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.

The rust level for steel product surface

There are 4 levels for the rust of steel product surface
1. covered by large area oxidation layer nearly without rust.
2. rust has occurred and oxidation layer starts falling.

3. oxidation layer has rusted and fell, or rust layer can be scraped, but steel surface, which has some rust spots, can be observed with the naked eye.

4. oxidation layer has rusted and fell, or rust layer can be scraped, but steel surface, which has a lot of rust spots, can be observed with the naked eye.

Coating for the blasted steel

Shipbuilding steel generally needs coating with shop primer, which has 4 types as follows:

1. Wash primer.
2. Zinc Epoxy Primer.
3. Non Zinc Epoxy Primer or Epoxy Primer.
4. Inorganic Zinc Silicate Primer.

The type and thickness of coating should be according to customers' requirements. There is some world-famous brands, like AkzoNobel, Hempel.and Jotun.