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The current study is a trial to validate the possibility of using high strength stainless steels, for automotive structural parts. The studied material is a nitrogen-alloyed, high manganese austenitic stainless steel, 204M. The material behavior was compared to that of the conventional metastable austenitic stainless steel 301L. This study shows that the mechanical properties and the formability are very similar for these two steels. A feasibility study for the production of an engine cradel for a medium size passenger car with both stamping and hydroforming was conducted. Lower part weight can be achieved by using thinner gauges than for the conventional carbon steel part. The stainless steel part also showed the potential for higher collapse resistance. These features reveal that high strength stainless steel with high ductility has great potential for use in automotive structural design.

TRIP (TRansformation Induced Plasticity) steels have been studied frequently because of its superior strength and ductility. The high values of tensile strength and elongation are mainly attributed to the strain induce martensite transformation (SIMT) phenomena of retained austenite. Because of the excellent tensile property combination, TRIP steels have many advantages when the steels are used for automotive applications. To produce as-hot-rolled TRIP steels with better microstructure and mechanical properties, an appropriate chemical composition together with the exact control of cooling in run-out table is major parameter. A 3-step cooling pattern in run-out table (ROT) should be employed to secure sufficient amount of ferrite and resultant carbon enrichment in untransformed austenite. Effective carbon enrichment in untransformed austenite is very important to increase stability of austenite in lower temperature region.