(1) The manufacturing process of seamless steel pipe can be divided into several basic categories: hot rolled (extrusion), cold rolled (drawing) and hot expanded steel pipe. (2) According to the manufacturing process, welded pipe can be divided into straight seam welded steel pipe, spiral welded steel pipe, plate coil butt welded steel pipe and welded pipe thermal expansion steel pipe.According to the shape, steel pipes can be divided into: round pipe, square pipe, rectangular pipe, octagonal, hexagonal, D-shaped, pentagonal and other special-shaped steel pipes, complex section steel pipes, double concave steel pipes, five petal quincunx steel pipes, conical steel pipes, corrugated steel pipes, melon seed steel pipes, double convex steel pipes, etc.

Steel pipe can be divided into: steel pipe for pipeline, steel pipe for thermal equipment, steel pipe for mechanical industry, steel pipe for petroleum and geological drilling, container steel pipe, steel pipe for chemical industry, steel pipe for special purpose, etc. Anti corrosion classification of inner wall: folding liquid epoxy coating ipn8710 anti-corrosion and folding fusion bonded epoxy powder anti-corrosion. Classification of external wall anti-corrosion: folding 2PE / 3PE anti-corrosion, single-layer PE anti-corrosion and folding epoxy coal asphalt anti-corrosion. Anti corrosion standard: FBE epoxy powder anti-corrosion shall comply with SY / t0315-2005 technical specification for single layer fusion bonded epoxy powder outer coating of steel pipeline, 2PE / 3PE anti-corrosion shall comply with GB / t23257-2009 technical standard for polyethylene outer coating of buried steel pipeline, anti-corrosion surface rust removal standard: sand blasting on the outer surface of steel pipe shall reach SA2 1 / 2 according to the requirements of GB / t8923-2008, and the depth of anchor grain on the surface of steel pipe shall be 40-100 μ m.The base materials of anti-corrosion steel pipes include spiral pipes, straight seam pipes, seamless pipes, etc. in China, they are widely used in pipeline engineering fields such as long-distance water transmission, petroleum, chemical industry, natural gas, heat, sewage treatment, water source, bridge, steel structure, marine water transmission and piling. In addition to improving the service life of steel pipe through anti-corrosion, it is also reflected in the following aspects: 1. Combine the mechanical strength of steel pipe with the corrosion resistance of plastic; 2. The outer wall coating is more than 2.5mm, resistant to scratch and collision; 3. The friction coefficient of inner wall is small, 0.0081-0.091, reducing energy consumption; 4. The inner wall meets the national health standards; 5. The inner wall is smooth and not easy to scale, with self-cleaning function.