Dewaxing and sintering integrated technique for large product of hard alloy

Abstract

The invention discloses a dewaxing and sintering integrated process for a large hard alloy product, which comprises the following steps: firstly, argon is filled in a furnace, then the argon is replaced by hydrogen, and the pressure in the furnace is controlled at 1.01 multiplied by 10<5> Pa to 1.03 multiplied by 10<5> Pa; the step type heating and heat preservation are implemented under the condition that the hydrogen flow is 240 L / min to 260 L / min, and a paraffin forming agent is eliminated; the atmosphere in the furnace is adjusted as a negative pressure during the heat preservation periodafter the temperature is increased to 450 DEG C, and the residual paraffin forming agent in the furnace is eliminated through adopting the hydrogen pulse pressure to scour; after the paraffin formingagent is eliminated, the temperature is increased to 1300 DEG C to 1350 DEG C for vacuum sintering; the argon is filled in the later period of the vacuum sintering, and the argon protection sinteringis carried out at the temperature of 1350 DEG C to 1450 DEG C; and the rapid cooling is performed after the argon protection sintering is completed. The invention has the advantages that the step type heating and heat preservation are performed under the micro-positive pressure hydrogen atmosphere, the dewaxing efficiency is high, the product can not crust, the carbon content control precision ofthe product is very high, and the alloy cobalt magnetism value reaches 6.8 percent to 7.2 percent after the hold-up hammer sintering.

Description

technical field [0001] The invention relates to a process method of dewaxing and sintering in hard alloy production, in particular to a method for preparing large hard alloy products through an integrated process of dewaxing and sintering. Background technique [0002] In the compression molding of the production of large cemented carbide products, paraffin wax molding agents must be mixed. However, the molding agent (ie dewaxing) must be removed before the sintering of the cemented carbide products. Usually, two modes are used to complete the removal of the molding agent. The first The first is the batch type, that is to use specific special equipment to complete the removal of the paraffin molding agent at a temperature of 600-800 ° C and a hydrogen protective atmosphere, and then the product is cooled and then transferred to a sintering furnace to complete sintering. The second is the continuous integrated type, that is, the molding agent removal and sintering process of ...

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Problems solved by technology

[0003] The purpose of the present invention is to overcome the technical defect of insufficient carbon content control accuracy in the sintering process of large cemented carbide products mixed with paraffin wax molding agent in the above two methods of removing the molding agent, and proposes a method that realizes The new dewaxing and sintering integrated process for removing the forming agent in large cemented carbide products can realize high-precision control of the carbon content in large products and improve product quality and production efficiency

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