-
-
-
-
Honor
-
-
-
-
-
Contact
-
The method of improving the reliability of the pick and reducing the loss of the pick.
Release time:
2019-10-21
Author:
Source:
cutting pickIt is one of the vulnerable parts in coal mining and roadway driving machinery, and it is the main tool for coal falling and coal crushing. The cutter used on the drum of the shearer and the roadheader is usually called the pick. The pick is a vulnerable part that needs to be replaced frequently, which has a certain impact on the cost per ton of coal. Therefore, it is of great significance to improve the quality, reliability, strength, life and working performance of the pick, correctly select and install the pick, improve the production efficiency of the shearer and reduce the cost.
The performance of the pick directly affects the production capacity of coal mining machinery, power consumption, work stability and other related parts.Service life. There are many types of cutting teeth, the general structure is in the quenching, tempering treatment of low alloy structural steel cutter body inlaid with carbide cutter head. The pick is subjected to high periodic compressive stress, shear stress and impact load during operation. The main failure forms are head shedding, chipping and headThe cutter body is worn, and under certain working conditions, the cutting tooth is often failed due to the breakage of the cutter body. Due to the mechanical properties of the cutting tool bodyThe service life of the pick is affected, so the material of the pick cutter body and the effective heat treatment method are reasonably selected to reduce the wear and tear of the pick cutter body.cutting, reducing the consumption of shearer pick, improving the operation rate of coal mining machinery, and increasing the comprehensive economic benefits of coal mining production, all have positive significance.
The pick is a vulnerable part of mining machinery, through long-term analysis and research on the pick, from the selection of new pick, pick arrangement and pick structure.Improvement and other aspects of the reliability of the shearer pick a simple analysis. Improve the reliability of the pick and reduce the ratio of tooth consumption to the cost of coal per ton.example, to improve the effective working time of the shearer. The reliability of the shearer pick and the factors of the pick itself, the factors of the shearer, the conditions of coal seam occurrence, etc.A variety of factors.
Representation of reliability of 1. pick
The reliability of the cutting tool refers to the ability of the tool to complete the rated work within the specified cutting conditions and time. Fault shutdown causes pick generationFailure to work. For example: gradual tool wear; sudden wear and loss, etc. Wear failure is the positive of tooth depreciation.regular form. The pick is generally easier to maintain and regrind, and can be used for a period of time after repair and regrinding. The total use time of the tool isis the total service life.
The reliability of the pick is characterized by a certain average quantity and randomness. Therefore, the study of tool reliability using mathematical statistics andProbabilistic analysis methods.
Probability of cutting tooth working without failure during Lj wear length
P(Lj)=∑KiPi(Lj)
Where Pi(Lj)-the probability of no failure under the I failure form;
I-different failure forms (such as wear failure; Hard disassembly failure; Lost failure);
Ki-failure probability coefficient (k is the largest when worn and k is the smallest when lost).
The above through a large number of statistics, the formation of guiding literature. For example, wear accounts for 80%, breakage accounts for 15%, loss accounts for 5%, and the total probability is obtained cumulatively.。
2. Ways to Improve the Reliability of Cutting Teeth
(1) The effect of adopting new type shearer pick
The new pick can increase the load on the working face by 6%-8%. The cutting area reaches 18-30 cm2 when the work is stable, and the energy consumption can be reduced.8%-32%, the feed speed can be increased by 15%-40% when working at full load. The adoption of a new type of pick can make the coal mined by the shearer large and reduce the size of the coal.Dust, improve working conditions, significantly reduce the consumption of cutting teeth. Compared with U90B, the consumption of radial pick 3P1-80 can be reduced by 50%-70%The hard alloy on this pick is also reduced to a minimum, and the consumption of hard alloy in mass production only accounts for 65%-85%. Durability of new pickFor example, PKC -1 and PKC -2 are 1.5-2.5 times higher than radial picks U90M5 and U796, and the consumption of hard alloy is reduced by 1 time.
The requirements for the new pick should be based on the determined quota, and the repair and use of the pick should also be considered.
New pick consumption quota Nx = ∑ NiQi-KBNB
In the formula Ni-new pick unit consumption quota;
Qi-planned coal mining volume, Qi = 1,000 t;
KB-Reduce the durability coefficient of the pick when the pick is repaired;
KB=0.7―0.9;
NB-Number of picks repaired.
(2) Increase the number of tangential picks and reduce the installation of radial picks. The ideal is that the direction of the resultant force on the picks should coincide with the tooth body, otherwise it will come out.Now the tooth body interferes with the coal body that has not been cut off, which will significantly increase the cutting resistance, and the contact extrusion between the tooth body and the coal body will undoubtedly increase the amount of pulverized coal,The wear of the pick is aggravated, the service life of the pick is reduced, and the tooth consumption is increased.
The length of the tangential pick is large, and its strength is large due to the good distribution of force, and the thickness of the cut coal is large. At the same time, because the direction of the force is related to the knifeWith the same axis, the cutter teeth are not subject to bending force, so the amount of carbide can be reduced. The radial pick is poorly stressed and worn, and the number used is required.A little less. Radial pick to increase the length of the cut, can increase the cross-sectional area of the cutter body, and the use of thick carbide block, not only improve its strengthIt can also be continuously ground in use. Blunt cutting teeth can be reground (usually 2-3 times), which can save cutter teeth.
(3) Adopt cutting teeth that can be rotated
Because the diameter D of the cutter head is larger and the diameter of the fixed shaft D is smaller, the cutter teeth are easy to rotate and cutDuring cutting, the rotation of the cutter teeth will automatically sharpen the tip of the cutter and increase the life of the cutter. At the same time, in order to make the carbide firm, the carbide will not fall off due to wear., so that the tip part of the knife body material is not easy to wear. Therefore, flame spraying or plasma spraying is adopted around the carbide to increase the life and improve the cutting tooth.The wear resistance. Swivelablecutting pickThe structure is simple, easy to manufacture, and is widely used.
Through the above method can greatly improve the reliability of the shearer pick, reduce the loss of the pick, significantly improve the utilization rate of the shearer, reduceLow tooth consumption accounts for the proportion of coal cost per ton.
Key words:
