KOYO bearings in order to improve the service life and reliability necessary to reduce the content of impurities in the bearing steel.

      First, a strict low magnification and microscopic (high power) organizational requirements

      Bearing Steel low magnification refers to the general loose, center porosity and flat analysis, microscopic (high power) organizations, including organizations of steel annealing, carbide mesh, ribbon and liquid analysis and so on. Carbide liquation hard and brittle, brittle inclusions with the same dangers. Carbide reduce the impact toughness, and to organize uneven quenching easily deformed and cracking. Carbide strip annealing and quenching and tempering influence organizations and contact fatigue strength. Low, high-powered organization on the merits of the quality of rolling bearings have a great impact, therefore, KOYO bearings manufacturing specification for low-, high-powered organizations have strict requirements.

      Second, the external and internal defects particularly stringent requirements

      KOYO bearings steels for external defects including cracks, slag, burrs, scarring, scale, etc., internal defects including shrinkage, bubbles, white spots, severe osteoporosis and segregation. For the processing of these defects bearings, KOYO bearings performance and life have a great impact, bearing data specification clearly states allowed these deficiencies.

      Third, the particularly stringent requirements carbide

      KOYO bearings in steel, carbide if severe uneven distribution in the heat treatment process can easily result in non-uniform microstructure and hardness of steel tissue heterogeneity on contact fatigue strength has a greater impact. In addition, severe carbide heterogeneity also easy to make when bearing parts in the quenching cracks, carbide heterogeneity can lead to a reduced life KOYO bearings Therefore, the bearing data specification for different specifications of steel are clearly The special requirements.

      Fourth, the particularly stringent requirements of appearance decarburization

      KOYO bearings data specification decarburization of the steel exterior has strict rules, if the appearance of decarburization provisions do not meet the standard range, and before the heat treatment during processing nor removed in its entirety, then the heat treatment quenching quenching process is prone to cracking, resulting in scrapped parts.

      Fifth, other requirements

      Bearing steel specification also bearing steel smelting method, oxygen content, annealing hardness, fracture, the remaining elements, sparks inspection, delivery status, logo, etc., there are strict requirements.