Material and Heat Treatment Method of Mining Coal Cutting Teeth

source：http://www.xrocktools.com/ Release Time：2015-07-09 09:44:53

Mining coal cutters are one of the vulnerable parts in coal mining and roadway excavation machinery, and are the main tools for breaking and shedding rock and coal seams. A tooth cutter is mainly composed of a tooth cutter handle, a tooth cutter head, and an alloy blade head. The tooth cutter handle and tooth cutter head are often referred to as the tooth cutter body. The hardness of the coal cutter body is 40 45HRC, and the impact toughness is not less than 49J/cm2. There are many types of mining coal cutters, and the general structure is to embed a hard alloy blade head on a low alloy structural steel blade body that has been quenched and tempered.

In the process of colliery operation, when the coal pick impacts the coal rock mass, the coal pick tip wedges into the coal rock body at a certain angle, so that the pressed part of the coal rock mass is gradually crushed. As the depth of the cutting teeth increases, the compressive force inside the coal rock gradually increases, causing the cross-section of the crushed coal rock to continuously expand. At the same time, the surface of the compressed area will undergo significant elastic deformation, causing the coal rock mass to fracture and form fan-shaped coal falling. The cutting teeth bear high cyclic compressive stress, shear stress, and impact load when cutting coal and rock. Although the hardness of coal is not very high, it often encounters hard mineral materials such as coal gangue. Friction and impact during the cutting process of coal and rock can also cause the temperature of the cutting teeth to rise. Cutting teeth that work under such complex working conditions require their blade body to be both wear-resistant and have good impact resistance.

The main failure modes of mining coal cutting teeth are tool head detachment, tool breakage, and tool head and body wear. Under certain working conditions, cutting teeth failure is often caused by tool body breakage. Due to the direct impact of the mechanical performance of the coal cutter body on the service life of the cutter, the reasonable selection of the material and effective heat treatment method of the coal cutter body has a positive significance in reducing the wear and breakage of the coal cutter body, reducing the consumption of coal mining machine cutters, improving the operation rate of coal mining machinery, and increasing the comprehensive economic benefits of coal mining production.

The commonly used material for coal cutting teeth is coal cutting teeth, which bear high cyclic compressive stress, shear stress, and impact load when cutting coal and rock. Although the hardness of coal is not very high, it often encounters hard minerals such as coal and rock. Friction and impact during the cutting process of coal and rock can also cause the temperature of the teeth to rise. Coal cutting teeth that work under such complex working conditions require their blade body to be both wear-resistant and have good impact resistance. The coal cutter body is generally made of low-alloy structural steel.

From the actual use of imported and domestically produced coal cutters in some domestic coal mines, the material of the cutter body is mostly 42CrMo, 35CrMnsi and other steel grades. Some coal mines are also using the newly developed Si-M-MO quasi bainitic steel in China.

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