Development of a Columbium-Phosphorus High-Strength Cold-Rolled Steel

As a result of both laboratory and mill studies, a high-strength cold-rolled sheet steel containing columbium and phosphorus was developed. The chemistry and processing schedule are critically balanced to produce a steel with yield strength levels of at least 40 ksi, with good spot weldability and acceptable low surface contaminants for good paintability. Because of a limited alloy content, these steels can be produced as wide, light gage strip with surface quality suitable for automotive outer body panels.