In the production of steel wire, the consumption oftungsten carbidedrawing diesarebroken and worn. Broken molds can only be scrapped, worn molds can be repaired and reused, so the proportion of broken molds should be reduced as far as possible in production.

According to statistics, the form of core failure is:

(1) longitudinal crack, 75% of the broken mold is longitudinal crack, 90% of which is normal damage caused by the thinning of mold core wall after repeated grinding, only a small part is caused by excessive drawing surface reduction rate, dirty cleaning of steel wire surface oxide skin, bad coating and bad mold mounting;

(2) transverse crack, which accounts for about 13% of the total, is mainly caused by bad mold setting, such as excessive taper or non-roundness of the mold core and poor contact between the mold core and the bottom surface of the mold cover. Drawing surface reduction rate is too large, poor lubrication is the secondary cause;

(3) crack and outlet end meat broken

Crack accounted for 6%, mold material defects and improper wire drawing process accounted for half, meat is mainly mold quality problems.

Die hole wear has three forms:

(1) rough surface.

The deformation heat caused bytungsten carbide wire drawingdiescauses the temperature of the mold to rise, and the oxidation color appears locally, causing slight wear. Poor lubrication results in spot-like welding between steel wire and die hole surface, loose and displacements of tungsten carbide particles, scratches and ripples, rough surface of working cone and diameter belt, and large wear.

(2) the ellipse.

The hardness of hard alloy is not uniform, the drawing direction does not coincide with the axis of the die hole, and the single side of the die hole is subjected to force, resulting in ellipse.

(3) annular groove. It is a typical fatigue wear. In the process of wire-drawing, the die hole continuously bears the impact of the wire material, which loosens and falls off the tungsten carbide particles and forms a rough surface. The rough surface scrapes off the metal scraps from the surface of the steel wire, which worsens the lubrication conditions and accelerates the wear rate.

From oxidation discoloration to surface roughness to the appearance of annular grooves is the process of increasing wear. The way to use the mould reasonably and extend its life is to wear it in time and change the mould before the annular groove appears in the mould hole. The mold should be cleaned and checked in time after each use. If the surface is slightly worn, it can be used as the process mold by direct polishing or fine grinding and polishing. The grinding amount of the mold should be controlled at the minimum level as far as possible, and the number of times of repair and reuse of the mold should be increased. According to GB/T 61 10 regulation, when the die hole diameter is close to the size of the die blank maximum aperture, more attention should be paid to check the die hole surface, even if there are slight lines to scrap, to prevent the waste steel wire. Die life is usually 0. When 01mm pull out the number of meters or quality of the steel wire to measure, pull medium specification (diameter 4.0mm) special steel wire, the life value of the hard alloy die generally can reach 300,000 m / 0. 01 mm and above. Die consumption is usually expressed by the amount of hard alloy die core mass consumed per ton of steel wire, and the die consumption index of special steel wire is about 150 -- 250 g/t.

Related link:

http://www.wococarbide.com/Library/libraryinfo/id/1481

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