Stainless Steel (Stainless Steel) is a hollow cylindrical steel bar, the scope of his pipe for conveying fluids, mainly used in petroleum, chemical, medical, food, light industry, machinery and instruments and other industrial pipelines and mechanical components. Stainless steel material used for the acid-and heat-resistant grades of steel billet, after heating, perforation, Sizing, hot-rolled, cut from. 
 The classification of stainless steel: stainless steel seamless pipe and stainless steel welded pipe (seamed pipe) basic two categories. According to pipe diameter and shape can be divided into tube-shaped pipe, round pipe is widely used, but there are some square, rectangular, semi-circular, hexagon, equilateral triangle, octagon shaped steel tubing, etc.. 
 For steel to withstand the fluid pressure and hydraulic pressure test should be carried out to test its pressure-ray detection capability and quality, the provision does not leak under pressure, wet or expansion of qualified, some steel but also according to the standard requirements or demand side curling test, flaring test, flattening test, etc.