Galvanized steel is generally covered with a zinc layer on the surface of the steel plate to prevent corrosion. However, in some places with high humidity and humid climates, the protective ability of the zinc layer may be damaged, resulting in the formation of white zinc oxide on the surface, which is the cause of white rust.
1. High air humidity
2. Low oxygen content in the air, such as a high proportion of acidic gases in the environment
3. Direct contact with other metals
4. Packaging when drying is not thorough
5. Mechanical damage caused by storage extrusion.

The roughness of seamless steel pipe refers to the unevenness of the surface of the pipe wall. This indicator is crucial to the performance and appearance of the steel pipe. Generally speaking, the inner and outer surface roughness of seamless steel pipes is controlled below Ra 0.8μm. It ensures that the steel pipe has good wear resistance, corrosion resistance, and sealing during use, and it is easier to achieve better sealing performance and thermal conductivity.

Spiral steel pipes are completely called spiral welded steel pipes. It is a spiral steel pipe that uses automatic double-wire submerged arc welding technology, with strip steel coils as raw materials, often using warm extrusion molding and double-wire double-sided automatic submerged arc welding technology, with spiral welds on the surface, called spiral welded pipes.
Threaded steel pipe refers to the outer surface of the steel pipe pressed by embossing equipment. Threaded pipes, also known as low-rib pipes, mainly rely on external rib pipes (rib coefficient is 2-3) to expand the heat exchange area and are usually used when the heat transfer coefficient inside the pipe is more than 1 times higher than that outside the pipe.

Threaded steel pipes have good connectivity and sealing properties, so they are widely used in pipeline systems in industries such as petroleum, chemical industry, and natural gas, as well as in connection and fixing parts in fields such as construction and machinery.
The spiral pipe, due to its unique spiral structure, plays an important role in drainage, sewage, ventilation, and other occasions that require flexible connection and bending performance.