ABSTRACT

This chapter describes the steps in the steelmaking process from a metallurgical point of view and the method by which steelmakers can design alloys of the desired quality. The steps considered are the treatment of the melted steel, the effect of alloying additions, and the rolling practice. From the steelmakers' point of view, economy is a fourth requirement, which undoubtedly has stimulated many of the developments in steel metallurgy that have resulted in modern alloys and their associated technologies. Some alloys can be treated to have yield strengths of the order of 1500 MPa, but these are fully martensitic, with high carbon contents, not designed for fabrication by welding. The iron-carbon phase diagram shows the different phases that appear in plain carbon steels as a function of temperature and carbon content. For most applications, fully killed steels are required and these steels have a relatively low process yield, due to the cavity formed as a result of shrinkage during solidification.