Hot Deep Drawing Processing of Titanium Sheet Metal Parts for High Temperature Applications

Abstract

Hot deep drawing (HDD) is an innovative promising compromise to reduce costs by saving production time and to reduce the expenses for surface treatment. Parts made by HDD provide a high accuracy and constant wall thickness suitable for automated industrial assembly. In this paper, the behavior of one near-α titanium alloy, used to manufacture the components of exhaust systems, are observed during HDD. It aims at improving the mechanical properties of the formed component by means of an integrated annealing to prevent, or at least minimize, the spring back behavior. For this purpose, the parameters of HDD followed by the so-called creep relaxation period are optimized. They are: heating time, forming temperature, creep strain, strain rate, and relaxation time. Based on a statistical experimental design, the experimental procedure are conducted by utilizing a forming dilatometer. The results reveal a considerable impact of relaxation time on the material behavior. In addition, variation of the strain rate has also an effect on the considered outputs. Regarding the aforementioned challenges, a set of parameter is suggested, with which all the expected drawbacks can be diminished.

Tensile properties of α-titanium alloys at elevated temperatures

“…An uniaxial tensile test was conducted at seven temperature levels: Room temperature (RT), 400, 500, 600, 650, 700 and 800 °C. The temperature of 650 °C was chosen in consideration of results published in works of [6], who assumed that this temperature level is outside the critical α-case formation. Figure 2 depicts both types of the used tensile specimens.…”

“…On the other hand, heating titanium sheets to a higher temperature causes the formation of detrimental α-case in the surface layer by diffusion, which affects the late fatigue properties of the part tremendous. This has been studied in [6] and a statement about the best forming temperature for some αtitanium alloys were made. Figure 1 shows an α-case surface layer of the sheet metal depending on to the forming temperature.…”

Comparative Analysis of Finite Element Formulations for Simulating Hot Forming of Ti-6Al-4V Aerospace Components

“…The HF process, pivotal in shaping these complex components, leverages elevated temperatures to enhance material ductility up to approximately 60%, facilitating the deformation of Ti-6Al-4V into intricate geometries without compromising its inherent strength and lightweight characteristics [6,7]. This process is instrumental in the aerospace industry, where the demand for materials combining high strength-to-weight ratios and corrosion resistance is paramount.…”