NSK bearing steel and direction of new technology

NSK bearings of contact fatigue life is sensitive to the uniformity of steel group. Improve cleanliness, Reduce the impurity elements in the steel and inclusion content) , prompting the non-metallic inclusions in steel and carbide tiny uniform distribution, can improve the contact fatigue life of NSK bearing steel. Bearing steel using state organization should be tempered martensite matrix uniformly distributed on the fine carbide particles, such organizations can give the performance of the bearing steel needed. High carbon steel bearing the main alloy elements carbon, chromium, silicon, manganese, vanadium, etc. NSK bearings because should have long life, high precision, low calorific value, recommend suite, high rigidity, low noise, high abrasion resistance and other characteristics, therefore requires bearing steel should have: high hardness, uniform hardness, high elastic limit, high contact fatigue strength, must toughness, hardenability and the atmospheric corrosion resistance of lubricant. In order to meet the performance requirements, the chemical composition of NSK bearing steel uniformity, non-metallic inclusion content and type, strict carbide particle size and distribution, decarburization, etc. In order to adapt to high temperature, high speed, high load, corrosion resistance, resistance to radiation, need to develop a series of new NSK bearing steel with special performance. In order to reduce the oxygen content of NSK bearing steel, developed vacuum smelting, esr, electron-beam remelting of NSK bearing steel smelting technology. And the mass of NSK bearing steel smelting electric arc furnace smelting, early developed into all kinds of smelting and refining outside the furnace. On the side of heat treatment, improve the quality of spheroidizing annealing, small, uniform, spherical carbides, and shorten the annealing time or cancel the spheroidizing annealing process have the progress of research, namely the wire rod production by two organizations annealing, after drawing of 720 ℃ ~ 730 ℃ to 760 ℃ of recrystallization annealing annealing. So I can get a good low hardness, spheroidizing, no carbide network organization, the key to ensure the middle drawing degressive rate of 14% or higher. The process to improve the efficiency of the heat treatment furnace by 25% ~ 30%. Continuous NSK bearing steel spheroidizing annealing heat treatment technology is the development direction of heat treatment. NSK bearing steel is mainly in the future to develop in the direction of diversification and performance with high degree of cleanliness, two. Improve the cleanliness of bearing steel, reduce the oxygen content in the steel, in particular, can obviously prolong the life of NSK bearings. Oxygen content by 28 PPM down to 5 PPM, the fatigue life could be extended by one order of magnitude. In order to prolong the service life of bearing steel, people over the years has been committed to the development and application to reduce the oxygen content in the steel refining technology.