High carbon bearing steel forging

The full name of bearing steel is called rolling bearing steel, which has high compressive strength and fatigue limit, high hardness, high wear resistance and certain toughness, good hardenability, strict control of sulfur and phosphorus, and is a kind of high-quality steel. Do cold to touch the steel. Specific gravity: 7.81

(1) Bearing steel forging temperature

(1) Initial forging temperature: 1150 (1120) final satin temperature: 850 (800) degrees.

(2) Remove surface defects before forging, and heat them as soon as possible after preheating.

(3) When processing at a temperature, the blue-brittle area of ​​200 to 400 degrees should be avoided. When hot working, avoid entering high temperature brittle areas (greater than 1250). Try to avoid entering the hot brittle zone (800 ~ 950 degrees).

(2) Post-forging heat treatment

(1) After forging --- pre-heat treatment (spheroidizing annealing) --- final heat treatment (quenching + low temperature tempering)

(2) Spheroidizing annealing purpose: reduce hardness, facilitate processing, and prepare for quenching.

Spheroidizing annealing process: heating to 750 ~ 770 degrees, holding for a certain period of time, cooling slowly to 600 degrees below air cooling.

(3) Various bearing steel quenching + low temperature tempering and hardness table

Steel quenching temperature and quenching medium low temperature tempering hardness HRCGCR6800～820 water or oil 150～17062～64GCR9800～830 water or oil 150～17062～64GCR9SIMN810～820 water or oil 150～16062～64GCR15820～846 oil 150～16062～64GCR15SIMN800 ~840 oil 150～17062～64

(3) Quenching and quenching media

(1) Hardening color (experience) White is the hardest and brittle, yellow hard and tough, blue soft and tough.

(2) Quenching medium A water: the general temperature does not exceed 40 degrees, and there must be no oil, soap and other impurities. Aqueous solution of B salt and alkali: add 5-10% salt or alkali in water. The cooling rate of the salt solution is ten times that of water, and the hardness is high and uniform, but the tissue stress is large and there is a certain rusting effect. The temperature is less than 60 degrees. The alkali solution (caustic aqueous solution) has high corrosivity and a small adaptability range. C oil: including oil, spindle oil, transformer oil, diesel and so on. It can reduce deformation and cracking. Carbon steel is not applicable. Oil temperature: 60 to 80 degrees, the maximum is not more than 100 to 120 degrees.

(four) tempering temperature

Bearing steel is tempered at low temperature. Temperature: 150 to 250 degrees. It can reduce internal stress and brittleness while maintaining high hardness and high wear resistance to avoid cracking or premature failure during use. Hardness HRC: 58 ~ ~ 64.