Grinding wheel hardness classification and code:
Code: A B C D E F hardness and other level: super soft (large, small)
Code: G Hardness level: Soft 1
Code: H Hardness level: Soft 2
Code: J Hardness level: Soft 3
Code: K Hardness level: Medium soft 1
Code: L Hardness level: Medium soft 2
Code: M Hardness level: Medium 1
Code: N Hardness level: Medium 2
Code: P Hardness Grade: Medium Hard 1
Code: Q Hardness Level: Medium Hard 2
Code: R Hardness Level: Medium Hard 3
Code: S Hardness level: Hard 1
Code: T Hardness level: Hard 2
Code: Y Hardness level: Super hard
There are many kinds of grinding wheels. According to the abrasives used, it can be divided into ordinary abrasives (corundum and silicon carbide, etc.) grinding wheels and natural abrasive super-hard abrasives and (diamond and cubic boron nitride, etc.) grinding wheels; according to the shape, it can be divided into flat grinding wheels, beveled grinding wheels, cylindrical grinding wheels, Cup-shaped grinding wheels, dish-shaped grinding wheels, etc.; according to the bond can be divided into ceramic grinding wheels, resin grinding wheels, rubber grinding wheels, metal grinding wheels, etc.
The characteristic parameters of the grinding wheel mainly include abrasive, particle size, hardness, bonding agent, shape, size and so on. Since the grinding wheel usually works at high speed, it is necessary to carry out a rotation test (to ensure that the grinding wheel will not break at the working speed) and a static balance test (to prevent vibration of the machine tool during work) before use. After working for a period of time, the grinding wheel should be trimmed to restore the grinding performance and correct geometry.
The hardness of the grinding wheel and the hardness of the abrasive are two different concepts. The same abrasive can be made into abrasive wheel with different hardnesses, which is mainly determined by the performance and quantity of the bond and the manufacturing process of the abrasive wheel. The significant difference between grinding and cutting is that the grinding wheel has “self-sharpening”. Choosing the hardness of the abrasive wheel is actually choosing the self-sharpening of the abrasive wheel. It is hoped that the sharp abrasive particles will not fall off too early, nor should they not fall off after being dull. .
The general principle of choosing the hardness of the abrasive wheel is: when processing soft metals, in order to prevent the abrasive from falling off prematurely, use a hard abrasive wheel. When processing hard metals, in order to make the blunt abrasive particles fall off in time, thereby exposing new abrasive particles with sharp edges and corners (ie, self-sharpening), soft abrasive wheel are used.
The former is because when grinding soft materials, the abrasive wear of the abrasive wheel is very slow and does not need to be detached too early; the latter is because when grinding hard materials, the abrasive wear of the abrasive wheel is faster and requires faster Update. In order to ensure the precision and roughness of grinding, a slightly harder abrasive wheel should be used for fine grinding. When the workpiece material has poor thermal conductivity and is prone to burns and cracks (such as grinding cemented carbide, etc.), the selected abrasive wheel should be softer.