Square pipe according to the production process: hot-rolled seamless square pipe, cold-drawn seamless square pipe, extruded seamless square pipe, welded square pipe.

Among them, the welded square pipe is divided into:

(a) According to the process - arc welded square pipe, resistance welded square pipe (high frequency, low frequency), gas welded square pipe, furnace welded square pipe

(b) According to the weld - straight seam welded square pipe, spiral welded square pipe

Material classification

Square tube according to material: carbon steel square tube, low alloy square tube. Pu carbon steel is divided into: Q195, Q215, Q235, SS400, 20# steel, 45# steel, etc.; Low alloy steels are divided into Q345, 16Mn, Q390, ST52-3, etc.

Production standard classification

Square tube according to production standards: national standard square tube, Japanese standard square tube, imperial square tube, American standard square tube, European standard square tube, non-standard square tube.

Square pipe according to the production process: hot-rolled seamless square pipe, cold-drawn seamless square pipe, extruded seamless square pipe, welded square pipe.

Among them, the welded square pipe is divided into:

(a) According to the process - arc welded square pipe, resistance welded square pipe (high frequency, low frequency), gas welded square pipe, furnace welded square pipe

(b) According to the weld - straight seam welded square pipe, spiral welded square pipe

Material classification

Square tube according to material: carbon steel square tube, low alloy square tube. Pu carbon steel is divided into: Q195, Q215, Q235, SS400, 20# steel, 45# steel, etc.; Low alloy steels are divided into Q345, 16Mn, Q390, ST52-3, etc.

Production standard classification

Square tube according to production standards: national standard square tube, Japanese standard square tube, imperial square tube, American standard square tube, European standard square tube, non-standard square tube.

Cross-section shape classification

Square tubes are classified by cross-sectional shape:

(1) Simple section square tube - square square tube, rectangular square tube

(2) Complex cross-sectional square tube - flower-shaped square tube, open-shaped square tube, corrugated square tube, special-shaped square tube

Surface treatment classification

Square tube according to surface treatment: hot-dip galvanized square tube, electro-galvanized square tube, oiled square tube, pickling square tube

Classification of uses

Square pipes are classified according to their use - square pipes for decoration, square pipes for machine tools and equipment, square pipes for machinery industry, square pipes for chemical industry, square pipes for steel structures, square pipes for shipbuilding, square pipes for automobiles, square pipes for steel beams and columns, square pipes for special purposes

Wall thickness classification

Square tubes are classified by wall thickness – ultra-thick-walled square tubes, thick-walled square pipes and thin-walled square tubes

plasticity

Plasticity refers to the ability of metal materials to produce plastic deformation without damage under load.

hardness

Hardness is a measure of how hard or soft a metal material is. At present, the method of determining hardness in production is commonly used by the press-in hardness method, which is to use a certain geometric indenter to press into the surface of the metal material to be tested under a certain load, and determine its hardness value according to the degree of indentation.

Commonly used methods are Brinell hardness (HB), Rockwell hardness (HRA, HRB, HRC) and Vickers hardness (HV).

fatigue

The strength, plasticity, and hardness discussed above are all indicators of the mechanical properties of metals under static load. In fact, many machine parts are under cyclic loading