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Vacuum Heat Treatment Furnace

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What is the vacuum sintering method

Vacuum sintering is a special heat treatment process. Its purpose is to turn porous powder compacts into alloys with certain structures and properties. Sintering is the last step in the production process of cemented carbide. The structure and properties of the alloy are of course It depends on many process factors before sintering, but under certain conditions, the sintering process has a significant or even decisive impact on it.

The sintering of cemented carbide is a multi-element system of liquid phase sintering. The process is relatively complex, involving both physical and chemical changes, but the main ones are physical changes, including densification of the sintered body, growth of carbide grains, and adhesion. Changes in phase composition and structure and the formation of alloy structures, etc.
For vacuum sintering to be effective, the powder particles must be in close contact with each other. Therefore, sintering is usually applied to pressed or molded powders rather than loose powders. While most powder parts are sintered during the manufacturing process, in this case sintering is primarily used to achieve a metallurgical bond between particles. This is often the case with mold parts, where dimensional control is extremely important.
The cemented carbide vacuum sintering process is a high-tech profession that requires knowledge and skills in the properties, composition, preparation process, sintering equipment, and sintering parameters of cemented carbide. The work content of cemented carbide vacuum sintering is to process cemented carbide powder through pressing, pre-sintering, vacuum sintering and other processes to make cemented carbide products of various shapes and specifications, such as cutting tools, molds, drill bits, etc.

The preparation process of cemented carbide mainly includes the following steps:
Powder preparation: Mix different proportions of hard phase and bonding phase according to a certain formula, and perform ball milling or spray drying to form a uniform fine powder.
Press molding: Put the powder into a mold and form it into a blank of the required shape and size through high pressure or isostatic pressing.
Pre-burning treatment: Put the billet into the furnace and control it under a certain temperature and time to remove impurities and residual substances in the powder, while increasing the strength and density of the billet.
Vacuum sintering treatment: Put the pre-sintered billet into a furnace with a protective atmosphere such as vacuum or hydrogen, and control it at a higher temperature and for a longer time to cause solid phase or liquid phase sintering, thereby forming a shape with final properties Carbide products.
Post-processing: As needed, the sintered cemented carbide products are subjected to machining, surface treatment, testing and other processes to meet different usage requirements.
Vacuum sintering furnace: A vacuum pump is used to extract the air in the furnace to form a vacuum environment, so that the blank can be sintered in solid phase or liquid phase at high temperature. Vacuum sintering furnace has the advantages of energy saving, environmental protection, safety and controllability, and is currently the most widely used cemented carbide sintering equipment.