Gcr15 sale of imported high-quality bearing steel bearing steel plate production and sale of bearing steel main executive GB/T18254-2002 standards and adapted to user requirements forging bearing Laiwu GCr15JD Quality Agreement, which GCr15JD agreement strict quality requirements in GB/T18254-2002 standards, GCr15JD requires oxygen content ≤ 10ppm, center segregation levels ≤ 1.0 grade, composition control, length and size etc stricter than GB/T18254-2002 standard deviation. ① strict chemical requirements. General Bearing steel is mainly carbon chromium bearing steel, which is about 1% carbon content, adding about 1.5 percent chromium, and contains a small amount of eutectoid steel manganese, silicon elements. Chromium can be heat treated to improve performance, increase hardenability, organizational uniformity, tempering stability, but also can improve the performance of rust resistance and grinding steel. But when the chromium content of more than 1.65% increase of retained austenite after quenching, lower hardness and dimensional stability, increase the carbide heterogeneity, reducing the steel toughness and fatigue strength. To this end, high-carbon chromium bearing steels containing chromium content in the general control of 1,65% or less. Only by strictly controlling the chemical composition of the steel bearing, bearing performance can be met by a heat treatment step of microstructure and hardness. ② high dimensional accuracy requirements, for use in high-speed upsetting forging annealed bar, there should be a higher demand for its dimensional accuracy. Rolling steel steel require a higher dimensional accuracy, it is because most of the parts go through the bearing pressure forming. In order to save material and improve labor productivity, most bearing rings is through forging, cold heading or after the ball is hot-rolled forming, roller small size also after cold heading. If the dimensional accuracy of the steel is not high, you can not accurately calculate cutting the size and weight, but can not guarantee the quality of products bearing parts, are likely to cause damage to equipment and tooling. ③ particularly stringent purity requirements. The purity of the steel is the number of non-metallic inclusions contained in the steel, the higher the purity, the less the non-metallic inclusions in steel. Bearing steel oxide and silicate inclusions are harmful bearing lead to early fatigue spalling mainly significantly reduced bearing life. Especially damaging brittle inclusions, as easy to come off from the metal substrate in the process, seriously affecting the quality of the bearing surface after finishing parts. Therefore, in order to improve the life and reliability of the bearings must reduce the amount of inclusions in bearing steel. ④ strict low magnification and microscopy (high power) organizational requirements. Bearing Steel low magnification refers to the general loose, loose and flat center analysis, microscopy (high power) organizations, including organizations annealed steel, carbide mesh, ribbon and liquid analysis and so on. Carbide liquation hard and brittle, it's the same dangers and brittle inclusions. Carbide network to reduce the impact toughness, uneven and make organization easier when quenching deformation and cracking. Ribbon carbide annealing and quenching and tempering influence organizations and contact fatigue strength. Low, the merits of high-powered organization has a great impact on the performance and service life of rolling bearings, so the low standard bearing materials, high-powered organization has strict requirements. ⑤ particularly stringent requirements of surface defects and internal defects. Bearing steel, the surface defects including cracks, slag, burrs, scarring, oxide and other internal defects, including shrinkage, bubbles, white spots, severe osteoporosis and segregation. For the processing of these defects bearings, bearing performance and life have a great impact in the bearing material standard clearly states do not allow the emergence of these defects. ⑥ carbide of strict requirements. Bearing steel, carbide, if severe uneven distribution in the heat treatment process can easily result in non-uniform microstructure and hardness of steel tissue inhomogeneities have a greater impact on the contact fatigue strength. In addition, severe carbide heterogeneity also easy to make cracks in the bearing parts quenching, carbide heterogeneity will result in reduced bearing life and therefore, the standard bearing materials of different specifications of steel have a clear special requirements. ⑦ strict surface decarburization depth requirements. In the standard bearing material layer on the steel surface decarbonization has strict rules, if the surface decarburization beyond the prescribed range of the standard, and in front of the heat treatment process nor removed in its entirety, then in the process of heat treatment and quenching prone to quench cracking, causing parts of scrapped. ⑧ other requirements. Also bearing steel smelting method, oxygen content, annealed hardness, fracture, residual elements, sparks test standard bearing steel, delivery status, identity, etc. There are strict requirements. Physical properties of the physical properties of bearing steel microstructure mainly to check, decarburization, non-metallic inclusions, low magnification based. Under normal circumstances are annealed, annealed cold-drawn delivery. Delivery status should be specified in the contract. Steel low magnification must be no shrinkage, subcutaneous bubbles, white point and microscopic pores. Center porosity, generally should not loose more than 1.5, the segregation shall not more than two. Annealed steel organization should be fine granular pearlite evenly distributed. Decarburization depth, non-metallic inclusions and carbide of shall comply with the relevant national standards. Also known as high carbon chromium bearing steel steel, carbon content ωc is about 1% chromium content ωcr 0.5% -1.65%.