1. Seamless Steel Pipe
Seamless steel pipe is a primary method for manufacturing high-quality steel pipe. The steel can be directly processed into pipes without any welding. Common seamless steel pipe grades include 20#, 45#, and 16Mn, with specifications ranging from 6mm to 720mm.
2. Welded Steel Pipe
Welded steel pipe is made by hot-rolling or cold-rolling steel plates and then welding them. Common welded steel pipe grades include Q235B, Q345B, and Q345C, with specifications ranging from 10mm to 630mm.
3. Square Pipe
Square pipe is a hollow steel pipe with a square cross-section and a square shape. Common square pipe grades include Q195, Q215, Q235, and Q345, with specifications ranging from 20*20mm to 500*500mm.
4. Rectangular Tube
Rectangular tube is a steel tube with a hollow, rectangular cross-section and a rectangular shape. Commonly used grades include Q195, Q215, Q235, and Q345, with sizes ranging from 20*30mm to 600*800mm.
5. Other Grades
In addition to the common steel tube grades and specifications listed above, there are many other types of steel tube, including stainless steel, alloy steel, and special steel. These types of steel tube are often used in specific industrial fields, such as chemical, aviation, and aerospace.