SSAW steel pipe production process is simple, production efficiency is high, cost is low, and development is rapid. The strength of SSAW steel pipes is generally higher than that of LSAW steel pipes. Welded pipes with larger diameters can be produced from narrower billets, and welded pipes with different diameters can also be produced from scrap materials of the same width. However, compared with LSAW steel pipes of the same length, the weld length is increased by 30~100%, and the monthly production speed is lower. In order to extend the service life of most SSAW steel pipes, anti-corrosion treatment is necessary. In daily care work, it is not only necessary to perform surface anti-corrosion treatment on SSAW steel pipes, but it is also very important to learn how to avoid wear and tear during daily installation and use of SSAW steel pipes. This is related to some safety issues in the entire pipeline line, and also avoids the trouble of frequent maintenance in daily work.
We can first understand how to remove the rust of the SSAW steel pipe, which is divided into two types: sandblasting and shot blasting: shot blasting is the high-speed impact of the high-speed rotating small steel ball or iron ball on the surface of the part, so the oxidation layer on the surface of the part can be far away. Sand blasting is a method of using compressed air to quickly sweep the surface of quartz sand. Not only rust, but also remove oil, which is very effective for painting. It is often used to remove rust from the surface of parts. In this way, after rust removal, the surface of the SSAW steel pipe is rough, and the surface oil dirt is removed. It has certain adhesion to anti-corrosion winding and paint. SSAW steel pipe after anti-corrosion treatment, it is difficult to effectively protect the internal rust.
Steel pipes have large specifications and high transportation efficiency, which can save pipeline laying. They are mainly used for the transportation and paving of oil and natural gas tubing and casing. They must be anti-corrosion steel pipes. Anti-corrosion steel pipes are a kind of composite pipes. The base pipes are SSAW steel pipes. SSAW steel pipe production Welded steel pipes generally use single-wire or double-wire submerged arc welding, and then use automatic submerged arc welding for repair welding after being rolled into steel pipes.
Surface pretreatment for anti-corrosion of SSAW steel pipes
1. The level of surface degreasing purification and spray cleaning should comply with the relevant provisions. The working environment must meet the working conditions of relative air humidity .
2. lower than 85% and steel structure surface temperature not lower than 3°C above the dew point.
3. The compressed air used for spray cleaning must be processed by the cooling device and the oil-water separator. The oil-water separator must be cleaned regularly to ensure that the compressed air is dry and oil-free.
4. The working pressure of the jet sandblasting machine is generally 0.5-0.71Pa; the pressure at the nozzle of the sandblasting machine is generally 0.35-0.51Pa, but for wall components with a wall thickness less than 4mm, the pressure can be slightly lower than the lower limit.
5. The distance between the nozzle and the surface of the steel structure to be sprayed is generally 100-300m; the angle between the spray direction and the normal line of the surface of the steel structure to be sprayed is preferably 15°~30°.
6. When the nozzle orifice is worn to the point where the diameter increases by 25%, the nozzle should be replaced.
7. The abrasive used for spray cleaning must be clean and dry. The type and particle size of the abrasive should be selected based on the original degree of rust on the surface of the steel structure, the spraying process, cleanliness and surface roughness required by the design or coating specifications. Generally, for steel components with a wall thickness greater than or equal to 4m, the particle size range of the abrasive selected is 0.5-1.5m. For steel components with a wall thickness less than 4m, abrasives with a smaller density should be selected.
8. The abrasives used in pressure blasting (sandblasting) are generally only used once. If they need to be recycled, they should be screened and dried.
9. Manual and power tool rust removal is only suitable for local repair of coating defects and situations where spray cleaning is not possible.
10. After surface cleaning, use a vacuum cleaner or dry, clean compressed air to remove floating dust and debris. Do not touch the cleaned surface with your hands.
11. The cleaned steel structure surface should be painted with primer in time. If the surface is found to be contaminated or rusty before painting, it should be cleaned again to the original required surface cleanliness level.
12. The manufacturers of pressure vessels such as air compressors and sandblasting tanks used in pressure sandblasting must hold a pressure vessel production license issued by the relevant national departments.
13. Sandblasting workers should wear protective gear when performing sandblasting operations to protect their bodies from splashing abrasives; when working in the workplace, the breathing air should be purified.
14. Pay attention to dust prevention and environmental protection when working in the open air, and comply with relevant national laws and regulations.
15. Carry out coating protection.
The above are some precautions and processes for the anti-corrosion of SSAW steel pipes. It is crucial to do a good job in the anti-corrosion of SSAW steel pipes and must be improved according to the relevant processes.