Submicron hard alloy and preparation method

Abstract

The invention discloses a submicron hard alloy and a preparation method thereof. The alloy comprises the following components in percentage by weight: 7 to 9 percent of C, 0.2 to 0.5 percent of Cr3C2, 0.1 to 0.4 percent of VC, and the balance of WC of 0.7-0.9 mu m. The preparation method comprises the steps of material blending, wet grinding, drying, forming and sintering, wherein the ratio of grinding media to material of the wet grinding is (4.5-6):1, the rotating speed of a wet grinder is 30 to 40 revolutions per minute, and the grinding time is 28 to 45 hours; a mixed material is dried, a molded blank is sintered at the temperature of between 1,400 and 1,450 DEG C, the sintered pressure is between 58 to 100 bar, and the heat insulation time is 30 to 60 minutes; and the WC grain size in the alloy is 0.7 to 0.9 mu m, the hardness is HV31730-1860, and the bending strength is not smaller than 4,000N/mm<2>. A cutting tool manufactured by using the alloy can also ensure enough strength and flexibility while increasing the abrasion resistance, can meet requirements on high efficiency and high durability of the cutting tool, is used in the fields of cutting cast irons, aluminum alloys and non-ferrous metals and drilling steel pieces, and can realize large-scale industrial production.

Description

technical field [0001] The invention relates to a hard alloy and a preparation method thereof, in particular to a hard alloy with a grain size in the range of 0.7-0.9 μm, which has excellent wear resistance, toughness and high bending strength, and is suitable for drilling and reaming cutting with high performance. Submicron cemented carbide and its preparation method. Background technique [0002] Modern cutting technology requires high efficiency, high durability and high reliability of cutting tools. Cemented carbide has a wide range of uses in the field of cutting tools due to its high hardness and high strength. With the emergence of submicron and ultrafine cemented carbide, its unique "double high" characteristics compared with ordinary The field of cutting has been widely used industrially. Submicron and ultrafine cemented carbides have different material properties depending on the Co content and the grain size, and are suitable for application in different fields ...

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Problems solved by technology

The hardness of the above grades is not more than HV 3 1650, its wear resistance cannot meet the requirements of modern cutting technology

[0004] The ultra-fine-grained WC-Co cemented carbide preparation method mentioned in the Chinese patent application "A preparation method of ultra-fine-grained WC-Co cemented carbide (200710120263.6)", due to the ultra-high pressure sintering method adopted, and the sintering time is only 60-120 seconds, which makes the growth of WC grain shape incomplete, which is not conducive to the elimination of internal defects of WC grain; using six-sided top ultra-high pressure sintering equipment, it is difficult to manufacture complex or specific-shaped cemented carbide products, and the single batch output is low. It cannot adapt to multi-model, high-efficiency, large-scale modern industrial production, and there has been no industrial application report so far

[0005] The ultra-fine-grain cemented carbide material mentioned in the Chinese patent application "ultra-fine-grain cemented carbide material (200410045029.8)" is used in the field of cutting cast iron, aluminum alloy, non-ferrous metals, especially steel parts, due to The grain size (0.5μm) of the cemented carbide material is too fine, although the hardness can meet the requirements, but its fracture toughness (Kic) is insufficient, and it is easy to cause the tool to break and break during use

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