Cutting tooth is the cutting tool used in coal mining, roadway tunneling and tunnel construction.In recent years, under the background of the increasing demand of coal in China and the wide application of high-power fully mechanized mining machinery in coal mining, the demand and loss of cutting teeth are huge.In order to improve the reliability and service life of the cutter, the following measures are usually adopted:
1. New materials
In order to meet the development requirements of coal mining machinery and solve the problems of poor wear resistance and tooth head easy to fall off of cemented carbide cutting teeth produced by the existing technology, some new alloy steels are being gradually applied to the production of cutting teeth, such as air-cooled bainite steel, new series of quasi-bainite steel and high toughness secondary hardened steel.
2. Integrated technology of brazing and heat treatment
Due to the characteristics of small deformation and simple process, brazing is often used in the connection between carbide tool head and tooth body.To copper base as a solder, the brazing temperature range between 880 ~ 950 ℃, the residual stress is larger, and need to secondary heat treatment after the tooth body can give full play to its comprehensive performance.
3. Surface enhancement of the truncated teeth
1) thermal spraying technology
By spraying a layer of high hardness and wear resistant alloy which can be highly combined with the tooth body, the hardness and wear resistance of the tooth can be greatly improved, and its service life can also be improved.
2) cladding technology
Cladding is to modify or repair the surface of coating materials by combining them with the substrate.Laser cladding is a kind of metallurgical additive cladding layer which is formed by melting the coating material and the substrate surface material simultaneously by high-energy laser irradiation.
3) surfacing welding coating technology
By means of surfacing welding technology, the coating structure of Cr, W and V alloy on the cutting head is similar to tungsten alloy steel, which can greatly improve the wear resistance, corrosion resistance and impact resistance of the cutting teeth.
4) surface chemical heat treatment technology
Surface chemical heat treatment is a technology to obtain a layer of high-performance special composite material by means of different chemical reactions on the surface of the material. Because the failure and damage of the cutting tooth mainly germinate in the surface layer, after chemical heat treatment can greatly improve the anti-bonding wear and anti-corrosion of the cutting tooth.