cutting tool-alloy tool,high-speed steel tool

cutting tool-alloy tool,high-speed steel tool

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In addition to abrasive wear and cold wear, diffusion wear, oxidation wear is also the main cause of cutting tool wear.

Diffusion wears produced at high temperature. Metal cutting, cutting, workpiece and tool in the process of contacting chemical elements mutual diffusion in the solid state, changed the composition and structure of the original materials, the tool material becomes fragile, thereby increasing the tool wear of hard alloy cutting steel. For example, from the beginning of the 800 C the chemical elements in cemented carbide, quickly spread to the chip, workpiece to WC decomposed into W and C spread to the steel. Because of the chip, the workpiece in high speed, the tool surface, and their surface maintained a concentration gradient diffusion of elements in the contact area, so that the diffusion phenomenon continues. Then, the carbon depleted hard alloy surface, poor tungsten phenomenon. The binder CO is reduced, and the cemented carbide hard phase (WC, TiC) to reduce the bond strength of the chip, workpiece in Fe to the hard alloy diffusion, diffusion to the hard alloy in Fe, will form a new The hardness of composite carbide, high brittleness. All these make the tool wear intensified. In addition to the cutting tool, workpiece material properties other than their own, the temperature is the main influencing factor of diffusion wear. Diffusion wears often with cold welding wear, abrasive wear is produced at the same time, the wear rate is very high. High-speed steel tool working temperature is low. With the chip, the diffusion between the workpiece is slow, so the diffusion wear proportion is far less than the hard alloy cutter.

The so-called oxidation wear, is when the cutting temperature reaches 700 to 800 DEG C, the oxygen in the air with cobalt and tungsten carbide hard alloy, titanium carbide oxidation, produce soft oxide (such as Co3O4, CoO, WO3, TiO2) is cut off or the workpiece and the formation of wear debris and this is called oxidation wear and oxidation wear. The adhesion strength of the films, the adhesion strength is low, then wear more quickly; otherwise, it can reduce the wear. In general, the air is not easy to enter the tool chip contact area, formation boundary in the main cutting edge of the auxiliary cutter wear most easily oxidized.


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