it is controlled to cool to room temperature after forging and then carburized at 930 degree and oil quenched at 790 degree to obtain a grade of 9 Uniform austenite grains and no coarse grain heritability, which is ready for future heat treatment.

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