| 等级 | 项 目 | 24h | 48h | 72h | 96h |
| Ⅱ | 腐蚀率(%) | 0% | ＞0%≤0.1% | ＞0.1%≤0.25% | ＞0.25%≤0.5% |
| 外观缺陷 | 无 | 无 | 轻微 | 中等 | |
| Ⅲ | 腐蚀率(%) | 0% | ＞0.1%≤0.25% | ＞0.5%≤1.0% | ＞1.0%≤5% |
| 外观缺陷 | 无 | 轻微 | 轻微 | 中等 | |
| Ⅳ | 腐蚀率(%) | 0% | ＞0.5%≤2.5% | ＞5%≤10% | ＞10%≤25% |
| 外观缺陷 | 无 | 轻微 | 中等 | 严重 | |
| Ⅴ | 腐蚀率(%) | 0% | ＞5%≤10% | ＞10%≤25% | ＞30%≤75% |
| 外观缺陷 | 无 | 中等 | 严重 | 严重 |
