Ordinary medium and thick steel plate S550 steel is a kind of deoxidized steel. The oxygen content of the steel liquid is relatively high, and a lot of gas will be produced during the production process to make the steel liquid boil, so it is also called boiling steel. Advantages: this kind of steel plate has smooth surface, good quality and easy processing. Because this kind of steel plate has no concentrated shrinkage cavity, the amount of deoxidizer is very small and the price is lower than other steel plates.
Low welding crack sensitivity high-strength steel plate, today mainly introduces Q620CF, with three grades C, D, E. The grades of low-welding crack sensitivity high-strength steel plate: Q460CFC, Q460CFD, Q460CFE, Q500CFC, Q500CFD, Q500CFE, Q550CFC, Q550CFD , Q550CFE, Q620CFC, Q620CFD, Q620CFE, Q690CFC, Q690CFD, Q690CFE, S550 steel, Q800CFE. It is mainly used for the production of hydropower penstocks, construction machinery, railway vehicles, bridges, high-rise and large-span buildings that require high weldability.
Most common S550 steel steel plates are rolled by hot rolling or controlled rolling. Compared with the general hot rolling process, the advantages of controlled rolling are: the strength and low temperature toughness of steel plates are greatly improved by controlled rolling to refine grains. In addition, the controlled rolling process can give full play to the role of Microalloying Elements Nb, V and Ti, not only play a role of precipitation strengthening, but also refine the grains, and improve the toughness of the rolled S550 steel steel plates.