Application of the hottest metal self repairing ma

2022-08-02
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Application of metal self-healing materials in bearings

Abstract: metal wear self-healing materials are composed of a group of ultra-fine powders of natural mineral materials, which are added to lubricating grease (or oil). During bearing operation, chemical replacement reaction occurs under the action of heat energy generated by metal wear on the friction surface, and a smooth iron-based silicate wear-resistant protective layer (cermet layer) is generated on the friction surface of rolling elements and raceways, The service life of the bearing is greatly increased

key words: bearing wear self repair wear-resistant protective layer

since the reform and opening up, the development of China's bearing industry has made remarkable achievements. Since 2000, according to the annual output of bearings, China has become the fourth largest country in the world after Japan, the United States and Germany. The annual output of bearings has reached more than 2billion sets, and the annual output value is about 24billion yuan. Among them, the export volume accounts for more than 50% of the total output, and the annual foreign exchange earnings are about 700million US dollars. In recent years, China's bearing products have also made significant progress in dimensional accuracy, rotation accuracy, vibration and noise, life and reliability. However, there is still a big gap in variety and quality between domestic bearings and those of foreign countries. To further increase the variety and improve the quality, efforts must be made in the design, manufacturing, materials, testing, lubrication and other comprehensive technologies of bearings, which need a development process. The application of metal wear self-healing materials in domestic bearings improves the reliability of bearings, reduces the friction coefficient between bearing raceways and rolling elements, greatly prolongs the service life of bearings, and makes general bearings a big step forward in the direction required by the new concept of "infinite life", which has significant economic benefits

I. overview of the variety and quality of bearing products in China:

from 1997 to 1999, according to the "catalogue of national supervision and spot check products" formulated by the State Bureau of quality and technical supervision, the product quality of rolling bearings was spot checked, and the average qualification rate for three years was 68%. The product quality of the spot check in 2000 was 6% higher than that in 1999, which proved that the management of quality supervision and spot check had achieved remarkable results. Compared with developed countries in bearing industry, the gap in variety and quality of domestic bearings is mainly reflected in:

1. There are few varieties of domestic bearings and low output value. Developed countries in the bearing industry produce 150000 bearing varieties, while China produces only more than 20000 bearing varieties, most of which are general-purpose products. There are more than 2000 domestic bearing enterprises, and the total annual output value ranks behind the world's five major bearing companies (SKF, NSK, Koyo, NTN and NMB). Therefore, China's bearing enterprises are small in scale and low in output value. The average price of each set of exported bearings in China is only US $0.4

2. The dispersion of dimensional accuracy tolerance of domestic bearings is large. Although our bearings have made great progress in dimensional tolerance and rotation accuracy, close to the level of foreign famous brand products, there is still a big gap in the dispersion of dimensional deviation

3. In terms of vibration, noise and abnormal sound, the vibration extreme value level of bearings in China is more than 10dB higher than that of foreign famous brand products. Taking 6202 bearing as an example, the foreign famous brand products are about 26dB. The products of 18 domestic bearing enterprises are sampled, and the average value is 37.5db

4. The service life and reliability of domestic bearings are still low. Taking deep groove bearings as an example, the service life of foreign famous brand products is generally 8 times longer than the calculated service life (up to 30 times or more), and the reliability is more than 0.98; The service life of domestic bearings is generally 3~5 times of the calculated service life, and the reliability is about 0.96

due to the above-mentioned gaps in the variety and quality of domestic bearings, as a large bearing production country, China's growing industries such as home appliances, automobiles, textiles, machine tools and so on have to import a large number of bearings from abroad every year. The imported bearing products are mainly low-noise and silent ball bearings for household appliances, long-life automobile bearings, machine tool spindle bearings, high-speed railway passenger car and freight car bearings, high-speed textile machinery bearings, etc. 640million sets were imported in 1999, 930million sets in 2000 and 720million sets in 2001. See Table 1

statistical table of bearings imported from abroad (Table 1)

bearing category 1999 2000 2001 application field

quantity (10000 sets) value (10000 sets) quantity (10000 sets) value (10000 sets) value (10000 sets) value (10000 dollars)

ball bearing household appliances, machine tool spinning

provide different solutions conical roller bearing automobile

wheel radial impact testing machine detailed introduction

spherical roller bearing mine, petroleum machinery

needle roller bearing automobile Textile machinery

cylindrical roller bearing machine tools, rolling mills

other machines with very broad market prospects rolling bearing machine tools

textile machinery with pedestal bearings

total

due to the short service life of domestic bearings, the bearings can not have the same service life as electromechanical equipment. Stop the machine for maintenance and replace the bearings, which reduces the utilization rate of equipment and increases the maintenance cost. The failure caused by the low reliability of bearings has caused many major accidents. The new concept of "infinite service life" has been applied to the general bearings produced in developed countries of bearing industry. The special bearings also put forward the index requirements of "synchronous service life" with the supporting host and "zero failure" during the overhaul period. Therefore, domestic bearings must continue to work hard to improve product life and reliability

II. The "metal wear self-healing material" increases the installation of the axle (1) testing machine and the bearing life and reliability of the foundation:

"metal wear self-healing material" is a group of magnesium hydroxysilicate [mg6 (si4o10

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