Introduction to hot working of steel for steel structures

Hot processing can destroy the structure of the steel, make the grain of the metal finer, but also under high temperature and pressure pressed in the billet pores, cracks and other defects, improve the mechanical properties of steel. The strength, plasticity, toughness and weldability of hot emulsion sheet and thin wall steel are better than those of thick plate and thick wall steel because of more rolling times and larger compression ratio. This is why the strength of steel is grouped according to plate thickness.

Hot processing makes the metal grains form fiber structure along the deformation direction, so that the performance of steel along the rolling direction (longitudinal) is better than that of the vertical rolling direction (transverse), even if its anisotropy increases. Therefore, for steel plate parts, tensile and cold bending tests should be carried out along the transverse cutting specimens. Non-metallic inclusions such as sulfide and oxide in steel are pressed into sheets after rolling. For thick steel plates with relatively small rolling compression, the sheets cannot be welded together and there will be stratification. Lamination deteriorates the performance of steel plate tensile along the thickness direction, and lamellar tearing may occur (as shown in Figure 2.2) when the welding joint has a tensile effect along the thickness direction (including the constrained tensile stress caused by welding), which should be paid attention to.