CTS TUBES The knowledge of tubes and pipes First, the classification of the pipe 1, according to the production method of classification (1) seamless - hot-rolled tubes, cold-rolled, cold drawn tubes, squeeze tubes, pipe jacking (2) pipe (A) according to process sub - arc welded pipe, ERW pipe (high frequency, low frequency), gas pipe, stove pipe (B) by the weld points - Longitudinal spiral welded pipe 2, according to a cross-sectional shape classification (1) simple section steel - round pipe, square pipe, oval pipe, steel triangular, hexagonal steel, diamond steel, octagonal steel, steel semi-circle, the other (2) section steel complex - equilateral hexagonal steel pipe, five plum-shaped pipe, steel double convex, double concave steel, oval-shaped steel conical pipe, corrugated steel pipe, steel case, other 3, according to the thickness classification Thin-walled steel pipe, thick-walled steel pipe 4. By Application With steel pipe, steel pipe the