Carbide vacuum sintering process

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The manufacture of vacuum sintered carbide inserts is a carefully designed process, with geometries and grades balanced to provide a product perfectly matched to the application.
Vacuum sintering powder production
There are two main elements in vacuum sintered carbide inserts: tungsten carbide (WC) and cobalt (Co). Other commonly used elements are titanium carbide, tantalum carbide and niobium carbide. Different types of powders and different percentages of elements can be designed to form different materials. The powder is milled, spray dried, sieved and poured into containers.

Tungsten powder
Tungsten carbide grain size. The main raw material used to manufacture vacuum sintered cemented carbide is tungsten concentrate. Tungsten powder is manufactured from tungsten oxide derived from this raw material through a chemical reaction. By changing the reduction conditions, tungsten powders of various particle sizes can be produced. The cemented carbide particles after spray drying are smaller and vary in size depending on the material.

Basic characteristics of vacuum sintered cemented carbide
In addition to the grain size of tungsten carbide (WC), the content of the binder phase is also an important factor in determining the characteristics of the cemented carbide. At the same time, increasing the cobalt content and increasing the WC grain will help to improve the toughness, but it will also reduce the hardness, thereby reducing the wear resistance of the matrix.

Powder pressing

The pressing work requires the use of several tools: top and bottom punches, center pin cavity.

Pressing steps
Pour the powder into the cavity,
Top and bottom punch engagement (20-50 tons),
Blades are picked by a robot and placed on graphite trays,
Perform a random SPC to check the weight.
At this stage, the blade is 50% loose and permeable.

Vacuum sintered pressed blades
Place the blade tray into the vacuum sintering furnace.
Increase the temperature to about 1400°C (about 2550°F).
The process will melt the cobalt, which acts as a binder.
During the vacuum sintering stage, the insert will shrink by 18% in all directions, which corresponds to a volume reduction of approximately 50%.

1.Non-vacuum sintered blade

2.Vacuum sintered blade

3.Coated blade

Vacuum sintering equipment selection: The vacuum sintering furnace produced by SIMUWU company is reliable in quality and trustworthy. RVS vacuum degreasing sintering furnace is used for degreasing and sintering of bast stainless steel, hard alloy, high temperature alloy, high specific gravity alloy, cermet, etc. Two production processes of continuous and sintering can be realized in the same furnace. Degreasing and sintering furnaces are used to avoid repeated product displacement, heating and cooling, improve product quality, shorten production cycle and improve production efficiency.

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