powder

Tungsten oxide is mixed with carbon and processed in a special furnace to form tungsten carbide, the main raw material of all cemented carbides. Tungsten carbide, an extremely hard and brittle material, is used as the main component of cemented carbides. Tungsten carbide is mixed with cobalt, which is essential for the properties of cemented carbide. The more cobalt, the better the toughness of cemented carbide; On the contrary, the more hard, wear-resistant. The weight ratio of different components is carried out with the highest precision. The error of a batch of 420 kg raw material should not be greater than 20 grams. Mixing is a delicate metallurgical operation. Finally, the mixture is ground into a fine and delicate powder in a large ball mill. The mixture must be spray dried to obtain correct fluidity. After grinding, the granularity of the powder reaches Ø 0.5-2.0um.

To suppress

The basic shape and dimensions are obtained by pressing with a punch and die in a highly automated CNC controlled press. After pressing, the blade looks very similar to a real carbide blade, but the hardness is far from perfect.

The sintering

To harden, the blade is heat treated at 1500 ° C for 15 hours. The molten cobalt is bonded to the WC particles through a sintering process. The sintering furnace process does two things: the blade shrinks significantly, and the shrinks must be accurate to get the right tolerance; Second, the powder mixture is transformed into a new material with metallic properties, called cemented carbide. The blades are now as hard as expected, but not ready for delivery. Before proceeding to the next step of production, we will carefully check the dimensions of the blade in the CMM.

grinding

Only through diamond grinding can the carbide blade have an accurate shape. The blade can be grinding according to the requirement of geometric Angle. Most grinders have built-in measurement controls that check and measure the blades in several stages.

Edge processing

The cutting edges are treated to obtain the correct shape to achieve the maximum wear resistance required for machining. These blades can be brushed with a special brush with a silicon carbide coating, and the final result must be checked regardless of the processing method used. 90% to 95% of all blades have some kind of coating. Make sure there are no foreign particles on the blade surface to prevent these particles from sticking under the coating and affecting tool performance.

coating

Chemical Vapor Deposition (CVD) and Physical Vapor Deposition (PVD) are two existing coating methods, and the choice of the method depends on the material and processing method. Coating thickness depends on blade application. Coating determines blade durability and blade life. The technical know-how is that the surface of cemented carbide is coated with many very thin coatings, such as titanium carbide, aluminum oxide and titanium nitride, which can greatly increase the service life and durability.

If the CVD method is used to coat the blades, the blades are placed in a furnace and chlorides and oxides in the form of gases are added along with methane and hydrogen. These gases interact with each other at 1000 ° C and also act on the cemented carbide surface, giving the blades a homogeneous coating only a few thousandths of a millimeter thick. Some coated blades gain a golden surface, become more valuable and last up to five times as long as uncoated blades. PVD is applied to the blade at 400 degrees Celsius.