New technology and the future development of the bearing steel Chuangyu forecast
updated: 2012-11-22 0:00:00 hit:2816
Bearing steel is mainly used for manufacturing move the body to move bearing and rings. Because the bearings should have a long life, high precision, low fever, high-speed, high rigidity, low noise, high abrasion resistance and other properties, thus requiring bearing steel should have: high hardness, the average hardness, high elastic limit, high contact fatigue strength, toughness necessary, a certain degree of hardenability, in the atmosphere of the lubricant in the erosion resistance function. In order to achieve the above-described functional requirements, the average chemical composition, the content and type of non-metallic inclusions, a carbide particle size and distribution, decarburization and other requirements of the bearing steel stringent. Bearing steel in general, to the development of high-quality, high-performance and direction of many varieties. The bearing steel according to the characteristics and application environments divided as follows: carbon chromium bearing steel, carburizing bearing steel, high temperature bearing steel, stainless bearing steel and dedicated special bearing materials.
In order to meet the high-temperature, high-speed, high-load, corrosion resistance, anti-radiation requirements, the need to develop a series of new bearing steel with a special function. In order to reduce the oxygen content of the bearing steel, developed a the vacuum smelting and remelting, electron beam remelting bearing steel smelting technology. The bulk bearing steel smelting electric arc furnace melting develop into various types of early furnace plus furnace refining. Currently, with a capacity greater than 60 tons of early furnace + LF / VD or RH + casting + rolling process produced bearing steel, in order to achieve high-quality, high efficiency, low energy consumption purpose. In the heat treatment process, car bottom furnace, bell furnace developed into a the continuous controlled atmosphere annealing furnace heat treatment. At present, continuous heat treatment furnace up to 150m, processing produced bearing steel ball of the organization into chaos and average, decarburisation, low energy consumption.
Since the 1970s, followed by economic development and industrial technology improves, the scope of application of the bearing to expand; international business development, and to promote the internationalization and new technologies of the bearing steel scale, the development and application of new technology and new equipment, high efficiency high quality, low cost supporting technology and process equipment came into being. Japan and Germany are built high cleanliness, high-quality bearing steel production line, steel production is increasing rapidly, the quality of steel and the fatigue life of generosity progress. Bearing steel produced in Japan and Sweden content is reduced to below 10ppm. The late 1980s, Japan's Sanyo Special Steel Company improve predecessors level of 5.4ppm, reach a the vacuum remelting bearing steel level.
Contact fatigue life of the bearings are very sensitive to the average of Steel. Progress cleanliness (to reduce the content of the impurity element in the steel and inclusions), prompting the nonmetallic inclusions in the steel and carbide fine average distribution, can progress contact fatigue life of the bearing steel. Organization in the state of use of the bearing steel should be evenly distributed in the matrix of tempered martensite with a fine carbide particles, such an organization can be given to the function required by the bearing steel. Carbon bearing steel of the main alloying elements such as carbon, chromium, silicon, manganese, vanadium. (Chong Yu imports bearing company specializes in SKF bearings, NSK Bearings, FAG bearings, INA bearings, NTN By Order, TIMKEN bearings and other well-known brands imported bearings! Provide SKF bearings imported bearings, INA bearings and other bearings Model inquiries, please call talk! telephone 020 -36323918.)
How do I get the ball of the organization are important topics in bearing steel produced, controlled rolling and cooling process is important to improve predecessors bearing steel produced. Controlled rolling or after rolling fast-cooling eliminates network carbide suitable preparation organization, can shorten bearing balls annealing time, the refinement of carbide, progressive fatigue life. Bearing transaction network expert survey, in recent years, Russia and Japan, using low-temperature controlled rolling (800 ℃ ~ 850 ℃), air cooling plus short time annealing after rolling, or completely cancel spheroidizing, you can get qualified bearings Steel. Bearing steel 650 ° C temperature processing also a new type of technology. Before thermal processing eutectoid steel or high carbon steel having a fine grain structure, or in the process can form a fine grain, within the melting temperature range of (0.4 to 0.6), in a certain strain rate, exhibit superplasticity. Naval Postgraduate School (NSP) 52100 steel 650 ° C temperature processing test showed that the true strain of 2.5 is not broken at 650 ℃. Therefore, it is possible to 650 ° C temperature processing instead of high-temperature processing, combined with spheroidizing, which simplifies the equipment and processes, energy conservation, progress, quality is important.
The heat treatment, in progress in the quality of ball annealing, to obtain small, on average, the spherical carbide as well as shorten the annealing time or cancel the ball annealing process research progress has been made on that wire rod produced using the two organizations annealing, the drawing recrystallization annealing after the 720 ° C ~~ 730 ° C and changed to 760 ° organization annealing. This can be obtained a low hardness, good spheroidization mesh carbide tissue, the hub to ensure that the the intermediate pullout reduction rate ≥ 14% of the process of the heat treatment furnace efficiency to progress from 25% to 30%. Continuous ball annealing heat treatment technology is the development direction of the bearing steel heat treatment.
All countries in the research and development of new bearing steel, and expand the application instead of the conventional bearing steel. Such as rapid carburizing bearing steel, by changing the chemical composition progress carburizing speed, wherein the carbon content in progress by the conventional 0.08% to 0.20% to about 0.45%, the carburizing time shortened from 7 hours to 30 minutes. The development of high-frequency hardening bearing steel, ordinary in carbon steel or in carbon manganese, chromium steel, instead of plain bearing steel by high-frequency heating quenching, simplify produced in the process and reduce the cost, and progress in the life. Developed in Japan GCr465, SCM465 fatigue life of 2 to 4 times higher than SUJ-2. Because in the harsh environment of high temperature, erosion, lubrication premise bearing more and more the the past use the M50 (CrMo4V) bearing steel as of 440C (9Cr18Mo) can not be satisfied the requirements, the urgent need to develop processing function, low cost and tired long life, bearing steel suitable for different purposes and uses, such as high temperature carburization steel M50NiL, easy to processing stainless of bearing steel 50X18M well ceramic bearing material.
For GCr15SiMn steel hardenability low weaknesses, our development of high hardenability and hardened bearing steel GCr15SiMo hardenability HRC ≥ 60 hardenability J60 ≥ 25mm. GCr15SiMo contact fatigue life L10 and L50, respectively, 73% and 68% than GCr15SiMn progress, manufacturing G015SiMo steel bearing life is GCr15SiMo steel twice in the same use of the premise. In recent years, China has also developed the energy conservation, resource conservation and impact GCr4 bearing steel. Impact value with GCr15 unmatched, GCr4 progressed from 66% to 104%, 67% improvement in fracture toughness, and contact fatigue life L10 progressed by 12%. GCr4 steel bearings are made of high-temperature heating - Surface Heat Treatment. The through hardened GCr15 steel bearing analogy life of GCr4 steel bearing significant progress for heavy-duty high-speed train bearing.
Bearing steel mainly to the high degree of cleanliness and functional diversification future development in both directions. Progress bearing the cleanliness of steel, in particular reducing the amount of oxygen in the steel, can significantly extend the life of the bearing. The oxygen content is reduced to 5 ppm by 28ppm fatigue life can be extended to a number of levels. In order to extend the life of the bearing, the people over the years has been committed to the development and application of refined techniques to reduce the oxygen content in the steel. Through unremitting efforts, the minimum oxygen content in bearing steel from the 1960s 28ppm reduced to 5ppm 1990s. At present, China can be a minimum oxygen content control in bearing steel about 10ppm. Bearing steel bearing use changes in the environment requirements necessary to have the functional diversification. Such as the the equipment speed of progress, needs quasi-bearing steel for high temperatures (200 ° C or less) SUJ2 steel based on the progress of the Si content, add V and Nb (usually used to achieve the purpose of anti-softening and chaos size); erosion applications occasions, need to be developed bearing stainless steel; frequency quenching bearing steel and short term carburizing bearing steel, should be developed in order to simplify the process; should be developed content with the needs of the aerospace, high temperature bearing steel.