Extraordinarily-coarse grain hard alloy and preparation method thereof

Abstract

The invention relates to an extraordinarily-coarse grain hard alloy and a preparation method thereof. The extraordinarily-coarse grain hard alloy comprises the following effective raw materials of tungsten carbide powder with the average grain size being 30-45 [mu]m, cobalt powder with the average grain size being 2-4 [mu]m, tungsten powder with the average grain size being 2-3 [mu]m, ethyl alcohol with the purity being 99.8% or above, and powdery paraffin with the melting point being 52-54 DEG C; the weight proportion of the part, with the grain size being smaller than 5 [mu]m, in the tungsten carbide powder is smaller than or equal to 1%, the purity of the tungsten carbide powder is 99.8% or above, the oxygen content of the tungsten carbide powder is 0.03% or below, the iron content of the tungsten carbide powder is 0.03% or below, the content of combined carbon in the tungsten carbide powder is 6.02%-6.04%, and the content of free carbon in the tungsten carbide powder is 0.06% or below; the purity of the cobalt powder is 99.7% or above, the oxygen content in the cobalt powder is smaller than 0.5%, the iron content in the cobalt powder is smaller than 0.02%, and the carbon content in the cobalt powder is smaller than 0.03%; and the purity of the tungsten powder is 99.9% or above, and the oxygen content in the tungsten powder is 0.2% or below. The grain size of the extraordinarily-coarse grain hard alloy is large and completely meets the standard of the extraordinarily-coarse grain hard alloy.

Description

technical field [0001] The invention belongs to the technical field of hard alloy processing, and relates to an ultra-coarse-grain hard alloy, in particular to an ultra-coarse-grain hard alloy and a preparation method thereof. Background technique [0002] Cemented carbide is an alloy material made of hard compounds of refractory metals and bonding metals through powder metallurgy. Cemented carbide has a series of excellent properties such as high hardness, wear resistance, good strength and toughness, heat resistance and corrosion resistance, especially its high hardness and wear resistance, which basically remain unchanged even at a temperature of 500°C , It still has a high hardness at 1000°C. The excellent properties of cemented carbide make it widely used as tool materials, such as turning tools, milling cutters, planers, drills, boring tools, etc., for cutting cast iron, nonferrous metals, etc. Metal, plastic, chemical fiber, graphite, glass, stone and ordinary steel ...

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Problems solved by technology

[0005] Although my country's total output of cemented carbide ranks first in the world, accounting for more than 40% of the world's total output, the market share of high-performance cemented carbide for shearer and shield machine cutter heads is still less than 2%. The quality of cemented carbide products for coal mining and shield machine cutter heads is still more or less problematic, and it is difficult to be generally recognized by the industry. There is no cemented carbide company that can stably produce and supply coal shearers and shield machines. The high-performance cemented carbide used for the cutter head mainly has the problems of uneven grain size, small grain size, contradictory wear resistance and impact toughness of cemented carbide, and can only be balanced by cobalt content. While the processing cost of cemented carbide is high, it cannot meet the requirements of ultra-coarse-grained cemented carbide

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