I. Current status of the bearing industry and overview of heat treatment technology and equipment
1. China's bearing industry continues to develop rapidly and stably
The construction and development of China's bearing industry over the past 50 years since the founding of the People's Republic of China, especially since the reform, opening up, sustained, rapid and stable development, has formed a larger industrial scale. In 2007, the whole industry produced 9 billion sets of various types of bearings and realized sales income of 76 billion yuan. Bearing production and sales revenue ranks third in the world.
China's bearing import and export trade volume has increased year by year. In 2007, the export of bearings earned 2.1 billion U.S. dollars, and the import use of foreign exchange was 2.1 billion U.S. dollars.
Since the "Ninth Five-Year Plan", the economic component of China's bearing industry has undergone profound changes. By 2006, according to sales, the state-owned: private: three capital = 16:63:21 pattern has been formed.
China's bearing industry has gradually improved its technical level and has certain technical strength. There is one (Luo Axis), one hospital (the tenth institute of Zhongji), and one school (Henan University of Science and Technology) as the backing. There are 5 national-level enterprise technology centers (万万, 瓦轴, 哈 axis, Luo axis, northwest) and 5 post-doctoral research stations (Wanxiang, Longxi, Luoxuan, Northwest, Hangzhou) and the whole country. 6 level laboratories (Luo Axis, Hangzhou Center, Shanghai Office, Wanxiang, Longxi, Wazhou). The product development capability of the whole industry has been greatly improved, and the bearing specifications of the bearings have increased from 39,000 in 1999 to more than 6,6000 in 2005. The matching rate for major equipment and key hosts is about 80%. There are major breakthroughs in high-end product development. The aerospace bearings and other defense equipment supporting bearings represented by the "God Five", "Shenzhou VI" and "Chang'e No.1" supporting bearings have all been based in China and have completely independent intellectual property rights. The long-term constraints on the vibration noise and sealing performance of micro-miniature deep groove ball bearings for domestic mainframes and expansion of exports have achieved remarkable results through the industry-wide technical research organized by China Axis Association, which can basically meet the domestic host supporting and expanding exports. The requirements of some companies' products have reached or are close to the level of international similar products.
2. China's bearing heat treatment technology and equipment made great progress
During the economic construction period of the "Sixth Five-Year Plan", "Seventh Five-Year Plan" and "Eighth Five-Year Plan", more than 20 bearing manufacturers have introduced equipment from industrialized countries such as Japan, the United Kingdom, the United States, Switzerland, West Germany, Austria, and Italy. Digestion and absorption, the main types of equipment have basically achieved localization at the end of the “Eighth Five-Year Planâ€, which has effectively promoted the technological progress of China's bearing heat treatment equipment and the manufacturing level of the electric furnace industry.
Pusher type isothermal spheroidizing annealing furnace is widely used in the bearing industry. Currently, this type of equipment is the main equipment for annealing bearing parts. Annealing of the protective atmosphere of bearing parts has begun to attract attention and has begun to be widely used in production.
The quenching and tempering equipment for bearing parts mainly includes mesh belt furnace, casting chain, roller hearth furnace, multi-purpose furnace, rotary hearth furnace and drum furnace production line. These production lines are the main equipment of heat treatment equipment in China's bearing industry, and also represent the level of bearing heat treatment equipment in China. The popularization and application of these equipments has greatly improved the quality of heat treatment of bearing parts in China. After quenching, the oxidized decarburization layer of the workpiece is reduced from 0.06 to 0.1 mm to 0.03 mm, and the batch hardness difference is reduced from the original 2HRC to less than 1.5HRC. The difference in hardness of the same piece is reduced from the original 1.5HRC to less than 1HRC, and the compression grinding retention is 1/3~1/2, which improves the grinding efficiency by 15%~22%, which contributes to the improvement of the overall quality of our bearing quality.
Carburizing heat treatment equipment mainly has pusher type, roller bottom type, mesh belt type gas carburizing automatic production line, also has multi-purpose furnace, vacuum carburizing furnace, well type furnace, periodic carburizing furnace, carbon potential control of carburizing atmosphere mostly With automatic control systems, flow control is also used.
3. Development direction of bearing heat treatment technology and equipment in China
(1) Medium and small-sized bearing rings High-volume production heat treatment equipment adopts Mafto roller type controllable atmosphere mesh belt furnace production line and controllable atmosphere casting chain furnace production line, replacing conveyor belt furnace, vibrating bottom furnace, box furnace and other backward furnace type .
(2) Large-scale and large-sized bearing rings High-volume production heat treatment equipment adopts controlled atmosphere roller hearth furnace production line and multi-purpose furnace production line.
(3) The heat treatment equipment for extra large bearing rings adopts a controlled atmosphere periodic heat treatment furnace or a pit furnace with a microcomputer carbon potential control device.
(4) Development of a controllable atmosphere with a nitrate salt martensite quenching small roller furnace and a roller hearth furnace production line.
(5) Promote the application of continuous controlled atmosphere carburizing production lines.
(6) Develop an automatic production line for high-frequency quenching and tempering of automobile wheel bearings.
(7) Rolling mill mass production heat treatment equipment adopts the drum furnace production line to replace the imitation Su drum type furnace production line.
(8) Development of a roller-type nitrogen-based protective atmosphere isothermal spheroidizing annealing furnace.
(9) Development and application of bainite austempering process equipment.
(10) Develop and develop automatic die-hardening machine tools for controllable atmosphere roller hearth furnaces and rotary hearth furnaces.
(11) Increase the proportion of vacuum heat treatment equipment.
(12) Develop and develop a quantity-variable sorting machine matched with the mesh belt furnace and the casting chain furnace production line.
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