Material

1.1 The selection of anti-corrosion materials for building steel structure engineering should meet the design requirements. Anti-corrosion materials include primer, topcoat and thinner. The anti-corrosion primer for building steel structure engineering includes red lead oil-based anti-rust paint; the anti-corrosion top paint for building steel structure includes various colors of alkyd enamel and various colors of alkyd mixed paint.
1.2 Main equipment:
Recycling device, hose, spatula, hand wheel, emery cloth, wire brush, cotton thread, paint bucket, brush, etc.
1.3 Operating conditions:
1.3.1 The steel structure project has been checked and accepted before the anti-corrosion coating project, and meets the design requirements.
1.3.2 The anti-corrosion coating work site shall have safety protection measures, fire prevention and ventilation measures to prevent fire and personnel poisoning accidents.
1.3.3 Appropriate weather should be selected for open-air anti-corrosion construction operations, and operations should not be performed in strong wind, rain, or severe cold.


Operation process

2.1 Process flow:
Base surface cleaning → primer coating → top coat coating → inspection and acceptance
2.2 Base surface cleaning:
2.2.1 The paint coating of building steel structure engineering should be carried out after the steel structure installation is qualified. Before painting, clean up the rust, weld coating, welding spatter, oil stain, dust and other debris on the part to be painted.
2.2.2 The quality of base surface cleaning and rust removal is directly related to the quality of the coating.
2.2.3. Manual rust removal is to manually remove rust on steel components with scrapers, grinding wheels, emery cloth, and wire brush tools.
2.3 Primer coating:
2.3.1 Blending Hongdan anti-rust paint to control the viscosity, consistency and thinness of the paint. Stir fully when mixing to make the paint color and viscosity uniform.
2.3.2 When applying the first coat of primer, the brushing direction should be consistent and the connection should be neat.
2.3.3 The principle of frequent dips and short brushing should be adopted when painting to prevent the brush from dripping with too much paint.
2.3.4 After the first brushing is completed, a certain time interval should be maintained to prevent the second pass before the first pass is dry. This will cause the paint to flow and wrinkle and reduce the quality.
2.3.5 After the first pass is dry, apply the second pass. The direction of the second pass should be perpendicular to the direction of the first pass, so that the thickness of the paint film will be uniform.
2.3.6 After the primer is painted, it will take at least 4-8 hours to reach the surface dryness. The topcoat should not be painted before the surface dryness.
2.4 Top coat painting:
2.4.1 For the preparation of the top coat, a top coat with exactly the same color should be selected, the thinner mixed should be appropriate, and the top coat should be fully stirred before use to maintain a uniform color. Its working viscosity and consistency should ensure that it does not flow or show brushing during painting.
2.4.2 The topcoat should be continuously mixed during use, and the method and direction of painting are the same as the above process.
2.5 Coating inspection and acceptance:
2.5.1 During and after the surface coating construction, the painted workpieces should be protected to prevent flying dust and other debris.
2.5.2 The treatment inspection after painting should be that the color of the coating is consistent, the color is bright and bright, and there is no wrinkle or bumps.
2.5.3 For the measurement of coating film thickness, use a contact-type paint film thickness gauge to measure the thickness of the paint film. The paint film thickness gauge generally measures the thickness of 3 points and takes the average value.


Quality Standard 

3.1 The guarantee project shall meet the following requirements:
3.1.1 Varieties, models and quality of coatings, thinners and curing agents should meet the design requirements and the regulations of the current relevant national standards.
Inspection method: check the quality certificate or re-inspection report.
3.1.2 Derusting the steel surface before painting should meet the design requirements and the provisions of the current relevant national standards: the surface of the chemically derusted steel should show a metallic color. The surface of the processed steel should be free of welding slag, welding scar, dust, oil, water and burrs.
3.2 The basic items shall meet the following requirements:
3.2.1 Appearance quality of painting project:
Qualified: Brushing should be even, no obvious wrinkles, bubbles, and good adhesion.
Excellent: Brushing should be uniform, consistent color, no wrinkles, flow and bubbles, good adhesion, clear and neat color separation lines.


Finished product protection

4.1 After coating, steel components shall be temporarily fenced and isolated to prevent stepping on and damage the coating.
4.2 Do not touch acidic liquids to the painted steel components to prevent biting the coating.


Quality issues that should be paid attention to

5.1 The temperature of the coating operation should be between 5°C and 38°C. When the weather temperature is lower than 5°C, the corresponding low-temperature coating materials should be used for application.
5.2 When the temperature is higher than 40℃, the coating operation should be stopped. When the temperature of the component exceeds 40℃, the paint on the surface of the steel will produce bubbles, which will reduce the adhesion of the paint film.
5.3 When the air humidity is greater than 85%, or there is condensation on the surface of the component, coating operation is not suitable.
5.4 Before the production of steel components, the hidden parts of the components and the parts of the structure interlayer that are difficult to be derusted should be derusted and painted in advance.


Quality Records 

This process standard shall have the following quality records:
6.1 Qualification certificate of primer coating product for steel grid structure.
6.2 Certificate of conformity for top paint coating of steel grid structure.
6.3 The quality inspection record and report of the steel grid structure coating.