Development of Low Cost Production Techniques for Titanium Parts

Recently, applications of titanium alloys to aircraft structures are increasing because of its good material properties and galvanic/thermal expansion compatibility with CFRP. However, manufacturing costs of titanium parts are high due to its material cost, especially thick materials (plates, extrusions and forgings), and machining cost from them. On the other hand, welding process could realize near net shape products and lower manufacturing cost. In addition, the state of the art laser welding has improved some problems which conventional welding methods have. For example laser welding has less deformation compared to other welding methods (e.g. Gas Tungsten Arc Welding). And laser welding has less limitation in parts size compared to Electron Beam Welding limited to vacuum chamber size. This paper describes development of low cost production techniques for titanium parts using this laser welding, as below.

(1)   Appropriate laser welding parameters for butt and fillet joints were evaluated. Mechanical properties of both joints were also evaluated.

(2)   Representative parts, which were simulated airplane fuselage frames, were successfully manufactured. With near net shape process, we confirm potential 30% cost reduction compared to conventional technique.

This work was conducted from 2008 to 2012 as a part of the project, “Aerospace Industry Innovation Program-Advanced Material & Process Development for Next-Generation Aircraft Structures” under the contract with SOKEIZAI Center, founded by Ministry of Economy, Trade and Industry (METI) of Japan.