The hardness grade of grinding wheel is an important indicator to measure the difficulty of grinding wheel abrasive grains falling off under external force. The choice of hardness grade directly affects the grinding performance of grinding wheel and the processing effect of workpiece. The following is a detailed description of the hardness grade of grinding wheel:
1. Classification of hardness grade
The hardness grade of grinding wheel is usually divided into seven grades, including super soft, soft, medium soft, medium, medium hard, hard and super hard. Each grade can also be subdivided into several grades, such as soft 1, soft 2, soft 3, etc., a total of 14 grades.
2. Codes for hardness grades
The hardness grades correspond to the codes as follows:
Super soft: A, B, C, D, E, F
Soft: G (soft 1), H (soft 2), J (soft 3)
Medium soft: K (medium soft 1), L (medium soft 2)
Medium: M (medium 1), N (medium 2)
Medium hard: P (medium hard 1), Q (medium hard 2), R (medium hard 3)
Hard: S (hard 1), T (hard 2)
Super hard: Y.
3. Selection principles for hardness grades
The selection of hardness grades should be based on the processing materials and process requirements:
Processing soft materials: Use hard grinding wheels to prevent abrasive grains from falling off prematurely.
Processing hard materials: Use soft grinding wheels to promote the timely shedding of abrasive grains and maintain the self-sharpening of the grinding wheel.
Fine grinding: Use slightly harder grinding wheels to ensure processing accuracy and surface finish.
Materials with poor thermal conductivity or easy to burn: Choose a softer grinding wheel to reduce the risk of cracks and burns.
4. Relationship between hardness and binder
The hardness of the grinding wheel depends not only on the abrasive, but also on the performance, quantity and manufacturing process of the binder. For example, a grinding wheel with a resin bond is usually 1-2 grades harder than a grinding wheel with a vitrified bond.
5. Hardness and grinding performance
The hardness of the grinding wheel directly affects its self-sharpening. The abrasive grains of a hard grinding wheel are not easy to fall off, which is suitable for long-term stable grinding; the abrasive grains of a soft grinding wheel are easy to fall off, which is suitable for rapid renewal of abrasive grains and keeping them sharp.
By reasonably selecting the hardness grade of the grinding wheel, the grinding effect can be optimized and the processing efficiency and quality can be improved. If you need to know more about other characteristics of the grinding wheel (such as abrasives, binders, etc.), please refer to relevant technical information.
