Aluminum Oxide is an abrasive consisting of blunt shaped grain and is very tough in its lowest refined form. It is produced in a variety of refinements and by its versatility can be used from very hard to soft applications, making it the most commonly used abrasive.
Silicon Carbide is an abrasive that is hard, and sharp with exceptional strength, but due to its brittleness it breaks down faster than aluminum oxide under heavy loads.
Ceramic Grain abrasive is non-fused ceramic aluminum oxide that is extremely tough in all grades. It provides exceptional durability and cut rates. This grain is more costly, so its merits need to be evaluated against the common aluminum oxides.
MINERAL TYPES_________________
Friable abrasive grain is easily fractured by impact, therefore, constantly exposing fresh cutting crystals to the work piece making it the fastest cutting abrasive.
Semi-friable abrasive grain does not fracture as readily as friable grain, therefore, gives longer life in comparison during the grinding process, but does not cut quite as freely as the friable grain.
ABRASIVE TYPES_________________
A-Aluminum oxide is very tough and is most generally used in resin bond applications.
27A-Aluminum oxide is semi-friable and of average hardness. It is the most widely used medium density fused aluminum oxide. It is produced in a complete range of grit sizes for use in general purpose vitrified applications.
6A-Aluminum oxide is semi-friable, and of average hardness. It is the designation used for segments.
28A-Premium aluminum oxide is friable white grain which has an aggressive cool fast cutting action while holding form well. It is used in the grinding of heat sensitive alloys, taking advantage of its friability and cool cutting ability. This grain is also widely used in grinding of heat treated tool steels, high speed steels, and internal wheels.
9A-Premium aluminum oxide is friable white grain specially used in the production of our segments.
AMA-Aluminum oxide is a friable very aggressive grain for use on the smaller mounted points where a tough composition is needed.
23A-Aluminum oxide is an off white friable very aggressive grain, used in larger mounted point and wheel applications where a tougher application is indicated.
29A-Aluminum oxide is a pure fused abrasive, alloyed with chrome oxide making it pink in color. Although friable and cool cutting, it exhibits marked formholding characteristics. Applications will be found in precision, broad surface and tool room grinding on hard alloy steels.
5A-Aluminum oxide is the designation for the pink pure fused abrasive alloyed with chromium oxide, used in the manufacture of our segments. 36A-Aluminum oxide is a high chromium ruby-colored fused abrasive, free of titania. It is made by fusing high purity calcined alumina and chromium oxide. It is a friable abrasive, somewhat tougher than white, with corner-holding characteristics, which is needed for precision grinding. It is a premium priced grain as compared to 28A-white and 29A-pink, so the merits as compared to these types should be weighed.
C-Silicon carbide is a black, semi-friable medium density abrasive. It is produced in both resin and vitrified points and wheels for grinding hard or brittle materials, such as cast iron, ceramics, and glass: as well as low tensile strength, ductile non-ferrous metals. GC-Silicon carbide is a green in-color, friable, highly pure, medium density abrasive used in vitrified bonded points and wheels. It is most commonly used for grinding hard, brittle materials, such as cemented carbides, where fast cool cutting is desirable.
CG-Aluminum oxide is non-fused ceramic grain that is very tough, pure, and of uniform quality. Applications are in resin and vitrified points and wheels for high stock removal rates and long life. It performs especially well in precision grinding and fine finish applications, without excess heat generation. As it is a premium priced grain, its merits need to be weighed in comparison to the more common specifications, and is most commonly used in combination with other grains for best results. Note:11A is another designation used for CG grain. While not new to industry, is gaining in popularily, particularly as cost conscious businesses search for products with longer life, less dressing and faster material removal. Ceramic Grains can be mixed with conventional aluminum oxide grains in proportions ranging from 20% to 50%. A 30% blend offers the ideal balance of cost and performance.
GRAIN COMBINATIONS_________________
| Grain combinations used in various proportions to obtain desired results |
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| Abrasive grain comes in a wide variety of grain sizes. For rough grinding and heavy stock removal coarse grit sizes are used, while fine grit sizes are used for work where a finer finish or a desired shape is necessary. | |
| GRAIN SIZE SPECIFICATIONS | |
|---|---|
| 8 10 12 14 16 | Very Course-for very heavy duty grinding(snagging) |
| 20 24 30 36 46 | Coarse to heavy deburring and grinding |
| 54 60 80 90 100 120 | Medium -for medium deburring, the most common for mounted point use |
| 150 180 200 | Fine - for light deburring |
| 240 320 | Very fine - for delicate work requiring a very fine finish |
| 400 500 600 | Ulra fine - requring a super fine finish with little removal |