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A production process for large-sized carbide valve balls above φ80

A cemented carbide and production process technology, applied in the field of cemented carbide valve ball production process, can solve the problems of increased scrap rate, low molding efficiency, uneven density of finished balls, etc., and achieve the effect of eliminating residual stress

Inactive Publication Date: 2017-12-29
四川欧曼机械有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The cemented carbide valve balls produced by this powder metallurgy process generally have the following problems: (1) low molding efficiency; (2) uneven density of finished balls
Especially when the diameter of the ball exceeds 80mm, the reject rate increases greatly. At present, there is no mature mass production process report for valve balls larger than φ80mm at home and abroad.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0031] This experiment needs to process a cemented carbide valve ball with a diameter of 100mm, using a series of titanium-based formulas, including: TiC: 81.5%, binder: 5.5%; grain inhibitor: 7.5%; reinforcement: 1%; Toughening agent: 1%, the rest is unavoidable impurities, put it into the stirrer and stir at a constant speed, the stirring speed is 1000r / min, the stirring time is 5 minutes, and the temperature is controlled between 20°C and 25°C;

[0032] After the stirring is completed, the stirred raw materials are sent into a static press, and placed on a built-in steel frame for pressing. The set pressure for pressing is 155 MPa, and the static pressing time is 4.5 minutes.

[0033] The pressed valve ball is sintered by vacuum sintering process. Vacuum sintering can better remove Si, Mg, Ca and other oxide impurities in the sintered body, thereby improving the purity of cemented carbide. At the same time, the gas phase under vacuum The carburizing and decarburizing effect...

Embodiment 2

[0042] This experiment needs to process a cemented carbide valve ball with a diameter of 80mm, using a nickel-based series formula, including: WC: 83%, hydroxynickel powder: 8%; grain inhibitor: 7%; reinforcing agent: 1%, remaining The unavoidable impurities are placed in a stirrer for constant stirring, the stirring speed is 1000r / min, the stirring time is 5 minutes, and the temperature is controlled between 22°C and 25°C;

[0043] After the stirring is completed, the stirred raw materials are sent into a static press, and placed on a built-in steel frame for pressing. The set pressure for pressing is 155MPa, and the static pressing time is 4 minutes.

[0044]The pressed valve ball is sintered by vacuum sintering process. Vacuum sintering can better remove oxide impurities such as Si and Ca in the sintered body, thereby improving the purity of the cemented carbide, and at the same time, the infiltration of the gas phase under vacuum The carbon and decarburization effects are ...

Embodiment 3

[0049] This experiment needs to process a cemented carbide valve ball with a diameter of 90mm, using a cobalt-based series formula, including: WC: 59%, Ni: 12%, Co: 30%, and the rest are unavoidable impurities, put into the stirring Stir at a constant speed in the container, the stirring speed is 800r / min, the stirring time is 5 minutes, and the temperature is controlled between 22°C and 25°C;

[0050] After the stirring is completed, the stirred raw materials are sent into a static press, and placed on a built-in steel frame for pressing. The set pressure for pressing is 145 MPa, and the static pressing time is 3 minutes.

[0051] The pressed valve ball is sintered by vacuum sintering process. Vacuum sintering can better remove oxide impurities such as Si and Ca in the sintered body, thereby improving the purity of the cemented carbide, and at the same time, the infiltration of the gas phase under vacuum The carbon and decarburization effects are greatly reduced, and it is ea...

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Abstract

The invention relates to a production process for a large-sized hard alloy valve ball with the diameter larger than 80mm. The production process comprises the steps that a mixture is prepared according to proportions required by a formula; the mixture is poured into an upper half ball mold and a lower half ball mold to assemble a ball mold, the ball mold is sealed and sent into a static pressure machine, an initial shape of the ball valve is formed in a compressing mode, and compression molding is performed for multiple times by adjusting compression angles of the ball mold; the vacuum sintering technology is adopted for sintering of the valve ball formed in the compression mode; forcing refiring is conducted in a pressure sintering furnace; a finished ball product is made by grinding on a grinding machine; and parameters of the finished ball product are detected, if qualified, the machining is completed and if not, sub-quality products are crushed for recovery treatment. Different formulas are made according to different requirements to produce the mixture; the multi-time forming mode is adopted for producing rough balls with the compression defect in the prior art effectively overcome; the unique sintering technology is adopted and no crack forms; and the finished ball product can achieve + / -3 micrometers in size precision, the ovality is smaller than 1 micrometer, and the roughness is smaller than or equal to Ra0.01.

Description

technical field [0001] The invention belongs to the technical field of hard alloy manufacturing, and in particular relates to a production process of hard alloy valve balls. Background technique [0002] Cemented carbide refers to an alloy material made of hard compounds of refractory metals and bonding metals through powder metallurgy. Cemented carbide valve is an important high-hardness material for surface materials and surface technology. It is combined with the base material by surfacing welding to meet the functional requirements of wear resistance and corrosion resistance, and to extend the service life of equipment and workpieces. At present, the common cemented carbide refers to the main components such as tungsten carbide (WC), cobalt (Co) and titanium alloy (Ti), which has good wear resistance and corrosion resistance while having high hardness. [0003] At present, powder metallurgy technology is widely used at home and abroad to produce cemented carbide valve b...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B22F3/16B22F5/10C22C29/08C22C29/10
CPCB22F3/16B22F5/10C22C29/005C22C29/067C22C29/08C22C29/10
Inventor 李梁
Owner 四川欧曼机械有限公司