Steel treated with a strong deoxidizer to reduce oxygen to a level where no reaction occurs between carbon and oxygen during solidification.
Steel to which sufficient deoxidizing agents have been added to prevent gas evolution during solidification. LAP-A surface defect appearing as a seam caused from folding over hot metal, fins, or sharp corners and then rolling or forging, without welding them into the surface.
The term indicates that the steel has been completely deoxidized by the addition of an agent such as silicon or aluminum, before casting, so that there is practically no evolution of gas during solidification. Killed steels are characterized by a high degree of chemical homogeneity and freedom from porosity.