Stainless steel square tube is a long hollow steel, which is called square tube because of its square cross section. A large number of pipes are used for conveying fluids, such as oil, natural gas, water, gas, steam, etc. in addition, when the bending and torsional strength are the same, they are light in weight, so they are also widely used for manufacturing mechanical parts and engineering structures.

Stainless steel square tube is a long hollow steel, which is called square tube because of its square cross section. A large number of pipes are used for conveying fluids, such as oil, natural gas, water, gas, steam, etc. in addition, when bending and torsional strength are the same, they are light in weight, so they are also widely used for manufacturing mechanical parts and engineering structures.

Classification of stainless steel square pipes: square pipes are divided into seamless steel pipes and welded steel pipes (seamless pipes). According to the cross-sectional shape, it can be divided into square and rectangular pipes. Circular steel pipes are widely used, but there are also some semi-circular, hexagonal, equilateral triangle, octagonal and other special-shaped steel pipes.

For stainless steel square pipes that bear fluid pressure, hydraulic test shall be carried out to check their pressure resistance and quality. It is qualified if there is no leakage, wetting or expansion under the specified pressure. Some steel pipes shall be subject to crimping test, flaring test, flattening test, etc. according to the standards or the requirements of the demander.

Square pipe specification: 5 * 5 ~ 150 * 150 mm thickness: 0.4 ~ 6.0 mm

Square pipe material: 304, 304L, TP304, TP316L, 316, 316L, 316Ti, 321, 347h, 310S.

Round steel preparation → heating → hot rolling piercing → head cutting → pickling → grinding → lubrication → cold rolling → degreasing → solution heat treatment → straightening → pipe cutting → pickling → finished product inspection.

The metal can react with oxygen in the atmosphere to form an oxide film on the surface. The iron oxide formed on the ordinary carbon steel will continue to oxidize, expanding the corrosion and eventually forming holes. This can use paint or oxidation-resistant metal for electroplating 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 start to rust again. Whether the stainless steel pipe is rusted is related to the chromium content in the steel. When the chromium content in the steel reaches 12%, a passivated and dense chromium rich oxide is formed on the surface of the stainless steel pipe in the atmosphere to protect the surface and prevent further reoxidation. This kind of oxide layer is extremely thin, through which you can see the natural luster of the steel surface, making stainless steel have a unique surface. If the chromium film is damaged, the chromium in the steel and oxygen in the atmosphere will regenerate a passivation film to continue to play a protective role. In some special environments, stainless steel will also fail due to some local corrosion, but unlike carbon steel, stainless steel will not fail due to uniform corrosion, so the corrosion allowance is meaningless for stainless steel pipes