Sintering method for low-stress hard alloy mold material

A mold material and cemented carbide technology, which is applied in the field of low-stress cemented carbide mold material sintering, can solve the problems of particle increase and decrease, and achieve the effect of low production cost, improved ability, and passivation of WC sharp corners.

Active Publication Date: 2021-10-22
九江金鹭硬质合金有限公司
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  • Abstract
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  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The WC-Co-(Ni)-(C)-(V) cemented carbide with a Co(Ni) binder mass fraction higher than 20ωt% will be hardened even at 1300-1320°C and the holding time is 10-40min. Because the amount of liquid phase is large, the dissolution and separation reaction of WC particles is violent, resulting in a sharp increase in particles, resulting in a decrease in hardness, wear resistance and strength, which is not suitable for the method of the present invention.

Method used

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  • Sintering method for low-stress hard alloy mold material
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  • Sintering method for low-stress hard alloy mold material

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Embodiment 1

[0026] WC-13.0ωt% Co cemented carbide mold material, the original WC particle size is 1.0 μm, and the appearance size is 105mm × 105mm × 50mm. One piece is sintered by conventional technology, and the other is sintered by the method of the present invention. The specific steps of sintering by the method of the present invention are as follows: :

[0027] 1) Hydrogen positive pressure dewaxing: put the mold material plate compact containing the forming agent on the graphite plate coated with anti-stick high temperature coating and put it into the furnace with a volume of 0.1m 3 The dewaxing-sintering integrated low-pressure furnace is heated from room temperature to 350°C at a heating rate of 1.8°C / min, and kept at a temperature of 700 minutes and then continued to rise to 650°C at a heating rate of 1.8°C / min. The hydrogen flow rate is controlled at 35SLM throughout the process. The furnace pressure is controlled at 10mbar.

[0028] (2) Nitrogen dehydrogenation: After step (1)...

Embodiment 2

[0041] WC-16.0ωt% Co cemented carbide mold material, the original WC particle size is 3.0 μm, and the appearance size is 150mm × 150mm × 60mm. One piece is sintered by conventional technology, and the other is sintered by the method of the present invention. The specific steps of sintering by the method of the present invention are as follows: :

[0042] 1) Hydrogen positive pressure dewaxing: put the mold material plate compact containing the forming agent on the graphite plate coated with anti-stick high temperature coating and put it into the furnace with a volume of 0.1m 3 The dewaxing-sintering integrated low-pressure furnace is heated from room temperature to 350°C at a heating rate of 1.2°C / min, and kept at a temperature of 800 minutes, and then continues to rise to 650°C at a heating rate of 1.2°C / min. The hydrogen flow rate is controlled at 35SLM throughout the process. The furnace pressure is controlled at 10mbar.

[0043] (2) Nitrogen dehydrogenation: After step (1...

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Abstract

The invention discloses a sintering method for a low-stress hard alloy mold material. The sintering method comprises the following steps of hydrogen positive-pressure dewaxing, nitrogen hydrogen discharging, vacuum sintering, low-pressure sintering, cooling for the first time, re-burning for destressing and cooling for the second time; in the step of re-burning for destressing, firstly, the temperature is increased to 1200 DEG C and kept, and secondly, the temperature is increased to 1300-1320 DEG C and kept; and in the step of cooling for the second time, natural furnace cooling to 60 DEG C or below is carried out, and then discharging is carried out to obtain a low-stress hard alloy mold material product. The method has the advantages that equipment such as an annealing and tempering furnace, a subzero treatment furnace and a grinding machine and corresponding workloads do not need to be additionally added, and the sintering stress of the product can be effectively reduced and the fracture toughness of the product can be improved by adding the steps of re-burning for destressing and cooling for the second time in an original dewaxing-sintering integrated low-pressure furnace.

Description

technical field [0001] The invention relates to the field of production and manufacture of cemented carbide mold materials, in particular to a sintering method for low-stress cemented carbide mold materials. Background technique [0002] Most of the cemented carbide mold materials are (100~250)mm×(100~250)mm×(1.0~60.0)mm plates, which are made into punches, dies, etc. Carbide parts are used for the wear-resistant and impact-resistant parts of the progressive die to stamp silicon steel, stainless steel, alloy copper and other thin strips at a speed of 200 to 800 times / min at a high speed. Because the thermal expansion coefficient of Co, the main component of cemented carbide, is close to three times that of WC, and the size of the cemented carbide mold material plate is too large, under the conventional sintering process conditions, the internal and surface cooling rates of the cemented carbide are inconsistent, resulting in internal residual The sintering stress is large, a...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B22F3/10B22F3/24C22C1/05C22C29/08
CPCB22F3/1021B22F3/24C22C1/051C22C29/08C22C29/067B22F2003/248
Inventor 孙东平杜伟刘宾刘勋刘诗彪叶楠敏
Owner 九江金鹭硬质合金有限公司
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