Trends in the global development of automotive sheet steels

The paper provides an overview of current trends in the global development of automotive sheet steel. The review includes a study of the WorldAutoSteel Program, which unites 18 major steel producers and provides global information on automotive sheet steel applications. It was found that, given the rapid development of hybrid and electric vehicles, the WorldAutoSteel program objectives were: identifying promising power units and their impact on vehicle architecture; investigating the possibility of using steels for future vehicles; investigating the potential for reducing vehicle weight using AHSS, new technological processes, and automated design optimization; formulating requirements for new steel grades based on the analysis of loads caused in the design of an electric vehicle. The advantages of AHSS are briefly discussed using the example of dual-phase automotive steel (DP). DP600 is a low-carbon cold stamping steel that hardens during shaping and has two main phases in its microstructure: ferritic (a soft, plastic phase that determines the low yield strength of the two-phase steel) and martensitic (a hard phase that imparts the necessary strength to this steel). The microstructure of the two-phase steel may also contain a bainitic component and traces of residual austenite. In the literature, such steels are called two-phase ferritic-martensitic, in contrast to the common ferritic-pearlite, ferritic-bainitic, ferritic-austenitic, austenitic-martesitic and other two-phase steels. Two-phase ferritic-martensitic steels (DPFS) are essentially a composite material in which high-strength martensite islands are surrounded by a plastic ferritic matrix. Due to this structural design, they have high plasticity and increased strength.