What process is used for plastic coated steel pipes

The main method of the composite process of Shajiabang brand "plastic-coated composite steel pipe, base pipe and coating" is to preheat the base pipe first, so that the surface temperature meets the temperature range required by the plastic powder, and then coat the plastic powder with the highest temperature control, and the powder is also known as the dispersion method, which can be distinguished as:

spraying (spraying plastic powder with compressed air through a spray gun);

Suction coating (vacuum pump is used to form a negative pressure in the tube to suck the plastic powder in);

drenching (storing plastic powder in a container and then drizzling it over the tube);

impregnation (storage of plastic powder in a container, immersion of the preheated base tube in the powder);

Rotational molding (plastic powder is stored on the wall of the base tube, and the base tube is rotated to distribute the powder evenly).

Because the surface of the base tube reaches a certain temperature, the plastic powder is melted and coated on the pipe wall after it is on the pipe wall to form a coating and form an anti-corrosion layer.

The tightness of the inner coating and the base tube is related to a variety of factors, such as the type of heating equipment, heating method, fuel type, heating temperature, fineness of plastic powder, additive composition, etc., but the most critical is surface pretreatment. Under the premise of surface pretreatment standards, the comprehensive index is assessed by adhesion, and the original standard for adhesion index in China's standard is low, which has been improved (polyethylene coating 30N 10mm, epoxy resin coating is 1 3 grades), this standard is close to developed countries. But taking these measures can not completely eliminate the problem of coating peeling, one of the reasons, galvanized steel pipe and welded steel pipe are heated in the heating furnace, because the galvanized steel pipe surface has an extra layer of galvanized layer, and the galvanized layer has a reflective effect on heat at the same time, plus the galvanized layer improves the surface finish of the steel pipe and reduces the absorption of heat, so the coating effect of the plastic-coated steel pipe with the galvanized steel pipe as the base pipe is not as good as the plastic-coated steel pipe with the welded steel pipe as the base pipe.

According to industry experts, the plastic powder is mixed with a certain adhesive, and the coating can be firmly bonded to the steel pipe wall after the composite process, and the adhesion index can be fully qualified when testing, but the adhesive has an expiration date, and the validity period is over (generally three months), the coating will fall off, which will block the water flow channel and cause accidents, with serious consequences. Therefore, in order to truly solve the quality problem of plastic-coated steel pipes, we must rely on the brand and put an end to fake and shoddy products, so that users can rest assured, make plastic-coated steel pipes invincible, and eventually replace the position of galvanized steel pipes.

1. A layer of polyethylene plastic is evenly coated on the inner wall of the hot-dip galvanized steel pipe. This kind of pipe is mainly used for plastic-coated composite steel pipe, which is based on steel pipe, and melt spraying or adsorption food-grade epoxy powder on the inner wall through a special process.