We are SINO EAST. We are big manufacturer in China. Now I introduce the knowledge of pipes for you. 

1, according to the production method of classification (1) seamless - hot-rolled pipes, cold-rolled, cold drawn tubes, extruded tube, top tube (2) Pipe (a) by technology - arc welded pipe, ERW pipes (High-frequency, low frequency), gas pipe, stove pipe (b) by weld points - longitudinally welded pipes, spiral welded pipe

2, according to cross-sectional shape classification (1) simple section steel - round pipe, square pipe, oval steel, triangular steel, hexagonal steel, diamond steel, octagonal steel, steel semi-circle, the other (2) complex section steel - steel equilateral hexagons, five plum-shaped steel, steel double convex, double concave steel, oval-shaped steel, conical steel pipe, corrugated steel pipe, steel case, other

3, according to the wall thickness of classification - thin-walled steel pipe

4, by use classification - with steel pipe, steel pipe thermal equipment, machinery and industrial steel, petroleum, geological drilling steel, container steel, chemical industry with steel pipes, special-purpose steel pipes, other The more you know, the better you can buy the pipes.