Bearing steel full name is rolling bearing steel, has the high compressive strength and fatigue limit, high hardness and high wear resistance and a toughness, its quench-hardening ability, sulfur and phosphorus very strict control, is a kind of high quality steel, can make do with touch cold steel. Proportion: 7.81
(a) bearing steel forging temperature
(1) in the beginning temperature: 1150 (1120) at satin temperature: 850 (800) degrees.
(2) before forging cleared surface defects, try to preheat the rapid heating after.
(3) temperature processing, should avoid to 200 ~ 400 degrees blue brittle area. The hot working, should avoid to enter crisp high temperature area (more than 1250). Should try to avoid heat into the brittle area (800 ~ ~ 950 degrees).
(2) after forging heat treatment
(1) after heat treatment in advance, forging-(ball annealing)---eventually heat treatment (low temperature quenching and tempering)
(2) ball annealing objective: to reduce hardness, facilitate processing, to prepare for the quenching.
Ball annealing process: heating to 750 ~ ~ 770 degrees, heat preservation for a certain length of time and slow cooling to 600 degrees in the cold air.
(3) all kinds of bearing steel quenching and tempering and YingDuBiao low temperature
GangHao quenching temperature quenching and tempering HRC low temperature medium hardness
GCr6 800 ~ 820 water or oil 150 ~ 170 62 ~ 64
GCr9 800 ~ 830 water or oil 150 ~ 170 62 ~ 64
GCr9SiMn 810 ~ 820 water or oil 150 ~ 160 62 ~ 64
GCr15 820 ~ 846 oil 150 ~ 160 62 ~ 64
GCr15SiMn 800 ~ 840 oil 150 ~ 170 62 ~ 64
(3) quenching and hardening medium
(1) quenching color (experience) white the most hard and brittle, yellow hard, tough blue soft and toughness.
(2) quenching media
A water: general temperature not more than 40 degrees, can not have oil, soap, etc impurities.
B salt and alkali solution: the water and five percent ~ 10 of salt or alkali.
Salt solution the cooling speed is ten times the water, high hardness and even, but organization stress is great, have certain rust role. Temperature less than 60 degrees.
Alkali solution (global solution on sex) corrosive, the range of small.
C oil: including the motor oil, DingZiYou, transformer oil, diesel, etc. Can reduce the deformation and cracking. Not applicable carbon steel. Oil temperature: in 60 ~ ~ 80 degrees, is highest do not exceed 100 ~ 120 degrees.
(4) the tempering temperature
Bearing steel low temperature firing back. Temperature: 150 to 250 degrees. But in keeping the high hardness and high wear resistance, under the premise of reduce stress and brittleness, lest when using open or an early damage. Hardness HRC: 58 ~ ~ 64




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