General use steels - Properties and products

Article [M 4 515] describes the manufacturing conditions and metallurgical basis for general-purpose steels. The present article deals with the properties of different steels. Properties include processing properties, such as formability, weldability, machinability and forgeability, and service properties, which guarantee service life. Among the latter, the main ones are not only yield strength and strength, which are used to dimension structures and parts, but also fracture resistance parameters, whether ductile, brittle, fatigue or creep, as well as corrosion resistance.

The various product categories described are heavy plates, thin plates, wire rod, sections, bars, concrete products, rails and semi-finished products. The section on thin plates is particularly detailed because of the proliferation of grades, in response to the demands of the automotive industry for lighter, more impact-resistant vehicles. This multiplication is due to the adaptation of properties to the shape of the parts, then to their behavior in service. The evolution of ferritic grades towards higher properties through the addition of microalloys or alloying elements is described, followed by the development of multi-phase grades: dual-phase, TRIP, complex-phase and martensitic steels. Finally, the rules governing the choice of grades and qualities for heavy plate are outlined.

At the end of the article, readers will find a glossary of important terms, as well as a table of notations and anonyms used throughout the article.