Zusammenfassung
Intermediate annealing is a widely used process to recover formability in multi-stage deep drawing of austenitic stainless steel sheets. A special ability of metastable austenitic stainless steel is the so called strain-induced martensite formation, which causes the TRIP-effect (TRansformation Induced Plasticity). Major issues of intermediate annealing in serial production processes are long annealing times and high costs for annealing equipment and consumed heating energy. One suggestion for optimization of this process made in this paper is to anneal austenitic material only in regions of the part where it is required and to use suitable annealing parameters. This annealing parameters need to be optimized to requirements of follow-up forming processes. Therefor, basic intermediate annealing experiments were accomplished for austenitic grade EN 1.4301 within temperature range of 100-1100°C. Measurements of mechanical properties by uniaxial tensile tests, martensite contents measured by Feritscope and micrographs are showing the development of martensite reversion as well as reconstitution of austenitic phase. Especially 400°C, 600°C and 1000°C were identified as most interesting annealing temperature levels due to formation of carbides and recrystallization. This knowledge can be used as base for further local heat treatment concepts and may enhance, simplify and save costs of intermediate annealing process of deep draw components made of stainless steel.
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