The development of fused epoxy coatings in China began in the late 1970s and developed in the 1980s.In the 1990s, while expanding the application of engineering, the development of coating performance took the American 3M company 206N as the target to catch up, and made gratifying progress.Especially in curing time has dropped below 230-240 ℃ / 3 min, not only makes the process simplified, large diameter stainless steel pipe coating at the same time embodies the hard, thin layer, high performance three advantages, cause the attention of the stainless steel pipeline engineering.

(1) process flow of large-caliber stainless steel pipe coating: dry surface, sand blasting (shot), medium frequency induction heating, electrostatic powder spraying, constant temperature (solidification), cooling test.

(2) surface treatment of large-caliber stainless steel pipe: it must be treated with sand-blasting c pellet to the SIS sa2% level, and the roughness shall not be less than 50t/m.Due to the impact resistance of coating materials, adhesion, and bending rigidity are relation with surface treatment, in order to improve the performance of the internal coating, usually by heat treatment before sandblasting, remove the crystal water and oil content in the rust layer.To ensure the roughness, two sandblasting (shot) processes are adopted.Even after sand blasting (shot) treatment, chemical treatment should be carried out, the purpose of which is to improve the adhesion of the coating.

(3) stainless steel spraying process: using friction electrostatic spraying technology, electrostatic voltage 20,000 ~ 30,000 V.In order to improve the adhesion of coating, foreign countries also pay attention to the development of composite powder coating technology on the bottom surface.
Curing process: as the curing time of powder coating is shortened, curing process is simplified.206 n series, such as the United States 3 m 200 ℃ when the gel time of 22 ~ 27 s, curing time is 1 ~ 5 min, can be divided into fast and slow, standards, three kinds of models.The heating equipment adopts medium frequency induction heating, which not only shortens the length of the process line, but also improves the thermal efficiency and prevents oxidation of the interface.Thick wall stainless steel pipe, stainless steel thick wall pipe, large diameter thick wall pipe, large diameter thick wall pipe.