A grinding wheel consists of grains,bond and pores,and the grain (cutting edge) grinds a workpiece while being worn,crumbling,and being released to leave a new cutting edge over and over again.The factors which determine the performance of grinding wheels are the grain type,grit size,bond type,hardness,and structure. In order to carry out the grinding work requiring high performance,a highly finished surface and accuracy,the above five factors must be properly taken into consideration. Five factors which control the performance of grinding wheels: (1) Grain Type (2) Grit Size (3) Bond Type (4) Hardness (5) Structure |
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Grain Type:
The abrasive grains are the main materials for making abrasive tools and perform grinding,cutting and polishing activity in the grinding process. The abrasives for common abrasive tools is grouped into aluminum oxide type and silicon carbide type,which also are further classified.Since each type abrasive grains have its own characteristics,it is very important to know the features and select the most suitable type for the grinding process.
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Code
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Type
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Features
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Usage
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A
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Brown fused alumina
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High hardness and toughness
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It is suitable for grinding medium and high tensile strength metal such as ordinary carbon Steel,alloy steel,malleable cast iron,hrad bronze,etc.
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WA
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White fused alumina
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Its hardness is higher than that of A.Its grains are easily broken.The edges of the grains are sharp and of excellent cutting performance..Only samall quantity of heat is created in use.
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It is used for grinding harder material and metals sensitive to heat such as chilled steel,high carbon steel,ordinary high speed steel,alloy steel.It is mainly suitabl for the grinding and forming grinding of instruments,cutting tools,mouldings,gears,threads,thin-wall parts,etc.
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PA
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Pink fused alumina
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Its hardness is close to WA,but toughness higher than that of WA.The edges of its grains are sharp and can be kept well.It is also excellent durability.
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It is suitable for the grinding of chilled steel,cutting tools and workpieces of alloy steel as well as the precision grinding of measuring tools and parts of instruments and apparatus,etc.
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SA
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Monocrystalline fused alumina
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Its hardness is higher than that of A and WA.It grains are ball-shaped single crystals with outstanding multi-corner edges and strong impact strength,etc.
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It is suitable for the grinding of stainless steel,high vanadium-high speed steel and the workpieces in high toughness and being easily-deformed and burnt.
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MA
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Microcrystalline fused alumina
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Its grains are composed of small crystals in high toughness and strong strength and of excellent self-sharpening performance.
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It is suitable for the grinding of ball-bearings,stainless steel and special nodular cast iron as well as forming grinding,in feeding grinding and other precision grinding,etc.
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A/WA
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Mixture of A and WA
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It posseses the advantages of both A and WA
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It is suitable for the grinding of nodular cast iron crankshaft,camshaft and other workpieces.
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GC
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Green silicon carbide
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It is in high hardness and brittle.Its grain edges are sharp and it is of excellent capacity of heat-transmission.
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It is suitable for the grinding of cutting tools and workpieces of hard alloy,and non-ferrous metal and non-metal materials,etc.
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C
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Black silicon carbide
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It is in high hardness and brittle.Its grain edges are sharp and it is of a certain capacity of heat-transmission.
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It is suitable for the grinding of non-ferrous and non-metal materials.
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