NTN Bearing Steel and direction of new technology-Wenzhou Bearing wholesale

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NTN Bearing Steel and direction of new technology

点击数：4727 日期：2014/4/4

NTN Bearing steel is mainly used in the manufacture rolling rolling elements and rings NTN bearings . Since NTN Bearing should have a long life , high precision, low heat , high speed, high rigidity, low noise , high wear resistance and other characteristics, thus requiring NTN Bearing Steel should have: high hardness, even hardness, high elastic limit , high contact fatigue strength , toughness must certainly hardenability in atmospheric corrosion resistance of lubricants . To achieve these performance requirements, the chemical composition of the steel bearing NTN uniformity , non-metallic inclusion content and type, size and distribution of the carbides , decarburization demanding. NTN Bearing Steel to develop high-quality, high performance and the overall direction of many varieties . NTN Bearing steel according to the characteristics and application environments are divided into : high carbon chromium bearing steel NTN , NTN Bearing carburizing steel, high temperature NTN Bearing steel , stainless steel and special NTN Bearing NTN Bearing specialty materials . To meet the high-temperature , high-speed , high-load , corrosion , anti-radiation requirements, the need to develop a series of new NTN Bearing steel with special properties . In order to reduce the oxygen content of the NTN bearing steel , the development of the vacuum smelting, remelting , electron beam remelting NTN Bearing steel smelting technology . The bulk of NTN Bearing steel smelting electric arc furnace melting, beginning to develop into all types of outside plus refining furnace . Currently , the use of a capacity greater than 60 tons beginning furnace + LF / VD or RH + casting + NTN Bearing steel rolling production process in order to achieve high-quality, high efficiency , low energy consumption purposes. In terms of the heat treatment process , the car bottom furnace, bell furnace developed into a continuous annealing furnace controlled atmosphere heat treatment . Currently, continuous heat treatment furnace up to 150m, processing and production of steel ball bearings NTN organizational stability and uniformity , decarburization small , low energy consumption . Since the 1970s , along with economic development and industrial technological progress, expand the scope of application of NTN Bearing ; while the development of international trade , and promote the development and application of international standards NTN Bearing steel and new technologies , new processes and new equipment , high efficiency, high quality, low cost technology and process equipment supporting emerged . Japan and Germany etc. and built a high- purity, high-quality NTN Bearing steel production line , so that the rapid increase in steel production , greatly improve the quality of steel and fatigue life . Japan and Sweden, the oxygen content of NTN Bearing steel production dropped to below 10ppm . The late 1980s, Japan 's Sanyo Special Steel advanced level of 5.4ppm, reached the level of vacuum remelting NTN Bearing Steel . NTN Bearing contact fatigue life of the uniformity of the steel structure is very sensitive . Improve the cleanliness ( decrease in steel content of impurity elements and inclusions ) , to promote non-metallic inclusions in steel and carbide fine and uniform distribution of NTN Bearing steel can improve the contact fatigue life . NTN Bearing steel using state of the organization should be uniformly distributed under the fine carbide particles on a tempered martensitic matrix , such an organization can give performance NTN Bearing steel needs. NTN Bearing carbon steel main alloying elements are carbon , chromium , silicon, manganese and vanadium . How to get NTN ball bearing steel production organization is an important issue , TMCP is an important advanced production technology NTN Bearing Steel . Through the controlled rolling or cold rolling quickly eliminate the carbide network , obtain the appropriate preparatory organization , you can shorten NTN Bearing Ball annealing time , thinning carbide , improve fatigue life. In recent years , Russia and Japan, using low-temperature controlled rolling (800 ℃ ~ 850 ℃ or less ) , plus a short time after rolling annealing using air cooling , or completely cancel the ball annealing process , you can get qualified NTN Bearing Steel . NTN Bearing Steel 650 ℃ temperature processing is also new technology . Before eutectoid steel or high carbon steel having a thermal processing if the fine grains or fine grains can be formed during processing , then ( 0.4 to 0.6 ) within the range of melting temperature , at a given strain rate , showing superplasticity . Naval Postgraduate School (NSP) for 52,100 steel processing temperature of 650 ℃ tests showed that at 650 ℃ 2.5 true strain fracture does not occur. Therefore, it is possible to 650 ℃ temperature processing instead of processed and combined with the high temperature annealing process the ball , which simplifies the equipment and processes , energy conservation , improve quality are important. In the heat treatment , annealing at improving the quality of the ball , get a small , uniform, spherical carbides and shortening the annealing time or cancel the ball annealing process research progress has been made , namely wire rod produced using two organizations annealing, drawing after 720 ℃ ~ 730 ℃ annealing recrystallization annealing to 760 ℃ tissue . So you can get a low hardness , ball , and no network carbide organization , the key is to ensure that the middle drawing reduction rate ≥ 14%. The process of heat treatment furnace efficiency increased by 25 % to 30 %. Continuous ball annealing heat treatment technology is the development direction of NTN Bearing steel heat treatment . Countries are in the research and development of new NTN bearing steel, and expand the application instead of the traditional NTN Bearing steel. NTN carburizing bearing steel such as fast , by changing the chemical composition to increase the rate of carburization , wherein the carbon content is increased from the conventional 0.08% to 0.20% to about 0.45% , the carburizing time from 7 hours to 30 minutes . NTN has developed a high-frequency hardening bearing steel , ordinary steel or carbon manganese, chromium steel , hardened by induction heating to replace the ordinary NTN Bearing steel , not only simplifies the production process and reduce costs, and increase service life. Japan developed GCr465, SCM465 fatigue life than SUJ-2 2 ~ 4 times higher . Due to the use of NTN Bearing in harsh high temperature , corrosion, lubrication environment more and more used in the past M50 (CrMo4V), 440C (9Cr18Mo) and other NTN Bearing steel can not meet the requirements , the urgent need to develop good processing performance, low cost , long fatigue life, can be suitable for different purposes and uses of NTN bearing steel, such as high temperature carburizing steel M50NiL, easy processing stainless steel 50X18M NTN bearing NTN bearings and ceramic materials. For GCr15SiMn low hardenability steel weaknesses , China has developed a high hardenability and hardenability NTN Bearing steel GCr15SiMo, its hardenability HRC ≥ 60, hardenability J60 ≥ 25mm. GCr15SiMo contact fatigue life L10 and L50 , respectively, 73% and 68% increase compared GCr15Si Mn, under the same conditions , NTN bearing life is made of steel with a double G015SiMo GCr15SiMo steel. In recent years, China has developed can save energy, save resources and impact of GCr4NTN bearing steel. Compared with GCr15, GCr4 shock value increased by 66% and 104% , fracture toughness increased by 67% , contact fatigue life L10 increased by 12 %. NTN Bearing GCr4 steel with high temperature heating - surface hardening heat treatment process. And full of GCr15 steel hardenability compared NTN Bearing , GCr4 steel NTN Bearing life is significantly improved, can be used for heavy-duty high-speed trains NTN bearings. NTN Bearing steel major development in the future in both directions diversified high cleanliness and performance . NTN Bearing steel to improve cleanliness , especially to reduce the oxygen content in steel , can significantly prolong the life of NTN Bearing . The oxygen content is reduced to 28ppm 5ppm, one can extend the fatigue life of magnitude . In order to extend the life of NTN Bearing Steel , people over the years has been committed to the development and application of refined techniques to reduce the oxygen content in steel . Through unremitting efforts , NTN Bearing Steel lowest oxygen content from the 1960s to the 1990s reduced 28ppm 5ppm. At present, China can NTN Bearing Steel lowest oxygen content is controlled at about 10ppm. Changes in environmental requirements NTN bearings NTN Bearing steel must have diverse properties. If the device speed increases, the need for high temperatures prospective (200 ℃ or less ) NTN Bearing steel ( commonly used to improve the content of Si on the basis of SUJ2 steel , adding Nb, V and methods to achieve the purpose of anti- softening and stable size ) ; corrosive applications occasions , the need to develop NTN bearing stainless steel ; to simplify the process , should develop high-frequency hardening NTN bearing NTN bearing steel and short carburizing steel ; in order to meet the needs of the aerospace , high temperature should be developed NTN bearing steel.

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