Common Anti-corrosion Treatment Techniques
Coating Anti-corrosion
This is a relatively common method. Common coating materials include epoxy resin and polyethylene. Taking epoxy resin coating as an example, it can form a dense protective film on the surface of steel bellows, effectively isolating water, oxygen and corrosive media from contact with steel. Moreover, the epoxy resin coating has strong adhesion, can remain stable for a long time, and is not easy to fall off, providing reliable protection for the steel corrugated pipe.

Galvanizing Anti-corrosion: A layer of zinc is applied to the surface of the steel corrugated pipe by hot-dip galvanizing or electro-galvanizing. Zinc is more chemically active than iron. In a corrosive environment, zinc will corrode first, thus protecting the steel. The hot-dip galvanized zinc layer is thicker and has a better anti-corrosion effect. It is suitable for some occasions with high anti-corrosion requirements, such as underground drainage pipes.

Cathodic protection is an electrochemical protection method that applies an electric current to the steel bellows, making it the cathode and thus inhibiting the corrosion of the steel. The sacrificial anode method is usually used to connect metals that are more active than steel (such as magnesium, zinc, etc.) to the steel bellows. The active metal acts as the anode and continuously dissolves, protecting the steel bellows as the cathode.

The precision rolled seamless steel pipe is made by hot rolling or cold rolling and other precision processing technologies. After the solid steel billet is pierced, it goes through multiple rolling and finishing processes to make the pipe wall uniform, with high dimensional accuracy and good surface finish.
Ordinary steel pipes are usually produced by welding or simple extrusion molding. The production process is relatively simple, and the precision and surface quality are not as good as those of precision-rolled seamless steel pipes.

The precision rolled seamless steel pipe has excellent mechanical properties, such as high strength, high toughness, good fatigue resistance and high pressure resistance. This is because its internal structure is uniform, without defects such as welds, and it can better withstand various stresses and working conditions. The production process of the finished rolled tube can produce dimensional equipment and high-precision dimensions below 0.1 mm. The finished rolled tube has a smooth surface and high dimensional accuracy.
Due to the presence of welds, the mechanical properties of ordinary steel pipes are relatively poor, especially when subjected to high pressure, high temperature, or alternating loads; they are prone to problems such as cracks and leakage. Ordinary rolled tube products may have large dimensional errors.

Stainless steel medium and thick plates refer to steel plates with a thickness ranging from 4 to 25.0 mm. Depending on the thickness, it can be further subdivided into:
Thicknesses between 25.0 and 100.0 mm are called thick plates.
Plates with a thickness exceeding 100.0 mm are called extra thick plates.

Physical properties: Its boiling point is 872°C (some say it is 2730°C), melting point is 1398°C, density is 7.93g/cm³, thermal conductivity is 20W/m·K, and elastic modulus is 190MPa (or 190GPa, 1GPa=1000MPa). Mechanical properties: High plasticity, toughness and mechanical strength. The tensile strength specimen can continue to elongate without increasing the force during the tensile test, and the elongation is not less than 5% during the tensile test.

Corrosion resistance: atmospheric corrosion resistance, acid resistance, pitting and crevice corrosion resistance, and stress corrosion cracking resistance are all good, but the specific performance is related to alloy factors.

Heat resistance: Good high temperature strength, but slightly inferior to some high temperature alloys; high temperature brittleness, high temperature oxidation and sulfidation performance are also good.