Seamless square tube is a type of circular, square, and rectangular steel with a hollow cross-section and no seams around it. Seamless steel pipes have a hollow cross-section and are widely used as pipelines for transporting fluids, such as oil, natural gas, gas, water, and certain solid materials.Seamless square tube classification:

1.Classified by material: ordinary carbon steel, high-quality carbon steel;

2. Classified by purpose: 

(A) Structural steel pipes for bridges;

(B) High pressure seamless steel pipes for boilers;

(C) High pressure seamless steel pipes for chemical and electrical purposes;

(D) Petroleum drilling rods, diamond drills, specialized reamers, etc. used for petroleum geological drilling.

(E) Seamless steel pipes made of carbon steel alloy steel and stainless acid resistant steel for ships.

3. According to the connection method, it can be divided into welded square pipes and non welded square pipes.

4. According to the shape of the cross-section, it can be divided into equal cross-section and variable cross-section.

5. According to wall thickness, it is divided into thin-walled square tubes, ordinary square tubes, thickened square tubes, and extra thick square tubes.

6. Classified by purpose - General purpose angle iron is ordinary angle iron, while special purpose angle iron is special angle iron such as stainless steel angle iron, etc.

7. According to different materials, it can be divided into many types:

(1) Hot rolled flat steel, also known as hot rolled round flat steel or round flat material. It refers to a flat product made by directly cold rolling a round bar after heating.