The bearings are almost everywhere in our lives, bikes shared on the side of the road, household appliances at home, in the spacecraft in the sky, the aircraft carriers launched and all this cannot exist without postponement.
However, the main bearings used in high precision machines are still in a technical difference in my country.
The precision of the roller bearings is generally divided into five levels: P0, P6, P5, P4 and P2.
For high-tech fields such as CNC machine tools and machining centers, super-precision and superior bearings must be selected. Everything above depends on imports.
Video: Experts analyze the problem of the deposit between home and abroad
The main reasons for the big mass gap between interior bearings and imported bearings are:
01
Difference in quality of bearings
A large number of domestic and foreign experiences have shown that the quality of treatment of cages, ferrules and steel balls has different degrees of impact on rolling vibrations. The quality of treatment of ferrules, and the main impact are factors are roundness, corruption, surface roughness, damage caused by the surface bump, etc. Ball and steel ferrule.
The most important problem of steel ball products in my country is that the vibration values are important and the surface defects are serious (unique points, group points, pits, etc.). are not inferior to the outside of the circle, the sleeve is closed. , which also shows that the machine tool has poor resistance to vibrations, and there are problems with the grinding wheel, the grinding disc, the coolant and the process parameters. , scratches and burn.
For ferrules, the most serious impact on rolling vibrations is the ripple of the canal and surface roughness. For example, when the interior and exterior channels of the deep and average groove ball bearings are greater than 2 μm, it will have a significant impact on the vibration of the bearing. The vibration value increases with the increase in undulation and the channel is seriously damaged.
02
Keep a distance between production processes, talents, etc.
1. The gap in industrial technology.
The social status of rolling technicians and even engineers is not respected as they deserve (this situation has improved a lot in recent years). The education industry of my country is unbalanced and technical education has not received the attention it deserves, which led young people who prefer to be white -collar workers only to work on the front line of production . At the same time, it also led to starting a business in China.
2. The deviation of equipment.
The World Steel looks at China, and China Steel looks at Hebei, but that only refers to the production of raw steel, which is also one of the reasons why the world economy has decreased in recent years, the Internal production capacity of steel was overcapacity and steel prices have been slow. Alloy Steel has always been a gap in the national steel industry, and high -end metallurgy technology is strictly held by developed countries. .
3. The gap in production technology.
Here I will only talk about my own thoughts. Production technology is the most important link in industrial technology, and it is a cyclical change process, quantitative change produces a qualitative change. Taking the example of machine tools, the bearings have a huge impact on the precision of machine tools. The lifespan and precision of interior precision bearings are extremely different from those of foreign bearings.
4. Deposit of production equipment.
Roll manufacturers and application manufacturers are the relationship between fish and water. Without good bearings, good equipment cannot be produced and high quality bearings cannot be produced without reliable machine tools. As far as I know, large-scale machine tools are purchased by large-scale machine tools. Some manufacturers of domestic domestic bearings prefer to buy old-fashioned machine tools of the last century and transform them into special machine tools for the treatment of bearings to buy machine tools from well-known domestic brands. There are price factors and practical factors.
5. No powerful supporters.
In recent years, my country’s high -speed rail technology has grown rapidly, but high -speed rail bearings have been bought from the Schaeffler group, Germany. The fundamental reason is that, under the control of certain leaders, Schaeffler, the North West factory, began to cooperate. However, during the cooperation process for several years, the Northwest Bearing Factory has not received the technical support it deserves and also lost a large market share, leading to the decline of the northwest of the rolling today .
03
Whites for high -end bearings applications
Compared to foreign countries, interior bearings have a large gap in high -end and important bearings, and the main industries are:
1. aviation
As a basic key component of aircraft engines, foreign countries are developing second-generation plane motor bearings with a 15-20 thrust ratio and are preparing to be assembled in fifth generation hunting aircraft 2020. In the past 10 years, the United States has developed the second generation of rolling steel for aviation engines. ), China the development of bearings for second generation plane engines is underway.
2. Automobile
For automotive centers bearings, China is currently using first and second generation center bearings (ball bearings), while Europe has largely used third generation HUB bearings. The main advantages of the third generation center bearing are reliability, short payload spacing, easy installation, no required adjustment, compact structure, etc. Currently, most models introduced in China use this light and integrated structural concentrator bearing.
3. Railway vehicles
Currently, the train bearings in heavy service in China are made of glued steel by domestic electrolar re -tapering G20CRNI2MOA, while foreign countries have fusion technology at the suction and a technology of homogenization of inclusion ( IQ Steel) in Ultra-High Pureness Steel (EP Steel) were used to produce vacuum cleaner fusion technology and inclusion homogenization technology (IQ steel) of ultra-high purity rolling steel (Steel EP), ultra-long life life technology (TF steel), a fine quality heat treatment technology, super hard-working treatment technology and advanced waterproofing and lubrication technologies are applied to the Production and manufacture of bearings, thus considerably improving the life and reliability of the bearings. China’s electric slag steel has not only low quality, but also costs 2,000 to 3,000 yuan / tonne more than vacuum degassing. Ringing steel to replace ride steel from electric electrics used.
4. Wind energy
For wind bearings, China is currently unable to produce spit and speed bearings with high technical content, and is essentially based on imports. In order to improve the resistance, tenacity and lifespan of wind bearings, a new SHX special heat treatment (40crsimo) has been adopted abroad. .
Carbon-bezote co-pairing is used for speed increase rolling and spindle bearing, so that the surface of the parts can obtain a more stable austenite residual volume fraction (30% -35% ) and a large number of fine carbids and carbon nitrures, (30% to 35%) and a large number of fine carbids and carbon nitrures, improvement of the lubrication of pollution of the lifespan of bearings in working conditions.
04
Department of future improvement in domestic bearings
It is mainly reflected in four aspects of improvement:
1. Steel cleanliness
Under the premise of the examination of the economy, the cleanliness of the steel will be further improved, the oxygen and titanium content in steel will be reduced and the mass fractions of oxygen and titanium in the Ringing steel will be less than 6 × 10-6 and 15 × 10-6 respectively.
2. Refinement and organizational balance
Thanks to the application of alloy design and the application of controlled rolling and cooling technology, the uniformity of inclusions and carbides will be further improved, and mesh and band carbides will be reduced and eliminated , the average size and maximum size of the particles will be reduced, so that the average size of the carbides will be smaller than that of the carbides.
3. Reduce low and more fabric defects
Reduce central relaxation, central withdrawal and segregation of central composition in rolling steel and improve the uniformity of the fabric of weakness and more.
4. Tenacity of rolling steel
Thanks to the optimization of new alloy and hot bearing processes and research on the heat treatment processes, the tenacity of rolling steel is improved.
Although domestic bearings have many differences with imported bearings, after the continuous development of Chinese, more high quality bearings will be developed and many excellent bearings are born.
In December 2013, the “Jade Rabbit” successfully landed on the Moon. Although we feel and excité, we cannot forget the scientific researchers and the companies which are silently devoted to the development of national science and technology. Do not rely on imported bearings, which is of great importance.
This means that the gap between national bearings and imported bearings becomes more and smaller, and that interior technology is closer to high international standards, and is even in a leading position in certain technologies. For some ordinary machines, the level of bearings may not be high, but the requirement of the “jade rabbit” to jump on the moon is very high. Flexibly.
Although the interior bearings have only developed for decades and are not very advantageous in relation to the hundreds of years of foreign history, we can only summarize it so shortly to catch it, it That is to say that the Yangtze river pushes the previous waves.
Speaking of this, I will share a
Video of a German turning five bearings in one room for 9 minutes
Very shocked after watching
Share with you here
The iron bearing is a popular game recently. The bearings are the comparison depends on the four key points.
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