31st Hatfield Memorial Lecture: Stainless steels – materials in competition

Abstract

The subject of stainless steels was chosen by the author for this lecture because of Dr Hatfield's pioneering work in this field. He feels, however, that today these steels are under intense competition; the interface between producer and consumer is given particular attention. The importance attached to this aspect of the producers' activities means that the problems under consideration fall as much in the field of market research as of physical metallurgy – it is necessary for suppliers to think as consumers rather than as producers. The competition from other materials with respect to physical properties is not very severe, but that in terms of economic considerations is strong, especially in view of the current overcapacity of the steel industry and the increasing prevalence of trade restrictions. A very brief review is given of contemporary stainless steels, together with a more detailed discussion of duplex austenitic–ferritic steels, which also furnish an example of the need for close cooperation between producers and users – correctly fabricated and used, these steels are superior to conventional austenitic steels in their resistance to stress corrosion, but their properties can easily be destroyed by incorrect treatment. Developments in production technology and machinability are indicated and the need for computerized predictive corrosion programs and data bases is stressed. Finally, some ideas of what can be done to improve the competitive position of stainless steels are mentioned. These include greater use of applications engineers, an emphasis on life-cycle costs, product reliability, and uniform material properties, combining hardware and software, and, above all, joint development work between producers and users of stainless steels.