Abstract
Metastable austenite stainless steel AISI 316L is sensitive to cold deformation, where transformation from austenite to martensite occurred. The bending deformation as the formation process leads to tensile and compression troughout the thickness of the billet. Tensile testing of the specimen causes differences in the true stress-strain along the contraction neck prior to fracture as well. The aim of the paper is to find correlation between microhardness as brief inspection parameters and extension of martensitic transformation. The total equivalent plastic strain extend diagram obtained by numerical simulation of bending was compared with tensile true stress-strain diagram. Results show very good correlation between hardness, true strain and martesite content. Therefore, one can conclude that by hardness measurement, it is possible to measure the level of equivalent plastic strain until ultimate tensile stress as a linear correlation between hardness, true strain and martesite content.
Kurzfassung
Metastabiler austenitischer rostfreier Stahl AISI 316L ist empfindlich gegenüber Kaltverformung. Die Kaltverformung ist verbunden mit einer Phasenumwandlung von Austenit in Martensit. Das Biegen als Gestaltungsprozess führt zu Zug- und Druckverformung über die Balkendicke. Der Zugversuch führt zu Unterschieden in der wahren Dehnung entlang der Einschnürung am Probenhals sowohl vor, als auch während des Bruchs. Ziel der vorliegenden Arbeit ist eine Korrelation zwischen der Mikrohärte als Parameter der Erstinspektion und der Martensitumwandlung zu finden. Das Diagramm der totalen plastischen Vergleichsdehnung wurde für Biegung über die numerische Simulation ermittelt und mit dem wahren Spannungs-Dehnungs-Diagramm für Zug verglichen. Die Ergebnisse zeigen eine sehr gute Korrelation zwischen Härte, wahrer Dehnung und Martensitgehalt. Daher kann geschlussfolgert werden, dass es durch Härtemessung möglich ist, die Höhe der plastischen Vergleichsdehnung bis zur Zugfestigkeit über die lineare Korrelation zwischen Härte, wahrer Dehnung und Martensitgehalt zu bestimmen.
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