What is the role of silicon carbide added to the aluminum alloy solution

1. the performance of aluminum alloy: in non-ferrous metal materials, aluminum alloy is the use of more common materials. Its grinding processing, mechanical, physical properties are different from steel and cast iron and other metal materials, it has the following characteristics:

Low hardness and strength: The highest hardness of aluminum alloy is HB110 ~ 120, and the maximum tensile strength is generally 20~30kg/cm2. Due to the low hardness, the material has poor ability to resist plastic deformation or scratches, and it is easy to scratch and bump the surface of the workpiece during grinding.

2, plastic ductility, plastic adhesion in the grinding process, blocking the surface of the grinding wheel; at the same time, the melting point of aluminum alloy is low (660~780 ℃), in the high temperature of the grinding zone, the surface of the metal melting, adhesion grinding wheel surface, resulting in hot melt adhesion and increased the blocking of the grinding wheel.

3. Large linear expansion coefficient: Under the action of grinding heat, it is easy to cause deformation of the aluminum alloy workpiece, which affects the grinding accuracy of the workpiece surface.

Low grinding efficiency: In order to overcome the thermal deformation of aluminum alloy workpieces in grinding, reduce the adhesion of the grinding wheel surface, and ensure the quality of the processed surface, the number of dressing must be increased, which is about 3 times that of ordinary steel, thus reducing The grinding productivity.

The choice of aluminum alloy grinding wheel for 2. grinding: the biggest problem in the process of aluminum alloy grinding is "sticking" and "blocking"

A, aluminum alloy ultra-precision grinding, mirror grinding: the use of "PVA" grinding wheel, equivalent to the Japanese "UB" grinding wheel. The mirror effect can be achieved. This grinding wheel is also similar in structure to the ceramic grinding wheel (see below).

B, aluminum alloy rough grinding and semi-fine grinding:

1, abrasive: the use of brittle and sharp black silicon carbide.

2, bonding agent: the use of high strength ceramic bonding agent, and oil resistance, acid resistance, alkali resistance, corrosion resistance.

3, granularity: in the case of meeting the requirements of the use of coarse number. Rough grinding: 36~46#; Fine grinding: 60-80; Coarse size number is relatively small in the number of abrasive particles to participate in grinding, grinding heat is also less, reduce the deformation of the workpiece and grinding wheel blockage;

4, hardness: should choose a lower hardness, so that the grinding wheel to maintain a good self-sharpening. Generally choose H ~ J hardness.

5. Organization: Loose organization should be used to accommodate the wear debris, so that the coolant enters the grinding zone, enhances the cooling effect, and reduces the temperature of the grinding zone. Should choose loose tissue of the large hole grinding wheel, has a better grinding effect.

3. grinding fluid:

The use of good cleaning performance, good lubrication performance, cooling performance of the grinding fluid. And the grinding fluid supply should be sufficient to ensure that it has a good cleaning and cooling effect. It is recommended to use the special grinding fluid for aluminum grinding produced by the manufacturer, such as the ALUSOL series of Castrol. If the conditions do not allow the use of diesel as grinding fluid, the practical effect is also ideal. But the use of diesel oil in the process of easy to produce oil mist, and volatile. In view of this: a small amount of oil or carbon tetrachloride can be added to diesel.

4. grinding skills:

The feed speed should be uniform during the grinding process, especially the transverse feed.

2. The grinding wheel is easy to be blocked and passivated in the grinding process of aluminum, so the surface of the grinding wheel is easy to be scratched and burned. Therefore, the surface of the grinding wheel needs to be lubricated when machining: external coating lubricating fluid, oil and paste can be appropriately increased. The grinding wheel can be painted with diesel oil, but it is dirty. It can be coated with candles, industrial waxes, lubricants, lubricating pastes, etc. Can reduce the blockage caused by burns, scratches, etc.

3, the aluminum chips on the grinding wheel, you can use the oil stone or use a good blade. Scrape the sticky chips.

4. The grinding wheel must be trimmed in time, and the trimming should be rough, but it must be sharp to prevent blockage.

5, grinding wheel corner can use grinding wheel knife down corner. To facilitate the timely discharge of aluminum chips.