Advantages and disadvantages of hot rolled precision steel tubes

For precision steel tubes, hot rolling is compared to cold rolling, which is rolled below the recrystallization temperature, while hot rolling is rolled above the recrystallization temperature.

Advantages of hot rolled precision steel tube:

It can destroy the casting structure of steel ingot, refine the grain of steel, and eliminate the defects of microstructure, so as to improve the microstructure and mechanical properties of steel. This improvement is mainly reflected in the rolling direction, so that the steel is no longer isotropic to some extent; Bubbles, cracks and looseness formed during pouring can also be welded under high temperature and pressure.

Precision steel pipes finished in Haihao Group

Precision steel pipes finished in Haihao Group

Disadvantages of hot rolled precision steel tube:

1.After hot rolling, the non-metallic inclusions (mainly vulcanization and oxides, as well as silicates) inside the steel are pressed into thin sheets and layered.Lamination greatly deteriorates the tensile properties of the steel along the thickness direction, and interlaminar tearing may occur when the weld shrinks.The local strain induced by weld contraction often reaches several times of the yield point strain, which is much larger than that caused by load.

2.Residual stress caused by uneven cooling.The residual stress is the internal self-phase equilibrium stress in the absence of external force. All kinds of hot rolled section steel have such residual stress. The larger the section size of general section steel, the greater the residual stress.Although the residual stress is self-equilibrium, it has a certain effect on the performance of steel members under the action of external forces. Such as deformation, stability, anti – fatigue and other aspects may have adverse effects.

3.It is difficult to control the thickness and side width of hot rolled steel products.We are familiar with thermal expansion and cold contraction. Even though the length and thickness are up to standard after hot rolling at the beginning, there will still be a certain negative difference after cooling. The wider the negative difference edge is, the more obvious the thickness will be.So for large sizes, you can’t be too precise about the width, thickness, length, Angle, and edge lines of the steel.