Titanium and Titanium Alloys - Sheet Metal Working

Background

Annealed or solution treated sheet can be cold formed by most of the conventional sheet metal working operations. It is advantageous to carry out the work relatively slowly although recent experience suggests that deformation speeds similar to those used with type 409 stainless steel are acceptable. While much sheet forming of commercially pure titanium is carried out successfully with bare metal, the process can sometimes be assisted by the use of lubricants. Solid lubricants such as soap, molybdenum disulphide or graphite are preferable to mineral oils and greases; a resinous paint coating or thin polyethylene or polypropylene sheeting will help avoid galling and pick-up of titanium on the die.

Ductility is increased at moderately elevated temperatures. If both workpiece and dies are heated, the metal can be deformed slowly, and the operation tends towards creep forming. Complex shapes with quite sharp bend radii can be obtained with the commercially pure grades, while medium strength alloys require temperatures up to around 650-700°C. At these temperatures care must be taken to guard against contamination, particularly by hydrogen, during any prolonged heating. In creep forming, coatings are often used to reduce oxidation as much as possible. Any thin superficial oxide and oxygen rich layers that are formed should subsequently be removed since they may lead to cracking and failure in service.

Source: Materials Information Service – The Selection and Use of Titanium, A design Guide

For more information on this source please visit The Institute of Materials, Minerals and Mining.