Steel surface treatment

Usually, there are 3 ways for steel surface treatment.

1. Spray treatment, Sa. which generally can be divided into four levels:
 Sa1: mild spray treatment.
 Sa2: thorough spray treatment.
 Sa2.5: very thorough spray treatment.
 Sa3:  making the surface clean spray treatment.
Shipbuilding steel product requires Sa2.5 level.

2. Hand and power tool cleaning, St
 St2: thorough hand and power tool cleaning
 St3: very thorough hand and power tool cleaning

3. flame treatment, F1
 After flame treatment, the surface should be cleaned by power wire brush, but it can't be up to the grade of coating.