Process Design of Aluminum Tailor Heat Treated Blanks

Abstract

In many industrials field, especially in the automotive sector, there is a trend toward lightweight constructions in order to reduce the weight and thereby the CO2 and NOx emissions of the products. An auspicious approach within this context is the substitution of conventional deep drawing steel by precipitation hardenable aluminum alloys. However, based on the low formability, the application for complex stamping parts is challenging. Therefore, at the Institute of Manufacturing Technology, an innovative technology to enhance the forming limit of these lightweight materials was invented. The key idea of the so-called Tailor Heat Treated Blanks (THTB) is optimization of the mechanical properties by local heat treatment before the forming operation. An accurate description of material properties is crucial to predict the forming behavior of tailor heat treated blanks by simulation. Therefore, within in this research project, a holistic approach for the design of the THTB process in dependency of the main influencing parameters is presented and discussed in detail. The capability of the approach for the process development of complex forming operations is demonstrated by a comparison of local blank thickness of a tailgate with the corresponding results from simulation.

Weight reduction in an AA2017 aluminum alloy part through the gas forming process of a blank with a variable thickness

“…Tailored blanks are blanks optimized to locally modify some properties of the sheet metal (thickness, material, etc.). Tailored blanks can be obtained by welding processes [4][5], using customrolled semi-finished products [6][7][8] or heat treated locally [9][10]. To prevent the welding process from causing distortion of the sheet and to partially reinforce the sheet itself, it is possible to add patches where required, using an adhesive bonding operation [11][12][13] before executing the forming process.…”

Effect of selective laser heat treatment on geometrical variation in boron steel components: An experimental investigation

“…Performing local laser heat treatment to enhance formability has been widely shown in case of aluminum alloys in various studies. 5–8 In case of high strength steels, the prospects to enhance formability as well as reinforce strength locally have been investigated thus far. Dual phase steels such as DP 600, DP 1000, and Martensitic steel MS-W 1200 were successfully tested to enhance formability using local laser heat treatment by Neugebauer et al 9 A homogenized zoom-optics was developed to heat treat high strength martensitic steels and complex phase steels by Baumann et al 10 Improvement in formability of the steels using this setup was verified too.…”

A Phenomenological Mechanical Material Model for Precipitation Hardening Aluminium Alloys

“…In addition, numerical descriptions of the heat treatment processes are also used to simulate various manufacturing processes such as welding steels [10], aluminium alloys [11] or induction hardening [12]. Heat treatment simulation of the short-time heat treatments used for tailored heat-treating blanks (THTB) [13,14] and profiles (THTP) for aluminium has not yet been performed. These short-term heat treatments, which locally heat material areas using a laser, are characterized by very high heating rates of several 100 Ks −1 , almost no soaking at peak temperature and subsequent cooling at a few 10 Ks −1 .…”

“…The mechanical properties as a function of the relevant parameters during short-time heat treatment cannot provide both types of models. Material models were also developed for producing tailored heat-treated semi-finished products [13,14]. However, these material models were developed for forming simulations and provide the mechanical properties at room temperature depending on the maximum temperature during heat treatment.…”