Hot-rolled or cold-rolled (cold drawn) of seamless steel pipe, bearing steel bearing rings used for the manufacture of ordinary steel tube outer diameter of 25 to 180 mm, wall thickness of 3.5-20 mm, sub-normal precision and high precision two . kinds of bearings for steel production and steel bearings are the following (expressed labeled 'roll' of G): chromium bearing steel as GCr6, GCr9 (SiMn), GCrl5 (SiMn); chromium-bearing steels such as GSiMnV (Re) , GSiMnMoV (Re), GMnMoV (Re); carburizing bearing steel such as G20CrMo, G20Cr2Mn2Mo;. high carbon chromium bearing stainless steels such as 9Cr18 (Mo) and other production bearing steel technical conditions more stringent, requirements of finished chemical composition, mechanical properties , process performance, grain size, carbide shape, decarburization depth and so comply with the relevant standards.
Gr15 bearing chemical composition of precision steel tubes
Annealed steel bar, wire annealing, or 830-840 degree oil quenching.
1. Ordinary annealed: 790-810 degree heat; furnace cooled to 650 degrees; air-cooled -HB170-2
2. Isothermal annealing: 790-810 degree heat; 710-720 degree temperature; air-cooled -HB207-229
3. Positive Fire: 900-920 degree heat, air cooling -HB270-390
4. tempering: 650-700 degree heat, air cooling -HB229-285
5. Quenching: 860 degree heat, oil quenching -HRC62-66
6. tempering: 150-170 degrees tempering, air cooling -HRC61-66
7. carbonitriding: 820-830 degrees permeation 1.5-3 hours, oil quenching, -60 degrees to -70 degrees to +150 degrees cryogenic treatment to +160 tempering, air cooling -HRC≈67
Quality bearing steel smelting demanding, and requires strict control of content and distribution of sulfur, phosphorus, and non-metallic inclusions, because the life of the bearing steel great influence on bearing steel basic quality content and distribution of non-metallic inclusions requirement is pure and homogeneous. pure and non-metallic impurity elements is less debris uniform organization is to fine carbide steel, to be evenly distributed. The higher the amount of inclusions, the more short-lived. In order to improve the quality of smelting, has recently electric furnace smelting and by ESR, you can use a vacuum smelting, vacuum consumable refining new technology to improve the quality bearing steel.
In addition to doing ball bearing rings endures, sometimes used to make tools, such as dies, measuring tools.
Good overall performance. After annealing the ball good cutting performance. High hardness after quenching and tempering and uniform, high wear resistance and contact fatigue strength Good thermal processing performance contains more alloying elements, the price is relatively cheap.