General use steels - Classification and metallurgy

General-purpose steels are used in most common applications.

Despite the wide variety of uses for these steels in all industrial fields, from construction to transport, and from household appliances to packaging, there is a set of characteristics common to all these products, the most important of which is that they are delivered "ready-to-use", in contrast to heat-treated steels, which obtain their characteristics at the user's premises. As a result, the criteria for choosing grades and qualities are essentially based on mechanical properties rather than chemical composition.

The development of general-purpose steels varies according to the field of application. Considerable progress has been made in steelmaking.

Under pressure from user requirements, there are major trends in the evolution of properties such as lightness, weldability and durability with corrosion protection.

The notion of general-purpose steels is a little vague, and only really asserts itself in opposition to special steels, at least in the majority of cases; among the special steels, we essentially note stainless steels, mechanical engineering steels, magnetic sheets and tool steels. Clearly, most of these grades, with the exception of stainless steels, require heat treatment by the user.

In this first article, we deal with the classification and metallurgy of general-purpose steels. In a second article, "General-purpose steels. Properties and products" [M 4 516] , we look at their properties, the main products, and the choice of grades and qualities.