Has anyone in the industry introduced the technical principle and construction scheme of anticorrosive coatings for steel structures?

Technical principle of steel structure anticorrosive coating: water-resistant anticorrosive coating for steel structure based on high and medium temperature coal tar and its preparation method; Iron oxide pigment or the composition of mica iron oxide, zinc powder or zinc oxide, graphite or mica powder and aluminum silver powder is used as antirust pigment; The composition of calcium sulfate, talcum powder, magnetic clay or quartz powder is used as the main pigment. Weighing the components in proportion, heating and stirring evenly, cooling to normal temperature, adding solvent and stirring evenly. It has the characteristics of wear resistance, water resistance, alternating climate resistance, impact resistance, acid and alkali resistance and microbial corrosion resistance. It is especially suitable for anticorrosion of underwater steel gates and trash racks, and the anticorrosion period is 15 years.

1 preface

(1) According to the requirements of design institutes such as East China Institute, aiming at the corrosive environment of Iranian power plants and referring to the theoretical application effect of heavy-duty anticorrosive coatings in nuclear power plants, thermal power plants and bridges, high-performance heavy-duty anticorrosive coatings are recommended as a supporting scheme for corrosion protection of steel structure pipelines.

(2) In order to avoid corrosion of steel structure, prolong service life and ensure the quality of paint film, painting construction shall be carried out according to the requirements of bidding scheme.

(3) During paint coating construction, the products irrelevant to the benefit plan shall be surface treated and coated according to the provisions of the secret book to ensure the performance of the anti-corrosion coating.

2 Support recommendation scheme

(1) See table for anticorrosion matching scheme of buried pipelines (ordinary steel and cast iron).

1。 (2) See table for the anticorrosion supporting scheme of buried pipeline (galvanized steel).

2。 (3) See Table 3 for the anti-corrosion supporting scheme of empty pipes (general steel and cast iron) without insulation layer. (4) See table for anticorrosion supporting scheme of overhead pipeline (galvanized steel) without insulation layer.

4。 (5) See Table 5 for the anticorrosion supporting scheme of overhead pipeline with insulation layer (ordinary steel and cast iron).

(6) See table for anticorrosion supporting scheme of overhead pipeline (galvanized steel) with insulation layer.

6。 3 coating requirements

3. 1 Quality requirements for surface treatment (1) Ordinary steel shall be derusted by sandblasting to remove pure substances such as rust and scale. The quality control of surface treatment should reach Sa2 specified in GB8923 "Rust Grade and Derusting Grade of Steel Surface before Painting", the surface roughness is 35 ~ 75μ m, and the dust is removed after sandblasting. (2) The steel after sandblasting shall be painted for the first time within 4h. If ET-98 inorganic phosphate young effect zinc-rich coating is used, it is generally enough to remove oil and rust, and slight rust can also be brushed. (3) The welding parts cannot be painted within 72h after welding. The virtual consumption of paint is estimated by the construction site, such as lessons, construction degree and construction site combination, which is about 1.5 ~ 1.8 times of the actual consumption (Table 2- Table 6 * *). Within 3 months, zinc salt will appear on the surface of the paint film. When painting on the road during construction, the zinc salt on the surface of the paint film must be removed, and it can be polished with wet cloth or sandpaper for a while (Table 2- Table 6 and * * * at this stage). If the coating distance is too long, the coating of the paint film should be stopped after the surface of the paint film is sanded, so as to strengthen the interlayer adhesion of the paint film (Table 2- Table 5 shall prevail). (4) The galvanized layer must be lightly swept by sandblasting to remove impurities such as dust and oil stain, and then coated with 70h epoxy iron red antirust paint. 3.2 The coating environmental conditions have little effect on the quality of staggered paint film. In order to ensure the painting quality, the requirements for the painting environment are not high: (1) It is not allowed to expose to the sun in the dead of night and in rainy, foggy and snowy weather. Not suitable for construction, the basement temperature must be higher than 3℃ above the dew point before construction. ET-98 inorganic phosphate passivation zinc-rich coating might as well. ⑵ In winter, when the shading is bent and the basement temperature is lower than 60℃, construction cannot be carried out. When the temperature is below -5℃ in summer, 70h epoxy iron red antirust paint, H06-3 epoxy micaceous antirust paint and ZHL5 1-2 ultra-thick slurry epoxy asphalt antirust paint are not suitable for indoor construction in summer. (3) The painting process and paint film drying process cannot be constructed when there is dust flying. ET-98 3m inorganic phosphate long-acting zinc-rich coating is harmless, and the fruit dries thoroughly in 3 minutes. 4 Paint blending (1) First, check whether the variety and name of the paint meet the use requirements. ⑵ After the paint is opened, it should be fully stirred to mix the deposits evenly. (3) One-component coatings must be prepared in a hidden place according to the proportion, engineering dosage, allowable construction time and how long it takes. (4) Preparation method of coating ① The ratio of H06-1epoxy zinc-rich antirust primer is: component A: component B =4: 1 (weight ratio). Methods: The component B was reduced to the cylinder of component A, and it was placed for 20min minutes on average before use. ② The proportion of H06-3 epoxy micaceous iron antirust paint A and B is: component A: component B =4: 1 (component ratio). Methods: Add component B (curing agent) into the barrel of component A, stir it evenly and leave it for 20min minutes before use. ③ The proportion of ③70h epoxy iron red anticorrosive coating A and B is: component A: component B =4: 1 (weight ratio). Methods: Add the old barrel of component B (curing agent) into the barrel of component A, stir it evenly and let it stand for 20min minutes before use. ④ZHL5 1-2 ultra-thick epoxy asphalt antirust paint, the ratio of A to B is: component A: component B =4: 1 (component ratio). Methods: Add component B (curing agent) into the barrel of component A, stir it evenly, and let it stand for 20min minutes before use. ⑤ Chlorinated rubber topcoat method: Chlorinated rubber topcoat is canned paint, which can be used after being mixed evenly. 5 The construction method and parameters (1) can adopt airless low-pressure spraying, manual brushing or air spraying. ⑵ In order to ensure the thickness of paint film at the weld, corners and corners, a paint brush should be used for pre-coating before large-area painting. (3) When painting, the operator shall measure the wet film thickness with a wet film thickness gauge at any time to control the film thickness. (4) When painting, horizontal painting and vertical painting should be adopted to make the paint film smooth and even in thickness. 5] Before construction, please refer to the construction parameters in the manual and master the construction essentials. [6] In the case of high cost, ZH polyester modified topcoat or polyurethane paint can be used instead of chlorinated rubber topcoat, which has better anticorrosion effect. 6 Repair painting of paint film damage If the paint film is mechanically damaged outside the painting process, but the paint film of the topcoat is undamaged and partially rusted, pneumatic or electrostatic farm tools should be used to polish it to St2~St3 level specified in GB8923-88, and then H06 epoxy zinc-rich antirust topcoat and various supporting paints can be constructed. 7 Check (1) the surface treatment quality and compare it with the black-and-white photos outside the national standard of GB8923-88. ⑵ The internal inspection of paint film adopts naked eye to inspect the appearance of paint film, and the cooling tower is anticorrosive. The paint film should have defects such as pinholes, bubbles, cracks, dripping, dripping and missing coating. (3) Control of paint film thickness Measure the dry film thickness with a paint film thickness gauge, measure the paint film thickness after each painting, and measure the total paint film thickness after painting. Measure one point every 1 ~ 3m2 (or as otherwise specified). The film thickness of more than 90% measuring points reaches the specified value, and the film thickness that has reached the specified value is not less than 90% of the specified value. However, it should be painted or painted one by one. 8 Corrosion protection of temperature-resistant parts of steel structures and pipelines (1) For corrosion protection of temperature-resistant steel structures and pipelines, corresponding high-temperature anticorrosive primers, topcoats and silicone modified and inorganic modified high-temperature coatings shall be adopted. ⑵ Before coating the high temperature resistant coating, the first and second steel surfaces should be sandblasted, shot blasted, degreased and derusted, and then the primer and topcoat should be applied. In the case of unconditional sand blasting and shot blasting, it can be painted with 88- 1 degreasing, derusting and phosphating treatment agent, wiped with dry cloth after 24 hours, and then painted with WEH low temperature resistant topcoat. In the best scheme, the zinc-rich paint is passivated by ET-98 organic phosphate before the steel is treated like deformed paint nominally, and the temperature resistance is 200 ~ 600℃. At present, WEH 200 ~ 300℃, 400℃, 500℃ and 600℃ high-temperature resistant topcoats are applied twice. Generally, high-temperature resistant paints have one bottom and two sides, and the dry film thickness is about 30 ~ 90μ m. (3) The topcoats of low-temperature resistant paints above 400℃ can be in various colors, and it is best to choose silver ash, west ash and 600℃. (4) WEH silicone modified high-temperature resistant paint can be used for galvanized parts and metal parts, and the bottom surface may not be coated indirectly, but it can be coated three times alone. Take a brief look at the explanation book. 9 For the fire-proof parts of steel structure, the first coat is H06- 1 epoxy zinc-rich coating or 70h epoxy iron red primer, and ET-98 inorganic phosphate zinc-rich coating can also be applied. For the second time or more, apply thick steel structure fire retardant coating for several times, and the number of times depends on the fire prevention time. For general anticorrosion, provide 10 primer according to table 1 ~ table 6, and both ends of the paint remain unchanged. Two layers of chlorosulfonated polyethylene, two layers of alkyd paint, two layers of chlorinated polyphenylene ether paint and two layers of chlorinated polyethylene paint can also be used, or a matching scheme can be designed according to the requirements of construction for the paint. 1 1 Other matters (1) Paint should be stored in a ventilated, breathable and fireproof place, away from kindling. ⑵ Compared with other primer coatings, ET-98 inorganic phosphate long-lasting zinc-rich coating has the characteristics of 1-4 times higher anticorrosion effect, dry and dull, short construction period and long indoor anticorrosion effect. When preparing and using, component A is 1 (liquid) and component B is 2 (powder). Pour the component A into the powder end of the component B, and add about 15% of ET thick material in time after stirring. Curing for 20 minutes, brushing, wetting for 3 minutes and drying for 3 hours. Volts conduct electricity, and a thin phosphating film is formed on the steel surface, which is isolated from the air. (3) When using various coatings, we should pay attention to the warranty period of the products, and recheck the warranty period before painting. (4) When the coating construction stops, the paint bucket shall be covered in time. And use the corresponding thick materials to wash hands and washing tools. The number of anticorrosive coatings for steel structure pipelines depends on the surface treatment of steel structure, the selection of anticorrosive coatings and reasonable construction. According to the requirements of East China Electric Power Design Institute and other design institutes, Toyo Bianxiao also introduced the selection and matching of anti-corrosion coatings, the quality requirements of surface treatment before painting, the environmental conditions of painting, the preparation of coatings, the construction and inspection of coatings, etc. In view of the corrosion situation of Iranian power plants, it can be used for readers' reference. 1 Foreword (1) According to the requirements of East China Electric Power Design Institute and other design institutes, in view of the corrosive environment of Iranian power plants, and referring to the theoretical application results of anti-corrosion coatings in nuclear power plants, hydropower stations, thermal power plants and bridges, it is recommended to apply high-performance heavy-duty anti-corrosion coatings as a supporting case for anti-corrosion of steel structure pipelines. (2) In order to avoid the corrosion of steel structure, prolong the service life and ensure the quality of paint film, the paint coating construction should be carried out according to the requirements of the benefit plan. (3) In the process of paint coating construction, it is necessary to apply paint coating according to the product specifications irrelevant to the bidding scheme to ensure the performance of the anticorrosive coating. 2 Recommended supporting scheme (1) See table 1 for the supporting anti-corrosion scheme for buried pipelines (ordinary steel and cast iron). (2) See Table 2 for the anticorrosion supporting scheme of buried pipeline (galvanized steel). (3) See Table 3 for the anticorrosion matching scheme of hollow pipes (general steel and cast iron) with insulation layer. (4) See Table 4 for the anticorrosion supporting scheme of overhead pipeline (galvanized steel) without insulation layer. (5) For overhead pipelines with insulation layer, see Table 5 (common steel and cast iron) for the anticorrosion supporting scheme. (6) See Table 6 for the anticorrosion supporting scheme of overhead pipeline (galvanized steel) with insulation layer. 3. Painting requirements 3. 1 Nominal processing quality requirements (1). Ordinary steel should be derusted by sandblasting to remove pure substances such as rust and scale. The quality control of surface treatment should reach Sa2 specified in GB8923 "Rust grade and derusting grade of steel surface before painting", the surface roughness should be 35 ~ 75μ m, and the dust should be removed by sandblasting first. (2) After sandblasting, the first paint coating shall be completed within 4h. If ET-98 organic phosphate low-efficiency zinc-rich coating is used, it is not necessary to remove oil and rust separately, and it can be coated with slight corrosion. (3) Within 72 hours before welding, the welding parts cannot be painted. The class hours, construction degree, construction site and other conditions of international application of coatings are estimated by construction replacement, which is about 1.5 ~ 1.8 times of the actual consumption (the same as in Table 2- Table 6). Within 3 months, zinc salt will appear on the surface of the paint film. In the next painting, the zinc salt on the surface of the paint film must be removed and polished with dry cloth or sandpaper (Table 2- Table 6 are the same). If the coating distance is too long, before the paint film becomes rough, a layer should be coated in the name of sandpaper to strengthen the interlayer adhesion of the paint film (Table 2- Table 5 and this stage * * *). (4) The galvanized layer must be lightly swept by sandblasting to remove pure substances such as dust and oil stain, and then coated with 70h epoxy iron red antirust paint. 3.2 coating environment conditions the coating environment has a great influence on the quality of the paint film. In order to ensure the painting quality, there are no following requirements for the painting environment: (1) Do not expose yourself to the sun at night or paint with the ground in rainy, foggy and snowy weather. When the absolute humidity is more than 85% and the basement temperature must be higher than 3℃, it is not suitable for construction. ET-98 inorganic phosphate young effect zinc-rich coating might as well. ⑵ In winter, when the shading is bent and the base material is warmer than 60℃, construction cannot be carried out. When the temperature is below -5℃ in summer, 70h epoxy iron red antirust paint, H06-3 epoxy micaceous antirust paint and ZHL5 1-2 ultra-thick slurry epoxy asphalt antirust paint are not suitable for indoor construction in summer. (3) When there is dust flying in the process of painting and film drying, construction cannot be carried out. ET-98 3m inorganic phosphate coating with young effect and rich zinc is harmless, and the fruit dries thoroughly in 3 minutes. 4 Paint blending (1) First check the variety and name of the paint to see if it meets the use requirements. (2) After the coating is closed, it should be fully stirred to make the deposit mix evenly. (3) One-component coating must be prepared in a hidden place according to the proportion specified in the clarification, the engineering quality, the allowed farming time and the use time. (4) Preparation method of coating ① The preparation ratio of epoxy zinc-rich antirust primer H06- 1 is: component A: component B =4: 1 (weight ratio) Method: Add component B into the vat of component A, stir it evenly, and let it stand for 20 minutes before use. ② The proportion of H06-3 epoxy micaceous iron antirust paint A and B is: component A: component B =4: 1 (sedimentation ratio). Methods: Pour the component B (curing agent) in the vat into the component A, stir it evenly, and let it stand for 20 minutes before use. ③ The proportion of ③70h epoxy iron red anticorrosive coating A and B is: component A: component B =4: 1 (sedimentation ratio). Methods: Add component B (curing agent) into the barrel of component A, stir it evenly, and let it stand for 20 minutes before use. ④ZHL5 1-2 ultra-thick epoxy asphalt antirust paint A and B mixing ratio: component A: component B =4: 1 (weight ratio) Method: Add component B (curing agent) into the barrel of component A, stir it evenly, and let it stand for 20min before use. ⑤ Chlorinated rubber topcoat method: Chlorinated rubber topcoat is canned paint, which can be used after being mixed evenly. 5. The construction method and parameters (1) can be low-pressure airless spraying, manual brushing or air spraying. ⑵ In order to ensure the thickness of paint film at welds, corners and edges, a paint brush should be used for pre-coating before large-area painting. (3) When painting backwards, the operator shall measure the wet film thickness with a wet film thickness gauge at any time to control the film thickness. (4) When painting, horizontal painting and vertical painting should be adopted to make the paint film smooth and even in thickness. 5] Before construction, please refer to the construction parameters in the dark book and master the construction essentials. [6] In the case of high cost, ZH polyester modified topcoat or polyurethane topcoat can be used instead of chlorinated rubber topcoat, and the anticorrosion effect is better. 6 Repair and painting of paint film damage If the paint film is mechanically damaged during painting, but the underlying paint film is not damaged and partially rusted, it should be polished to St2~St3 level specified in GB8923-88 standard by static wind or electrostatic tools, and H06 epoxy zinc-rich antirust primer and various supporting paints can be constructed. 7 Inspection (1) The surface treatment quality should be compared with the black and white photos in the national standard GB8923-88. ⑵ Paint film inspection: Check the surface state of the paint film with naked eyes, and the paint film shall be free of defects such as pinholes, bubbles, cracks, dripping, dripping and missing coating. (3) Control of paint film thickness Measure the dry film thickness with a paint film thickness gauge, measure the paint film thickness after each painting, and measure the total paint film thickness after painting. Measure one point every 1 ~ 3m2 (or as otherwise specified). The film thickness of measuring points below 90% reaches the specified value, and the film thickness that has reached the specified value is not less than 90% of the specified value. However, one layer should be shaved or reduced. 8 Corrosion protection of temperature-resistant parts of steel structures and pipelines (1) For corrosion protection of heat-resistant steel structures and pipeline temperature-resistant parts, corresponding low-temperature anti-corrosion primers, spot paints and inorganic modified high-temperature coatings should be adopted. ⑵ Before coating the high-temperature resistant coating, the steel surface should be sandblasted, shot blasted, degreased and derusted, and then the primer and topcoat should be applied. Under the condition of unconditional sand blasting and shot blasting, 88- 1 degreasing, derusting and phosphating treatment agent can be used before painting, and WEH high-temperature resistant primer can be painted after being wiped with wet cloth for 24 hours. In the best scheme, after the corrosion protection of steel structure, the steel surface is treated with deformation paint, and then it is painted with ET-98 organic phosphate inefficient zinc-rich paint, which can withstand the temperature of 200 ~ 600℃. At present, the high-temperature topcoat of WEH at 200 ~ 300℃, 400℃, 500℃ and 600℃ is twice, and the high-temperature paint can be one bottom and two sides, and the dry film thickness is 30 ~ 900. (3) The topcoat color of high temperature resistant coatings can be in various colors above 400℃, and silver gray, medium gray, thick gray, dark black, medium yellow and medium green should be selected at 400 ~ 600℃. (4) WEH silicone modified high-temperature resistant paint can be used for galvanized parts and metal parts, and the bottom surface is not necessarily indirectly painted, so ordinary three coats can be used. See explanation. 9 Waterproof parts of steel structure should be coated with H06- 1 epoxy zinc-rich coating or 70h epoxy iron red primer, or ET-98 inorganic phosphate zinc-rich coating. After the second time, the thick steel structure waterproof coating shall be applied for several times, and the number of times shall depend on the fire prevention time. 10 single anticorrosion requirements Primer shall meet the construction requirements in Table 1 ~ Table 6, or two layers of chlorosulfonated polyethylene topcoat, alkyd topcoat, highly chlorinated polyphenylene ether topcoat and highly chlorinated polyethylene topcoat may be used, or a matching scheme may be designed according to the painting requirements of construction. 1 1 Other matters (1) Paint should be stored in a ventilated, breathable and fireproof place, away from kindling. ⑵ Compared with other primer coatings, ET-98 organic phosphorus low-efficiency zinc-rich coating improves the anticorrosion effect by 1-4 times, and has the characteristics of dry and dull, short construction period and poor indoor anticorrosion effect. When preparing and using, the component A is 1 (liquid) and the component B is 2 (powder). Pour the component A into the powder of the component B, and add the ET material 15% in time after stirring. It can be applied after curing for 20min minutes, and the surface is dried for 3 minutes and the name is dried for 3 hours. Volts conduct electricity, and a thin phosphating film naturally forms on the steel surface, which is isolated from the air. (3) Pay attention to the shelf life of products when using various coatings. After the expiration of the warranty period, it should be inspected again before painting.