1. Determine the five characteristics of non-metallic inclusions in square and rectangular tubes

Precision steel pipes and seamless steel pipes are two common steel pipe products on the market. They have some similarities, but there are also differences.

The reason why straight seam steel pipes are widely used in the market is due to their unique characteristics. In the welding process, the cost of the process used is relatively low, and straight seam steel pipes can be manufactured using the manufacturing processes of forged steel, extrusion, rolling and drawing steel, and their specifications are relatively certain, which provides the possibility for wide application sex.

At present, prefabricated polyurethane directly buried thermal insulation pipes are used in many industrial applications. In order to avoid the development of this situation, it is also important to do corresponding rust prevention work.

Spiral steel pipe is a spiral seam steel pipe made of strip steel coil as raw material, extruded at constant temperature, and welded by automatic double-wire double-sided submerged arc welding process.

The diameter expansion of straight seam welded pipe is a pressure processing technology that uses hydraulic or mechanical means to apply force from the inner wall of the steel pipe to expand the steel pipe outward in the radial direction.

The insulation material used in general insulation steel pipes is mostly rigid polyurethane foam, which can adapt to temperatures of -185 to 95°C. This kind of insulation material has a soft texture. In order to improve its strength, we need to apply an anti-corrosion coating on the outside of the insulation layer, so we also call this steel pipe an anti-corrosion insulation pipe.

The spiral steel pipe feeds the strip into the welded pipe unit. After being rolled by multiple rollers, the strip is gradually rolled up to form a circular tube blank with open gaps. Adjust the reduction amount of the kneading roller to control the weld gap between 1~ 3mm, and make both ends of the welding joint flush. If the gap is too large, the nearby effect will be reduced, the eddy current heat will be insufficient, and the inter-crystal bonding of the weld will be poor, resulting in non-fusion or cracking.

Epoxy resin anti-corrosion steel pipe is a kind of steel pipe, and its surface coating is a two-component, high-solid coating with epoxy resin as the main agent. Widely used in drinking water tanks, water pipes, water tanks, etc.

In recent years, many cities in my country have built sewage treatment plants. Most of the water pipelines in urban sewage treatment projects are steel pipes laid underground. Corrosion problems are a major problem in sewage treatment projects. The quality and lifespan of buried water pipelines directly affect the entire project. Therefore, it is very important to prevent corrosion of buried pipelines in urban sewage treatment projects.