The soaring pursuit for weight reduction of car body parts originates from the need for efficient fuel consumption and for reduced carbon dioxide (CO2) emissions, respectively. Aluminium alloys qualify for light weight constructions due to their low density at comparatively high strength. The formability of aluminium alloys, however, is relatively poor. In this respect, innovative technologies for aluminium sheet forming have to be developed. In this paper, the application of tailored heat treated blanks (THTB) for fast hardenable aluminium alloys of the 6000-series is presented. THTB are locally heat treated aluminium blanks exhibiting a specific strength pattern optimised to the forming operation. By locally heat treating the flange area of the blank, the initial true stress in the forming zone is reduced resulting in lower stresses in the force-transferring areas of the blank. Based on material and lubricant related investigations, process boundaries for the THTB design are derived. In this context, the impact of the local heat treatment on the mechanical properties of the fast-hardenable alloy AA6181PX was studied yielding an initial reduction of the yield strength at a maximum temperature of 200 deg C, a maximum reduction of the yield strength at a maximum temperature of 400 deg C and a minimum of the uniform elongation between 290 deg C and 350 deg C. The minimum of the uniform elongation was found to be caused by the appearance of beta(') precipitations. The impact of the local heat treatment on the dry lubricant (Multidraw Drylube E1) was analysed yielding that the lubrication ability can be maintained for a maximum temperature of up to 250 deg C and the degreasability for a maximum temperature of up to 280 deg C. Moreover, to identify the most appropriate strength distribution and so the relevant heat treatment parameters of a THTB, an inverse, finite element (FE)-based approach for the design of THTB allowing effective and efficient THTB engineering cycles is introduced.
Tailored heat treated blanks applied on car body parts under quasi-series conditions
Wärmebehandelte Blechformteile zur Herstellung von Fahrzeug-Karosserieteilen unter seriennahen Bedingungen
International Journal of Microstructure and Materials Properties (Online) ; 4 , 5/6 ; 525-533
2009
9 Seiten, 5 Bilder, 1 Tabelle, 7 Quellen
Aufsatz (Zeitschrift)
Englisch
Blechformteil , Wärmebehandlung (Materialbearbeitung) , Aluminiumsiliciummagnesiumlegierung , Karosseriekomponente , Formbarkeit , aushärtbare Legierung , wirkliche Verformung , Umformzone , Tiefziehblech , Tiefziehfähigkeit , Tiefziehen , Feststoffschmierung , Festschmierstoff , Verfahrensfenster , Streckgrenze , Temperaturbereich , Dehnung , Ausscheidungsprodukt , Festigkeitsverlust , Schmiereigenschaft , Entfetten , Prozessoptimierung , Prozessentwicklung
Seriennahe Auslegung von Aluminum Tailored Heat Treated Blanks
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