Process Requirements For Paint Coating Of Crane Transportation Machinery
Dec 24, 2023
Process requirements for paint coating of crane transportation machinery
Surface Treatment
1. If there is moisture, oil, or dust on the metal surface before rust removal, compressed air or washing solvent should be used to dry it or degrease it.
2. Remove rust, oxide scale, sludge, welding slag, spatter, etc. (it is allowed to manually remove a small amount of residual oxide scale in places that are difficult to remove during shot blasting).
3. The metal surface after rust removal should be carefully blown with compressed air.
4. Steel structural parts exposed to the air should be sand blasted or shot blasted for surface rust removal before painting (for plates with a thickness less than 6mm, spray cleaning, manual and power tool rust removal are easy to deform, and pickling should be used to remove rust. rust method), the surface pretreatment before painting complies with the Sa21/2 level of the GB/T 8923.1-2011 standard, and other parts reach the St2 level. After rust removal, the surface roughness reaches 40~80μm.
5. After the rust removal work is completed, clean the metal surface and apply anti-rust primer in time. to
Preparation Before Painting
1. The construction site should maintain good and safe access, good lighting and ventilation to facilitate surface treatment and painting construction, as well as quality inspection.
2. Clean all parts of the 30 ton crane before painting, and take protective measures according to the characteristics of the equipment components (unpainted parts: nameplate, machined mating surface, cylindrical surface of the brake wheel, toothed part of the gear, should be Apply grease or wrap with plastic sheeting before painting).
3. The metal surface coated with primer must be dry, and there must be no moisture, dew, frost, or moisture layer.
Painting Steps
1. Primer application should be carried out in a clean and dry place. The minimum ambient temperature should not be lower than 5℃, and the relative humidity should be lower than 80~85%. When applying outdoors, it is prohibited to apply in the scorching sun, rain, fog, and sand. Spray (brush) paint.
2. Apply primer once according to the technical requirements of the product. If the product needs to be coated twice with primer, it must be done after the first primer is dry. The general drying time is 24~48 hours when the temperature is 18℃~23℃.
3. The topcoat must be completely dry after the primer is applied (drying time is 24~48 hours when 18℃~23℃) before construction. to
4. Before applying the topcoat, the oil and dust on the surface of the primer must be removed to make the surface clean (it should be dried at 18℃~23℃ for 0.2~0.3 hours after degreasing) and there must be no moisture, dew, frost and moisture layer.
5. The topcoat should be applied when the relative humidity is 40~70% and the temperature is 12℃~25℃. When constructing outdoors, it is prohibited to brush or spray paint in the scorching sun or windy sand.
6. If a second coat of surface paint is required, the second coat of topcoat must be sprayed after the first coat of topcoat is dry (drying time is 24 hours when 18℃~23℃)
General Technical Requirements for Painting
1. The primer applied to the metal surface should have good adhesion and corrosion resistance.
2. Two methods of brushing and spraying are allowed. When spraying, the spraying equipment and pressure should meet the requirements of the product instructions to ensure that the paint film is uniform, flat and smooth.
3. The paint surface of the product must be firm, flat, smooth, and uniform in color. The appearance of the paint film is not allowed to have sagging, peeling, or obvious orange peel. A comprehensive inspection should be carried out before packaging. The adhesion of the paint film complies with GB/T 9286- Level 1 requirements in the 1998 standards.
4. After surface treatment, the correct paint should be applied to the surface to be painted within 4 hours.
5. The paint surface must have a uniform paint film, no exposed bottom, no pinholes, no wrinkles, no leaks, no cracks, etc. The surface must be seriously sagging.
6. Dry film thickness of paint: The paint film should reach the specified film thickness. The paint color of the equipment shall be as specified in the technical agreement. Repair the defective parts to eliminate scars and other defects.
7. Strictly adjust the paint characteristics and proportions and carry out painting operations in accordance with its mature process requirements.
Make the following comments about the grade codes described in the text:
Level Sa2 1/2: Very thorough blast cleaning. When viewed without magnification, the surface should be free of visible oil, grease and dirt, and free of scale, rust, coatings and foreign impurities. Any remaining traces of contamination will appear only as slight spots or streaks of color.
Level St2: Thorough cleaning of hand and power tools. When observed without magnification, the surface should be free of visible oil, grease and dirt, and free of loose scale, rust, coatings and foreign impurities.
