Grain Size Definition
| Definition | Range of Average Grain Size? | Typical Metallurgraphic Picture （1500X) |
| Ultrafine | 0.3～<0.6 ?m |  |
| Submicron | 0.7～<0.8 ?m |  |
| Fine | 0.8～<1.0 ?m |  |
| Medium- | 1.1～<1.6 ?m |  |
| Medium | 1.6～<2.5 ?m |  |
| Coarse | 2.5～6.0 ?m |  |
| Extra Coarse | >6.0 ?m |  |
