Development of existing Advanced High Strength Steels (AHSS) is aimed at improving their uniformity and strain hardening capability so that they are suitable for existing part shapes and forming techniques. Steels of even greater strength (Ultra High Strength Steels) are also being used,but because of their small elongation are limited to parts of simple shape. In this paper,recent activities in the field are reviewed in the following way: (1) Applications and recent research in AHSS. (2)Part and process designers rely heavily on advanced numerical modeling; this requires accurate knowledge of material behaviour particularly in terms of stress strain data,rate sensitivity,fatigue and thermal response. Efficient methods of gathering this information are required. (3)New materials generate new challenges in accommodating rapid die wear,die distortion and greater variability in incoming material. Reduced strain hardening potential must be overcome by improved design. (4)Higher strength has traditionally been obtained by grain refinement,solute strengthening,particle dispersion and ageing. Attention is now being given to multi-phase structures and the application of multi-scale modeling techniques to understand their behaviour in conjunction with microstructural investigations down to nano levels.
展开▼
