Abstract
In recent years, the necessity of the promotion of steel recycling is increasing from the viewpoints of effective usage of resources and restraint of environmental problems. In case steel scrap is recycled, surface cracks occur during hot rolling process, which poses a serious problem. This phenomenon is attributed to Cu. Copper is mixed from steel scrap and Cu in steels is enriched at the steel/scale interface by selective oxidation of Fe. This copper-enriched phase liquefies over 1083°C and penetrates into austenite grain boundaries to cause surface cracking. This cracking is called surface hot shortness due to Cu. To suppress this shortness, addition of Ni is known effective. But removal of Ni is difficult in the current refining process. Therefore, other ways of the suppression are desired. In this research, in order to know the detail of the shortness effects of C and P on the surface hot shortness are investigated.
