By Raymond E. Brown
Use of iron and steel scrap to produce new steel and ferrous castings, which are vital to the United States for both national security and economic well-being, represents significant energy, environmental, economic, and resource conservation benefits. Direct-reduced iron, pig iron, and iron carbide can be substituted for iron and steel scrap but are usually considered more expensive than scrap. Also, availability of these substitutes on a large scale is limited, and there are certain technical problems associated with the use of some of these substitute materials. However, these scrap alternatives have certain advantages, which include providing iron free of residual elements, such as copper, for use in producing higher quality steel and ferrous castings products. Iron and steel scrap consists of all ferrous materials, either alloyed or unalloyed, containing iron or steel as a principal component that are the waste of industrial production or are objects discarded because of obsolescence, failure, or other reasons. Iron and steel scrap is classified as home scrap (revert, runaround, or internally generated scrap), prompt industrial scrap (waste material resulting from fabrication of new iron and steel products), and obsolete scrap (old scrap consisting of iron or steel products that have been discarded or rejected for various reasons). Purchased scrap consists of the last two classifications. An analysis by the U.S. Bureau of Mines of iron and steel scrap consumption by domestic steel mills revealed that two key trends have emerged during the last 20 years. First, steelmakers have increased their use of electric arc furnaces, which use close to 100% scrap as a charge material to produce raw steel. Second, steel producers have extended their use of continuous casting--a more efficient forming technology than ingot casting--which has increased steel mill processing yields but has left progressively less home scrap available to the mills.
- Table 1.--Salient U.S. iron and steel scrap and pig iron statistics (TXT)