Review of the first generation of the advanced high-strength steels (AHSS) and their manufacturing procedures

Abstract

The objective of this paper was to present the first generation of Advanced High-Strength Steels (AHSS) and their manufacturing processes, as well as to emphasize their complexity. The AHSSs were created as a solution to reduce the weight of parts and structures in transportation industries (automotive, airplane and truck industry). Regarding the development of the AHSSs, it was divided in three generation. The first generation, to which this paper relates, includes the DP (Dual-Phase), CP (Complex-Phase), TRIP (TRansformation Induced Plasticity) and martensitic steels. Besides implementation of materials with higher strength, lower mass of structures could be achieved by application of materials of a lower density (e.g., aluminum and titanium). Application of the lightweight materials directly results in lowering the structures’ mass, and it positively affects energy efficiency, preservation of the environment and lowering the pollution levels. However, there are still numerous problems and disadvantages, related to application of lightweight materials, primarily with processing (low machineability, deformability, as well as weldability). Besides the processing problems, mentioned materials have higher prices than steel; therefore, development of new steel grades, as well as development of new methods for realizing the higher strength was initiated. It is already well known from the literature that by implementing the selected heat treatment procedures (varying the heating and cooling regimes), the steel properties could be altered. It was thus concluded that combination of the heat treatment and plastic deformation in steel production can result in increasing the steel strength, while simultaneously keeping the good deformability and even weldability.