| Grain Usages and Types | ||||
| Usage | For vitrified wheels | For organic wheels | For coated abrasives | For refractory materials |
| Type | WA | WA-B | WA-P | WA-R |
| Physical Characteristics | |||||
| Item | Basic mineral | Crystal system | Crystal color |
Mohs
hardness |
Density |
| White aluminum oxide | α- A l 2 O 3 | Hexagonal | White | 9 | ≥ 3.90g/c m 3 |
| Item | Micro hardness |
Electrical
resistivity |
Grinding ability(compared with
diamond as one) |
Linear expansion
coefficient(when 900 ºC α• 10 -6 k -1 ) |
|
| White aluminium oxide | HV2200-2300 | 10 14 -10 16 Ω• cm | 0.12 | 8.3 | |
| Chemical Composition | |||
| GB/T 2479-2008 | |||
| Type | Grit | Chemical composition (%, by weight) | |
| A l 2 O 3 | Na 2 O | ||
| WA | F4-F80 | ≥ 99.10 | ≤ 0.35 |
| F90-F150 | ≥ 99.10 | ≤ 0.40 | |
| F180-F220 | ≥ 98.60 | ≤ 0.50 | |
| F230-F800 | ≥ 98.30 | ≤ 0.60 | |
| F1000-F1200 | ≥ 98.10 | ≤ 0.70 | |
| WA-B | F4-F80 | ≥ 99.00 | ≤ 0.50 |
| F90-F150 | ≥ 99.00 | ≤ 0.60 | |
| F180-F220 | ≥ 98.50 | ≤ 0.60 | |
| WA-P | P12-P80 | ≥ 99.10 |
≤
0.35
≤ 0.40 |
| P100-P150 | ≥ 99.10 | ||
| P180-P220 | ≥ 98.60 | ≤ 0.50 | |
| P240-P800 | ≥ 98.30 | ≤ 0.60 | |
| P1000-P1200 | ≥ 98.10 | ≤ 0.70 | |
| P1500-P2500 | ≥ 97.50 | ≤ 0.90 | |
| WA-R | 0-1mm | ≥ 99.00 | ≤ 0.50 |
| 1-3mm | ≥ 99.00 | ≤ 0.50 | |
| 3-5mm | ≥ 99.00 | ≤ 0.50 | |
| 5-8mm | ≥ 99.00 | ≤ 0.50 | |
| Chemical Composition | |||||
| GB/T 2479v-2008 | |||||
| Type | Grit Size | Bulk Density | Whiteness | Chemical composition (%, by weight) | |
| Al 2 O 3 | Na 2 O | ||||
| WA | F120-F220 | ≥1.80g/cm3 | ≥80% | ≥99.10 | ≤0.40 |