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Hard alloy for cold heading mold and preparation method thereof

A hard alloy and mold technology, applied in the field of hard alloy preparation, can solve the problems of limited alloy toughness, sacrifice wear resistance, etc., achieve long service life, improve comprehensive performance and service life, and improve corrosion resistance.

Active Publication Date: 2015-03-04
ZHUZHOU HARD ALLOY GRP CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In general, these methods have limited improvement in alloy toughness, and on the premise of sacrificing wear resistance, they cannot solve the contradiction between the two.

Method used

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  • Hard alloy for cold heading mold and preparation method thereof
  • Hard alloy for cold heading mold and preparation method thereof
  • Hard alloy for cold heading mold and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] A hard alloy for cold heading dies, used for cold heading stainless steel Φ4.8 screw straight rods, the alloy and weight percentage of the composition are: Co powder 25%, WC powder with Fsss particle size 2.0-3.0μm 74%, 1.5μm Cr 3 C 2 1%.

[0024] The preparation method of above-mentioned cemented carbide for cold heading die: get above-mentioned raw material in proportion, and gross weight is 50KG, puts into 50 liters of tiltable ball mills, does wet-milling medium with alcohol and carries out wet-milling, and ball-to-material ratio is 4.3: 1. The liquid-solid ratio is 330ml / KG. Add paraffin wax molding agent according to 2% of the total weight of the raw materials. The wet grinding time is 50h. After the wet-milled slurry is spray-dried and pressed, it is sintered in a PVA furnace at 58bar. The temperature is 1410° C., and the holding time is 60 minutes to obtain a sintered cemented carbide.

[0025] Carry out heat treatment on the cemented carbide obtained after ...

Embodiment 2

[0027] A hard alloy for cold heading dies, used for cold heading carbon steel Φ3.8 screw straight rods, the alloy and weight percentage of the composition are: Co powder 22%, WC powder with Fsss particle size of 5.0-6.0μm 77.5%, 1.5 μm Cr 3 C 2 0.5%.

[0028] The preparation method of above-mentioned cemented carbide for cold heading mold: get above-mentioned raw material in proportion, and gross weight is 50KG, puts into 50 liters in the tiltable ball mill, does wet-milling medium with alcohol and carries out wet-milling, and ball-to-material ratio is 3.4: 1. The liquid-solid ratio is 320ml / KG. Add paraffin wax molding agent according to 2% of the total weight of the raw materials. The wet grinding time is 36 hours. After the wet-milled slurry is spray-dried and pressed, it is sintered in a PVA pressure furnace at 58bar. The sintering temperature is 1450° C., and the holding time is 60 minutes to obtain a sintered cemented carbide.

[0029] Carry out heat treatment to the ...

Embodiment 3

[0031] A hard alloy for cold heading dies, used for cold heading stainless steel Φ8 screw straight rods, the alloy and weight percentage of the composition are: 28% Co powder, 70.5% WC powder with Fsss particle size of 3.0-4.0 μm, 1.5 μm Cr 3 C 2 1.5%.

[0032] The preparation method of above-mentioned cemented carbide for cold heading mold: get above-mentioned raw material in proportion, gross weight is 50KG, puts into 50 liters in the tiltable ball mill, does wet-milling medium with alcohol and carries out wet-milling, and ball-to-material ratio is 4.5: 1. The liquid-solid ratio is 350ml / KG. Add paraffin wax molding agent according to 2% of the total weight of raw materials. The wet grinding time is 52 hours. After the wet-milled slurry is spray-dried and pressed, it is sintered in a TP furnace (no pressure). The sintering temperature is 1400° C., and the holding time is 60 minutes to obtain a sintered cemented carbide.

[0033] Carry out heat treatment to the cemented carbi...

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Abstract

The invention discloses a hard alloy for a cold heading mold and a preparation method thereof. The preparation method comprises the following steps: mixing the following materials in percentage by weight: 22-28% of Co, 70.5-77.5% of WC and the balance of Cr3C2, wherein the Fsss particle size of WC is 1.0-6.0 mu m; and then, performing wet grinding, drying, performing pressure molding, sintering, quenching, and tempering. For a hard phase of the hard alloy prepared by the method disclosed by the invention, the average grain size is 1.2-2.0 mu m, the hardness is 84.0-86.0HRA, the bending strength is above 3100 MPa, and the alpha-Co content is high; the toughness and corrosion resistance of the alloy are favorable; Cr3C2 is almost completely dissolved in the Co phase, thus further strengthening the Co phase and reinforcing the stability of the alpha-Co phase; and transition of alpha-Co to epsilon-Co is inhibited in the use process, thus greatly increasing the comprehensive properties and service life of the hard alloy.

Description

[0001] technical field [0002] The invention relates to a method for preparing cemented carbide, in particular to a method for preparing cemented carbide used for cold molds. Background technique [0003] Because of its high strength and high hardness, cemented carbide is widely used in the fields of forming molds, cutting tools, mining tools and wear-resistant parts. At present, cemented carbide is widely used as a forming die at home and abroad for cold heading standard and non-standard fasteners, such as nuts, bolts and screws. Because in this working state, the forming punch bears a large impact force, the impact frequency is very high, in addition to a certain working temperature, and the use environment is relatively harsh, which requires the cemented carbide mold to have high strength, high resistance Abrasive, but also have a certain corrosion resistance. At present, the difficulty in preparing cemented carbide cold heading dies is how to unify high strength and h...

Claims

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Application Information

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IPC IPC(8): C22C29/08C22C1/05C22F1/00
CPCB22F2003/248C22C1/051C22C29/005C22C29/08
Inventor 尹超郭建中任跃
Owner ZHUZHOU HARD ALLOY GRP CO LTD
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