Stainless steel square tube：

Introduction：

The stainless steel square tube is a hollow long steel bar. Because the cross section is square, it is called a square tube. A large number of pipelines used to transport fluids, such as petroleum, natural gas, water, gas, steam, etc. In addition, when the bending and torsional strength are the same, the weight is light, so it is also widely used in the manufacture of mechanical parts and engineering structures.

Classification：

Stainless steel square tube classification: square tube is divided into seamless steel pipe and welded steel pipe (seam pipe). According to the shape of the section, it can be divided into square and rectangular tubes. Round steel tubes are widely used, but there are also some semi-circular, hexagonal, equilateral triangle, octagonal and other special-shaped steel tubes.

For stainless steel square pipes that are subjected to fluid pressure, hydraulic tests are required to check their pressure resistance and quality. No leakage, wetting or expansion under the specified pressure is qualified. Some steel pipes are also rolled according to standards or demander requirements Side test, flaring test, flattening test, etc.

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

Material of square tube: 304, 304L, TP304, TP316L, 316, 316L, 316Ti, 321, 347H, 310S [1]

Production Process:

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

Performance analysis:

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 rust to continue to expand and eventually form holes. This can use paint or oxidation-resistant metal for electroplating to protect the carbon steel surface, but this protective layer is just a thin film, if the protective layer is damaged, the underlying steel will begin to rust again. Whether the stainless steel pipe is corroded is related to the chromium content in the steel. When the chromium content in the steel reaches 12%, a layer of passivated, dense chromium-rich oxide is formed on the surface of the stainless steel pipe in the atmosphere to protect the surface and prevent it Further reoxidized. This oxide layer is extremely thin, through which you can see the natural luster of the steel surface, giving stainless steel a unique surface. If the chromium film is destroyed, the chromium in the steel and the oxygen in the atmosphere regenerate a passive film and continue to play a protective role. In some special environments, stainless steel will also fail due to some local corrosion, but stainless steel and carbon steel will not fail due to uniform corrosion, so the corrosion margin is meaningless for stainless steel pipes.