Classification of seamless rectangular tubes

1. Classification by production method
(1) Seamless pipes - hot-rolled, cold-rolled, cold-drawn, extruded, and jacked pipes
(2) Welded pipe
(a) Classified by process - arc welded pipe, resistance welded pipe (high frequency, low frequency), gas welded pipe, furnace welded pipe
(b) Classified by weld seam - straight seam welded pipe, spiral welded pipe
2. Classification by section shape
(1) Simple cross-section steel pipes - circular steel pipes, square steel pipes, elliptical steel pipes, triangular steel pipes, hexagonal steel pipes, diamond steel pipes, octagonal steel pipes, semi circular steel circles, others
(2) Complex cross-section steel pipes - unequal hexagonal steel pipes, five petal plum blossom shaped steel pipes, double convex steel pipes, double concave steel pipes, melon shaped steel pipes, conical steel pipes, corrugated steel pipes, watch case steel pipes, others
3. Classification by wall thickness
Thin walled steel pipes, thick walled steel pipes
4. Classification by purpose
Steel pipes for pipelines, thermal equipment, mechanical industry, petroleum and geological drilling, container, chemical industry, special purpose, and others