Which material is better, SPCC cold-rolled steel sheet or Q235B? More corrosion-resistant?

Simply put, cold rolling is a processing method that is carried out on hot-rolled sheets; generally, it involves the sequence of hot rolling – pickling – cold rolling. Cold rolling is a process in which hot-rolled sheets are processed at room temperature; although the sheet temperature rises due to rolling during this process, it is still called cold rolling. Since hot-rolled steel is cold-rolled through continuous cold deformation, it has relatively poor mechanical properties and excessive hardness. It must be annealed to restore its mechanical properties; those that have not been annealed are called hard-rolled coils. Hard-drawn coils are generally used for products that do not require bending or stretching; for coils with a thickness of less than 1.0, it’s possible, with a bit of luck, to bend two or four sides of them. Of course, hot-rolled steel sheets are better than cold-rolled ones.