Stainless steel square tube:
hollow strip of steel called a square tube because its cross-section is square.
A large number of pipes are used to transport fluid, such as oil, natural gas, water, gas, steam, etc. In addition, when bending and torsional strength are the same, the weight is light, so they are also widely used to manufacture Machine element and engineering structures.
Metals can react with oxygen in the atmosphere to form an oxide film on the surface.
The iron oxide formed on ordinary carbon steel will continue to oxidize, causing corrosion to expand and ultimately forming pores. This can be achieved by electroplating with paint or oxidation resistant metal to protect the surface of carbon steel, but this protective layer is only a thin film. If the protective layer is damaged, the steel below will begin to rust again. Whether stainless steel pipes are corroded is related to the chromium content in the steel. When the chromium content in the steel reaches 12%, a layer of passive and dense chromium rich oxide is formed on the surface of stainless steel pipes in the atmosphere to protect the surface and prevent further oxidation. This type of oxide layer is extremely thin, through which the natural luster of the steel surface can be seen, giving stainless steel a unique surface. If the chromium film is damaged, the chromium in the steel and the oxygen in the atmosphere will regenerate a passivation film, continuing to play a protective role. In some special environments, stainless steel may also experience localized corrosion and failure, but unlike carbon steel, stainless steel does not undergo uniform corrosion and failure, so the corrosion allowance is meaningless for stainless steel pipes
