The ASTM B695 specification covers the requirements for a coating of zinc mechanically deposited on iron and steel basis metals. The coating is provided in several thicknesses up to and including 107μm. The seven thickest classes are usually referred to as “mechanically galvanized”.
B695 Coating Classifications
| Class | Minimum Thickness, μm |
|---|---|
| 110 | 107 |
| 80 | 81 |
| 70 | 69 |
| 65 | 66 |
| 55 | 53 |
| 50 | 50 |
| 40 | 40 |
| 25 | 25 |
| 12 | 12 |
| 8 | 8 |
| 5 | 5 |
| Class 55 is the most common class used for ASTM fasteners and is roughly the same thickness as hot dip galvanizing per ASTM F2329. 53μm is equivalent to 0.002087 inches or 2.087 mils. | |
B695 Types
| Type | Description |
|---|---|
| I | As coated, without supplementary treatment |
| II | With colored chromate conversion treatment |