polyurea is a unique chemical product. Because polyurea, a chemical product, has certain elasticity, we will use polyurea as a material in many chemical processing aspects. Although polyurea is a very common material, not many people know the construction scheme of polyurea. How to use polyurea is also a big problem for many people. Then, Xiaobian will introduce the polyurea construction plan to everyone, so that everyone can use polyurea well.
Preparation of construction materials:
The materials shall be ordered within 7 days before the commencement of construction. Before ordering, we will ask the owner's representative to inspect the production process, testing means and testing methods of the materials, and sign an order contract when the performance of the materials meets the design requirements.
main construction methods:
(1) sandblasting for rust removal:
1. surface treatment methods:? Dry sand blasting is used to remove rust. In order to reduce environmental pollution and create a relatively less dust environment for operators, quartz sand is used as abrasive. ? Pretreatment: The weld burrs, welding slag and spatter on the surface weld that need anti-corrosion treatment should be polished off. Structural corner, uneven surface and weld surface should be polished flat or smooth transition. Grease and oil stains should be thoroughly removed with alcohol (industrial pure) or acetone (industrial pure).
2. Key points of sand blasting derusting operation:
① For large equipment, the method of sand blasting in sections can be adopted. That is to say, a certain area should be sandblasted for rust removal, and the first primer should be painted after passing the inspection. After the primer is solidified, the remaining part should be sandblasted for rust removal. At this time, the coated primer should be protected, and a distance of at least 5mm should be reserved at the end where it continues to be sandblasted. Enable cross sandblasting, thus ensuring the quality of sandblasting. The surface qualified by sandblasting inspection shall be painted again, and the first primer shall be cleaned with alcohol or acetone. ? (2) The quality level achieved by sandblasting shall be above GB8923-88Sa2.5, and all impurities such as grease, scale and rust products on the metal surface shall be completely removed, and the dust shall be removed with a vacuum cleaner, dry and clean compressed air or a brush. The area slightly discolored by residual rust spots and scale shall not exceed 5% in any area of 1×1mm2, and the roughness shall be RZ≥7μm m..
③ The compressed air used for sandblasting should be dry and clean, and it should not contain oil, sundries and moisture, and the pressure should be .5-.6Mpa. Before use, compressed air should be sprayed on clean white cloth. After staying for 1min, check the white cloth with naked eyes. If no oil stain, black spots and moisture are found, it can be used.
(4) the sand particles for sand blasting are quartz sand, which should be dry and clean, free of oil stains and sundries; The water content should be less than 1%. If necessary, it should be baked and dried, and it can only be used after it is cooled.
⑤ The technological indexes of sandblasting construction are as follows: nozzle diameter is 6 ~ 8 mm, spraying angle is 3 ~ 75, and spraying distance is 8 ~ 2 mm
(2) Polyurea elastomer spraying construction method:
Metal substrate treatment? Firstly, the substrate is sandblasted to Sa2.5 level, and the defective parts such as welds are leveled with caulking material, so that the whole substrate can be smooth and excessive. After the caulking material is solidified, it is smoothed with a grinding wheel. Then clean the substrate and roll or brush two matching primers. The longest interval for repainting primer is 24 hours and the shortest interval is 3 hours.
summary: xiaobian introduced the construction scheme of spraying polyurea in the above. Generally speaking, for polyurea spraying, different materials and materials with different areas have different construction methods. However, no matter which construction scheme is good, we must ensure that polyurea can be fully covered without gaps. Therefore, when spraying polyurea, we must use different methods because of different materials, and at the same time, different materials have different drying methods and operation methods, which need more attention.
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