Analysis of forming titanium welded blanks

• Published in: Computational materials science 2014-11, Vol.94, p.66-72
• Main Authors: Adamus, Janina, Lacki, Piotr
• Format: Article
• Language: English
• Subjects: Applied sciences; Biocompatibility; Blanks; EBW blanks; Exact sciences and technology; Forming; Joining, thermal cutting: metallurgical aspects; Mathematical models; Metals. Metallurgy; Numerical simulation; Sheet-metal forming; Surgical implants; Tailored blanks; Titanium; Titanium base alloys; Weight reduction; Welding
• ISSN: 0927-0256; 1879-0801
• DOI: 10.1016/j.commatsci.2014.01.055

•We analyse forming titanium welded blanks.•We assess the forming possibility of TWBs in a conventional process using rigid tools.•We analyse the effect of the welded blank geometry on the drawn-part depth.•We analyse the influence of forming parameters on the drawn-part quality.•Properly selected holding-down force and frictional conditions can significantly facilitate the forming process. Weight reduction of the structure is a priority issue in the transport industry, especially in aviation. The application of tailor welded blanks (TWB) seems to be the key to success. TWB technology has been successfully used in the automotive industry for steel and aluminium sheets. Titanium in comparison to steel and aluminium has a much more beneficial specific strength (strength-to-weight ratio) therefore titanium tailor welded blanks may be used in the aviation industry where high mechanical strength and low weight of construction are especially essential. There are only a few publications in this field, and simultaneously there are many problems which need to be solved. Although titanium has excellent properties such as high strength, low weight and good corrosion resistance, it is very difficult to manufacture and process. Titanium, especially titanium alloy sheets have poor drawability and low tribological properties. Joints pose additional difficulty in forming titanium welded sheets. In the paper, the experimental and numerical results of sheet-metal forming of titanium welded blanks are presented. Commercially pure titanium Grade 2 (Gr 2) and titanium alloy Grade 5 (Gr 5), which are the most often used in engineering and medicine, are analysed. Forming spherical drawn-parts made of uniform Gr 2 and Gr 5 blanks, and welded Gr 2||Gr 5 blanks are carried out. The blank consists of an internal disc and outer ring which were joined by electron beam welding (EBW). Different configurations of material joints are taken into consideration. Numerical simulations are performed using the PamStamp program based on the finite element method (FEM). The program is dedicated to sheet-metal forming. Stress and strain distribution are analysed. The drawability of the sheets is assessed based on the variations in material thickness before and after deformation (i.e. thinning or thickening), which is compared to the experimental results.