Can a simple heat treatment help to save Detroit?

Abstract

Laws passed and regulations approved by the Congress of the USA in recent years require new automobiles in the USA to conform to standards of NO_x emission, impact resistance, and fuel consumption which will test to the limit the technological and manufacturing resourcefulness of the American automobile industry. Radical changes will have to be made in the materials used. Changes in engine design and a reduction in the size of the automobiles will be insufficient. Steel is the cheapest acceptable material for many components, but steel will retain its position in the automobile market only if it can be made much stronger (thus reducing the section thickness and weight) without impairing its ductility, formability, weldability, and low cost. New steels for automobiles have been developed from the laboratory to full-scale production with astonishing speed in the last three years. The most promising of the new steels – ‘dual-phase steels’ – have more than twice the strength of traditional automobile sheet and can be formed using existing presses and dies. An essential step in the processing of this remarkable class of steels is a simple, but unconventional, heat treatment. The history, physical metallurgy, application, and future development of dual-phase steels are reviewed and discussed.