Cemented carbide cutting picks are generally divided into two types: cutter teeth (also called radial teeth) and pick teeth (also called tangential teeth).

The pick shape cutter tooth structure is simple, can click on the coal, turning deep, automatic sharpening, often in the course of work keep sharp teeth, coal winning machine load is relatively stable, so than knife cut tooth less energy consumption, long life, and small amount of coal dust, coal quantity is big, suitable for use in hard coal.

In a spiral drum coal mining machine, the gear cutting motion on the spiral drum is the combined motion of the rotation of the spiral drum and the horizontal swing of the cutter arm.

Trajectory for plane of cycloid, this work is divided into a cone, while working as picks wedge into the coal and rock, carbide cutter tooth wedge into the coal and rock in an instant, tooth cone surface of coal and rock pressure exceeds the compressive strength of the coal, the coal and rock crushing, as the pick shape of the cutter tooth wedge, the tension of coal rock mass is more and more big, until pick shape cutter teeth around the segment from the coal and rock breaking down.

The cutting teeth bear high pressure stress, shear stress and impact load when cutting coal rock. Coal hardness is not high, but there are coal gangue and other hard mineral aggregate, and in the process of coal mining and drilling, cutting tooth temperatures will rise sharply, leading to tooth top material softening, accelerate the failure process of the cutter tooth.

Cutter tooth in the process of work, the abrasive (gangue, etc) between the cutter tooth surface and produce larger compressive stress, with sharp edges and has a right Angle abrasive cutting cutter tooth surface formation micro cutting. If the grinding grain is not sharp enough or the Angle is not appropriate, the furrow will be forced out on the surface of the cutter tooth.

With the extension of cutter tooth working time, the abrasive surface of cemented carbide cutting picks push repeatedly, severe plastic deformation of the flow, make the surface of the lower interact, increase plastic deformation dislocation density in the area, surface crack, crack extension, foliated chip cutter tooth surface formation.

And corrosive medium exist in the coal seam and cutter tooth surface chemical reaction caused by the surface material corrosion, mechanical performance, and reduce the surface metal bonding force with substrate material, speed up the cutter tooth material surface wear.

In addition, when cutting tooth cutting coal and rock, bear the impact load of high intermittent, under the action of impact load, the cutting tooth surface harder micro convex point deformation, repeatedly squeezed in nearby soft surface to produce plastic flow and in cutting tooth surface formation accumulation, again and again of elastic-plastic deformation, and the dislocation concentrated, which in turn micro cracks appear on the surface transverse. After wear, the area of the cutting part increases, which increases the cutting resistance and reduces the cutting strength.

When the cutter head is worn to a certain extent, the carbide tip will fall off. The cutting teeth after the tip of the hard alloy teeth have been completely invalid. A large number of statistical analysis showed that the failure modes in accordance with the degree of order are: cutting teeth tooth head wear after cemented carbide tooth loss, broken tooth, tooth body bent or broken, the cutting tooth tooth head wear failure of tooth loss about 85%.

So, in order to improve the service life of cemented carbide cutting picks, first of all to ensure gear tooth surface has enough head of wear-resisting, corrosion resistant, shock resistance, at the same time increase the cutting tooth the tooth body strong toughness (using biya cutter tooth processing equipment, cutting teeth, welding equipment, cutting gear quenching equipment), can effectively extend the service life of cutting teeth.

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