Learn about the weather resistance, adhesion of common coatings, and the requirements for rust removal on steel surfaces
Thread Content
Weather resistance, adhesion of commonly used coatings, and requirements for rust removal on steel surfaces. Types of coatings, requirements for weather resistance and adhesion, and rust removal levels: Used for severe corrosion, moderate corrosion, or mild corrosion. Phenolic resin coatings: generally good; Sa2.5, St3, St3. Asphalt coatings: poor; generally Sa2 or St3, St3, St3. Alkyd resin coatings: very good; Sa2.5, St3, St3. Vinyl chloride coatings: good to poor; Sa2.5, Sa2.5 – not used. Epoxy resin coatings: poor to good; Sa2.5, Sa2.5 – not used. Polyurethane coatings: very good; Sa2.5, Sa2.5 – not needed. Silicone heat-resistant coatings: good; generally not used; Sa2.5, Sa2.5. Chlorosulfonated polyethylene coatings: good; generally Sa2.5, Sa2.5, Sa2.5. Chlorinated rubber coatings: good; generally Sa2.5, Sa2.5, Sa2.5. Inorganic zinc-rich coatings: very good; Sa2.5, Sa2.5 – not used. Coatings specifically designed for water coolers: poor to good; Sa2.5, Sa2.5 – not used. Antistatic coatings for oil tanks: poor to good; Sa2.5, Sa2.5 – not used. Note: For primers used as anti-corrosion coatings, those with strong adhesion should be chosen; for topcoats used outdoors, coatings with good weather resistance should be selected. For newly constructed anti-corrosion projects, rust removal must be carried out in accordance with this table and the design requirements. To ensure the quality of corrosion protection, the final approval of the anti-corrosion coating must be given by the Mechanical Department. In maintenance and repair work, if the rust removal level cannot meet the standard requirements, it must be approved by the competent authority, and necessary tests must be conducted before the rust removal level can be reduced.
The requirements for the weather resistance, adhesion of coatings, and rust removal on steel surfaces are as follows: 1. Phenolic resin coatings: Suitable for moderately corrosive environments; they have average weather resistance but good adhesion. The steel surface must be rust-free to a Sa2.5 level. 2. Asphalt coating: Suitable for mildly corrosive environments; it has poor weather resistance and average adhesion, with a rust removal grade of Sa2 or St3 required. 3. Alkyd resin coatings: Suitable for various corrosive environments, with good weather resistance and adhesion; the steel surface must be rust-removed to Sa2.5 standard. 4. Perchloroethylene coatings: Suitable for highly corrosive environments; they have good weather resistance but poor adhesion, and are not suitable for less corrosive environments. The steel surface is required to be rust-removed to Sa2.5 standard. 5. Epoxy resin coating: Suitable for highly corrosive environments; it has poor weather resistance but good adhesion. It is not suitable for less corrosive environments, and rust removal to Sa2.5 grade is required. 6. Polyurethane coatings: Suitable for various corrosive environments, with good weather resistance and adhesion; the steel surface requires rust removal to Sa2.5 grade. 7. Silicone heat-resistant coating: Suitable for moderately corrosive environments, with good weather resistance; adhesion is average, and strict rust removal requirements on the steel surface are not necessary. 8. Chlorosulfonated polyethylene, chlorinated rubber: Suitable for highly corrosive environments; good weather resistance; moderate adhesion; the steel surface requires rust removal to Sa2.5 grade. 9. Inorganic zinc-rich coatings, coatings specifically for water coolers, and antistatic coatings for oil tanks: These are mainly suitable for special environments; they offer good weather resistance and adhesion, and the steel surface is required to be rust-free to a Sa2.5 level. To ensure the quality of corrosion protection, the selection of anti-corrosion coatings and the rust removal level must be carried out in accordance with the design requirements. .