ASTM A36 Rectangular Steel Tube

 

A36 steel pipe is a type of carbon structural steel pipe used for welding and bolted metal structures in industrial and civil construction, as well as bridge construction. ASTM A36 rectangular pipes are also used for manufacturing products and components for general construction and mechanical engineering purposes.

A36 Rectangular Metal Tubing Specification

Product Type	ASTM A36 square Tube
Specification	OD15*15mm-400*400mm
OD	20mm*10mm - 400mm*300mm,
Wall Thickness	0.8~12.0mm
Standard	GB, BS, ASTM
Steel material	Q195. Q215, Q235, Q345
Size length	11′ thru 24′
Surface Treatment	Bared, Black Painted (varnish coating), Galvanized, With Oiled, 3 PE, FBE, corrosion resistant coating
Section Shape	Square and rectangular
Package	Bundle, In Bulk, Bags square galvanised steel hollow section tube, Clients' Requirements

A36 Rectangular Steel Pipe

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

How to Identify Inferior Quality A36 Rectangular Pipes

1. Inferior rectangular pipes are prone to folding. Folding refers to various folds formed on the surface of the rectangular pipe, which often extend longitudinally throughout the entire product. The reason for the occurrence of folding is that inferior manufacturers pursue high efficiency, leading to excessive reduction, resulting in ears, which then cause folding during the next rolling process. Products with folds are prone to cracking after bending, resulting in a significant decrease in the strength of the steel.

2. Inferior rectangular pipes often exhibit a pitted surface. Pitting is a defect caused by severe groove wear, resulting in irregularities on the surface of the steel. Because inferior rectangular pipe manufacturers often pursue profit, the rolling groove is frequently out of specification.

3. The surface of inferior rectangular pipes is prone to scarring. There are two reasons: (1) the material of inferior rectangular pipes is uneven, with many impurities. (2) Inferior manufacturers have rudimentary equipment and are prone to steel sticking, resulting in these impurities.

4. The surface of inferior materials is prone to cracking due to the high porosity of the billet, which leads to cracks during cooling due to thermal stress. These cracks become evident after rolling.

5. Inferior rectangular pipes are susceptible to scratches because manufacturers have rudimentary equipment, leading to burrs that scratch the surface of the steel. Deep scratches reduce the strength of the steel.

6. Inferior rectangular pipes lack metallic luster due to two reasons: first, their billets are rough. Second, the rolling temperature of inferior materials is not standardized; they gauge the steel temperature visually, making it impossible to roll according to the specified austenite region, resulting in substandard performance.

7. The ribs of inferior rectangular pipes are thin and low, often resulting in insufficient filling.

8. The cross-section of inferior rectangular pipes is elliptical because manufacturers, in order to save materials, excessively reduce the thickness of the first two passes before the final pass. This greatly reduces the strength of the threaded steel and does not conform to the standard dimensions of threaded steel.

9. High-quality steel has a uniform composition, and the tonnage of the cold shear machine is high, resulting in smooth and neat end faces. In contrast, inferior materials often exhibit meat loss on the end faces, i.e., unevenness, and lack metallic luster.

10. Inferior rectangular pipes have a high impurity content, resulting in low steel density and significant dimensional deviations. Without a vernier caliper, it is possible to weigh and verify them.

11. The inner diameter size of inferior rectangular pipes fluctuates significantly.

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