NTN bearing steel is mainly used in the manufacture of rolling NTN bearing roller and ring.
Because the NTN bearing should have long life, high precision, low calorific value, recommend suite, high rigidity, low noise, high abrasion resistance and other characteristics, therefore requires NTN bearing steel should have: high hardness, uniform hardness, high elastic limit, high contact fatigue strength, must toughness, hardenability, in atmospheric corrosion resistance of lubricant.
In order to achieve the above performance requirements, uniformity of the chemical composition of NTN bearing steel, non-metallic inclusion content and type, strict carbide particle size and distribution, decarburization, etc.
NTN bearing steel in general to develop in the direction of high quality, high performance and many varieties.
NTN bearing steel according to the characteristic and application environment are divided into: NTN high carbon chromium bearing steel, carburized NTN bearing, high temperature NTN bearing steel, stainless steel special NTN bearing NTN bearing steel and special materials.
In order to adapt to high temperature, high speed, high load, corrosion resistance, resistance to radiation, need to develop a series of new type of NTN bearing steel with special performance.
To decrease the oxygen content of NTN bearing steel, the development of the vacuum smelting, esr, electron-beam remelting of NTN bearing steel smelting technology.
And the mass of NTN bearing steel smelting electric arc furnace smelting, early developed into all kinds of smelting and refining outside the furnace.
At present, the use of early capacity greater than 60 tons + LF/VD and RH refining furnace, continuous casting and rolling process NTN bearing steel production, in order to achieve the purpose of high quality, high efficiency, low energy consumption.
In terms of heat treatment process, from the car type furnace, bell type furnace developed into the continuous controlled atmosphere heat treatment of annealing furnace.
At present, the longest continuous type heat treatment furnace is 150 m, processing production of NTN bearing steel spheroidizing stable and uniform, the decarburization layer is small, low energy consumption.
Since the 1970 s, when economic development and industrial technology progress, to expand the application scope of NTN bearing;
And the development of international trade, and promoted the NTN bearing steel standard internationalization and the development of new technology, new technology and new equipment and application of high efficiency, high quality and low cost of supporting technology and process equipment arises at the historic moment.
Japan and Germany are built high cleanliness, high quality of NTN bearing steel production line, make the output of steel increased rapidly, the quality of the steel and greatly improve the fatigue life.
Japan and Sweden, the production of the oxygen content of NTN bearing steel to 10 parts per million.
In the late 80 s, the advanced level of Japanese sanyo special steel company is a 5.
4 PPM, achieved the level of vacuum re-melting NTN bearing steel.
NTN bearing 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 NTN bearing steel.
NTN bearing steel using state organization should be tempered martensite matrix uniformly distributed on the fine carbide particles, such organizations can give the NTN bearing steel required performance.
The main alloy elements in the high carbon NTN bearing steel with carbon, chromium, silicon, manganese, vanadium, etc.
How to get the ball organization
