Chinese patent (ZL99248914.8) non-stressed bolt combination self-solidifying ball mill liner General technical specification one

     Analysis of early failure causes of high manganese steel liner ZGMn13

Kilometer Anti-wear Engineering Research Institute (Xuzhou 221008)

Summary 1,

Careful analysis and understanding of the reasons for the elimination of high-manganese steel liners by the market is the basis for research and development of new products. Only by clearly recognizing the bottlenecks in the development of existing products can new ideas be developed in new products and processes. Taking a new structure, it is necessary to carefully analyze the surface and physical causes of the original liner before studying the new type of structural liner and process.

Abstract 2

The consumption of ZGMn13 ball mill liners in various industries in China is well known, not only because of the large number of mills used in this product, but also because of the unique mechanical properties of high manganese steel and the history of invention in the past 100 years. The wear-resistant materials are relished by peers.

The wear method of the traditional liner is usually divided into chisel wear, impact wear, sliding wear and spalling wear. The effective way to find the high manganese steel liner is to form the drum lining plate reverse arch deformation, deformation, shear cylinder bolt And cause failure deformation,

In particular, bulging and twisting are the most obvious failure phenomena. According to the author's statistics, more than 30 power generations are available in Yantai Power Plant, Huangdao Power Plant, Jinan Iron and Steel Plant, Xuzhou Power Plant, and Beijing Guohua Power Plant in Jiangsu Province and Shandong Province. The use of the liner of the plant, the grinding machine including DTM350/600, DTM250/390, DTM287/470, DTM380/700, the wear and tear situation accounted for 27% of the failure of the statistical mill.

At the same time, it was also found that the tightening of the partial lining and the end plate bolts were gradually broken when the mill was running for about one year.

The investigation also found that the hardness of the steel ball used in conjunction with the lining plate has different degrees of influence on the practical performance of the lining plate.

Abstract 3,

Analysis of Causes of Friction Medium Caused by Failure of High Manganese Steel

3, 1 high manganese steel before the use of the state of the austenite, its low yield strength and high elongation. According to the regulations of the Ministry of Metallurgical Industry, it is 300Mpa at room temperature, and &5 is not less than 20%. According to some domestic academic articles, &s is lower in the temperature environment above 200C Celsius, and &5 is rising, the pipe of the ball mill The hot air temperature is above 280C, and the temperature after mixing of the wind coal is also about 200C, so a small effect can cause large plastic deformation of the liner.

3, 2 In the metal materials science, the higher the hardness of the metal material, the greater the strength value and the elastic modulus, the stronger the rigidity, and the smaller the deformation pure force, when the ball is between the ball and the high toughness liner. When impact, rolling, and sliding occur, most of the energy is transferred to the lining, which causes the lining to be deformed. This can be proved by experiments. Two steel balls of the same size and quality and different hardness are made from the same material. The same height falls on the same steel plate. If the hardness of the steel plate is high, according to the principle of rigid body collision, the ball with high hardness rebounds high, the rebound of steel ball with low hardness is low, and the low rebound indicates that the steel plate has a large deformation, the steel plate The steel ball with high hardness and high hardness has a large and deep pit on the steel plate, that is, the energy of the ball is absorbed by the steel plate and converted into the deformation energy absorbed by the steel plate. A ball of low hardness causes the deformation energy of the steel sheet to be small because a part of the energy is absorbed by the steel ball.

3, 3 Due to the above two reasons, the early failure of the high manganese steel liner, the faster the deformation, the faster the failure time. The facts are just as valid.

Abstract 4.

Matrix analysis of failure causes of high manganese steel

The production mode of high-manganese steel is to obtain the matrix structure of the whole austenite by means of compounding, smelting and pouring, and to achieve the wear-resistant effect by the action of the steel ball. The energy, the surface is cold hardened, or under the action of the steel ball, the surface austenite transforms into surface martensite, and the hardness changes from Brinell hardness HB229 to HRc42 of Rockwell hardness, and then plays his Wear-resistance, but in the course of practice, it has been found through research that the linings removed from the steel-seeking mill have not been able to obtain a large amount of surface martensite structure after several years of operation, which is through the metallography. The microscope can be directly observed, only about 27% -49% of the available results, indicating that this technology design has inherent design flaws.

High manganese steel is not the best anti-wear material manufacturing product.

Abstract 4.

 According to the analysis of Abstract 3, we have found through in-depth research that during the transition from austenite to martensite, the volume of the two matrix structures is different, and the volume changes significantly. The phenomenon of volume expansion is the intrinsic reason for the volume expansion of high manganese steel liner. It is found through research that the elongation β is about 1.8%.

Taking the mill of DTM350/600 as an example, the circumference of the barrel of the mill is the combined elongation, and the calculated extension of the circumference is:

Π ×D ×β=3.14×1821 ×2×1.8% = 205.84mm

   The barrel of the ball mill is usually made up of 20~~40 steel plates. After prestressed plastic deformation, the extension space is very small and can be neglected. Therefore, the deformation of the lining plate is so large that it can be digested. The installation principle of the lining plate is to use the tightening Xiqi installation, and the extension space cannot be reserved. Therefore, as the microscopic stress increases continuously and the extension dimension increases, the reverse arch deformation of the lining plate will inevitably result in the drum package or along the cylinder. The bolt is broken in the direction of the body, causing the liner to fall off or fail.

The design of the new lining is based on the research of the lining defects and the design, material, installation, process improvement and technological innovation.