Stainless steel pipes are hollow steel tubes that are resistant to rust. Stainless steel pipes (Stainless Steel) are hollow, cylindrical steel products used as conduits for transporting fluids. They are widely used in industrial applications such as oil, chemical, medical, food, light industry, and mechanical instrumentation for conveying pipelines and mechanical structural components. Stainless steel pipes are manufactured from acid- and heat-resistant steel billets through processes including heating, piercing, sizing, hot rolling, and cutting.

Classification of stainless steel pipes: There are two basic categories—seamless stainless steel pipes and welded stainless steel pipes (seam pipes). Based on the outer diameter shape, they can be further divided into round pipes and special-shaped pipes. Round pipes are the most widely used, but there are also special-shaped pipes such as square, rectangular, semicircular, hexagonal, equilateral triangular, and octagonal pipes.

All steel pipes designed to withstand fluid pressure must undergo hydrostatic testing and radiographic inspection to verify their pressure resistance and quality. A pipe is considered合格 (qualified) if it does not leak, become wet, or expand under the specified pressure. Some pipes may also require flanging, flaring, or flattening tests in accordance with standards or customer requirements.

Seamless stainless steel pipes, also known as stainless steel seamless tubes, are manufactured by piercing steel ingots or solid billets to form blank tubes, which are then processed through hot rolling, cold rolling, or cold drawing. The specifications of seamless steel pipes are denoted by the outer diameter multiplied by the wall thickness in millimeters. The mechanism of stainless steel’s rust resistance lies in the formation of a dense oxide film by alloying elements, which isolates the metal from oxygen and prevents further oxidation. Therefore, stainless steel is not truly “rust-proof.”