Scrap Quality and Metallurgical Effects Associated with Copper and Tin as Tramp Elements in the Casting Steels

Abstract

The complex property requirements for steels make it essential that there is a thorough understanding of the influence of tramp elements on their properties. Surface aspects, metallurgical structure, mechanical properties (toughness, tensile strength hardness …) and weldability are some examples of requirements for quality steels in correlation with these residual elements. An increased content of residual elements such as Cu, Ni, Sb, Sn, As… may deteriorate the final properties of steels.
These elements are introduced to steel using steel scrap in the steelmaking process. The recycled scrap can contain considerable quantities of impurities. For this reason the control of ferrous scrap is necessary in order to preserve the recycling rate at the current high level without sacrificing steel quality.
In this paper we discuss about copper and tin as particularly tramp elements in respect to their influence on the properties of the engineering steels and structure. For a lot of casting steels, we analyze these residual elements in respect to the tolerable contents. The possible synergic relations between other elements and these impurities are also considered. The sources and the effects of the residual elements were discussed as far as possible, in order to obtain accurate answers for practical situations.