Interactions between REM and harmful impurities in Cr-Ni steels

1. The small additions (up to 0.15%) of REM to commercial steels with harmful impurities interact only with oxygen and sulfur (and also selenium if it is present). 2. At elevated concentrations (tenths of a percent) the REM may form compounds not only with oxygen and sulfur but also with phosphorus, arsenic, antimony, lead, bismuth, tin, copper, nickel, and iron. The possibility of a particular compound being formed and the quantity depend on the concentrations of REM, harmful impurities, and the basic elements of the metal. 3. The activity of REM with respect to elements entering into the composition of the steel or alloy agrees with the position of the element in the periodic table and diminishes in the following order: groups VIB, VB, IVB, IIIB, IB, VIII.