1. Spraying methods:Mainly in static spraying and hot spraying.
2. Oil removing, desiccation: It always fires the surface of pipelines to remove oil stain and moisture.
3. Ball blast or spray sand: The surface process quality should reach Sa2 1/2 grade, anchor wrinkle should be in the scope of 40~ 100 um. After processing, it should be cleared right away, and spray in 8 hours.
4. Warm-up: Medium frequency induction heating methods. When used in single FBE, the temperature should be controlled in the scope of 210~ 250℃; when used in 3PE, the temperature should be controlled in the scope of 180-200℃. (Notice: the heating temperature of steel tube should not be higher than 260℃)
5. Leak hunting: For single FBE, when the film temperature is lower than 100℃, we always use electric sparkle leak hunting equipments to inspect all the coating of each tube with the voltage of 5V/um; and the voltage of 25 KV during the leak hunting of 3PE. |