Advantages：

The forming speed is fast, the output is high, and it can be made into a variety of cross-sectional forms to meet the needs of the use conditions. Cold rolling can cause a large plastic deformation of the steel, thereby increasing the yield point of the steel. Hot rolling can destroy the casting structure of the steel ingot, refine the grains of the steel, and eliminate the defects of the microstructure so that the steel structure is dense and the mechanical properties are improved.

Disadvantages

1）Metal delamination – When the steel pipe is cold-rolled, the non-metallic inclusions (mainly sulfides oxides, and silicates) inside the steel are pressed into thin sheets, and delamination (interlayer) occurs. Delamination greatly deteriorates the mechanical properties of steel along the thickness direction and may cause interlaminar tearing when the weld expands.

2）Uneven wall thickness—it is well known that metals expand with heat and contract with cold. Even if the cold-rolled steel pipe meets the standard in length and thickness at the end of rolling, there will still be a certain negative difference after cooling. The larger the value, the worse the uniformity of the wall thickness. Therefore, the wall thickness, length, straightness, and ellipticity of cold-rolled seamless steel pipes cannot be too accurate.

3）Residual stress – Due to uneven cooling, steel pipes of various cross-sections have residual stress. The larger the cross-sectional size of the steel, the greater the residual stress, which has a certain impact on performance under the action of external force. For example, it may have adverse effects on deformation, stability, fatigue resistance, etc.

4）Residual stress – Due to uneven cooling, steel pipes of various cross-sections have residual stress. The larger the cross-sectional size of the steel, the greater the residual stress, which has a certain impact on performance under the action of external force. For example, it may have adverse effects on deformation, stability, fatigue resistance, etc.