Process flow of paint for steel

Wed May 25 2022 JITAI

Base treatment → apply anti-rust paint → scrape putty → apply phosphating primer → paint paint for steel

1. Basic treatment
First remove the floating soil, sand, mortar, oil stains, rust spots, welding slag, burrs, etc. on the metal surface. Then carry out surface rust removal, and the method can be handled by hand. If the metal surface is general floating rust, you can first use a wire brush to reciprocate, then use a coarse emery cloth to polish a new bright surface, and then use an old cloth or cotton yarn to clean the floating ash and rust; If the surface rust is more serious (scaly rust spots), first use a spatula to shovel off the rust scale, or use a hammer or scraper to clean it, then use a wire brush to clean it, and then polish it with an emery cloth until it becomes bright, and then the anti-rust paint can be applied. For large areas of rust, first use a grinder, wind mill and other electric rust removal tools to remove rust, and then use tools such as wire brushes, files, steel shovels and emery cloths to remove remaining rust and debris by brushing, filing and grinding.
2. Apply anti-rust paint
When applying Hongdan anti-rust paint, the surface of the component must be dry, and if there is water droplets or moisture, it must be wiped dry. When applying, be sure to brush in place, fully and evenly. For small steel structural components or metal products with complex patterns, two people can work together, one person can use cotton yarn dipped in paint to wipe it; For the gaps in the steel components that are not easy to be painted (such as the angle steel backs of the angle steel composite components), the rust removal and painting processes at the joint gaps should be completed before assembly, but the rivet holes should not be painted. In order to avoid slag inclusions in the nail holes after riveting.
3. Scrape putty
After the anti-rust paint is dry, buy the putty matched with the paint to smooth the surface defects of the components. An appropriate amount of thick paint or red powder can be added to the putty to increase its dryness. After the putty is dry, it should be smoothed and cleaned. After the steel structure components are made in the factory, they should be pre-painted with anti-rust paint. After being transported to the construction site, if the stacking time is long, some parts have peeled off and rusted, and the anti-rust paint should be painted again.
4. Apply phosphating primer
In order to make the paint on the metal surface have better adhesion, prolong the service life of the paint, and avoid rust and corrosion, a layer of phosphating primer can be applied on the surface of the steel structural member. The phosphating primer consists of two parts, one is the primer and the other is the phosphating solution. When painting, it is advisable to use thin layers, but not too thick, which will cause peeling and poor adhesion. The thick paint can be diluted with a mixture of three parts ethanol (above 95%) and one part butanol. The water content of ethanol and butanol should not be too large, otherwise the lacquer wax will easily whiten and affect the effect. After the phosphating primer is painted for 2 hours, other primers or topcoats can be painted. Under normal circumstances, after 24 hours of painting, you can rinse with water and use a brush to remove the phosphating residue on the surface. After drying, make an appearance inspection. If a gray-brown uniform phosphating film is formed on the metal surface, the requirements of phosphating are met.
5. Apply paint for steel
After the surface of the steel structure components is polished flat and cleaned, the paint for steel can be painted. Brushing order: from top to bottom, first difficult and then easy. When painting paint for steel, it is necessary to brush more and more rationally, and the oil should be full, not runny, even bright, and consistent in color. After brushing, check repeatedly to avoid missing brushing, and the steel structure topcoat is generally brushed twice to survive.

Process flow of paint for steel