New Technology for the Production of Magnesium Strips and Sheets

The growing significance of the material magnesium is closely associated with the progressive development in the field of automotive lightweight construction. The announcement of the VW AG of constructing an one-litre-automobile can be deemed to be a proof of the actuality of research and development in the field of magnesium alloy processing. That automobile, whose frame structure is widely made of magnesium, shall be mass-produced before end of 2010 1 . The material magnesium does not compete only with other metallic materials, also in particular with novel material concepts of the plastics industry. In this connection the better recyclebility and therefore the better environmental compatibility compared to the plastics is an essential advantage of magnesium. The production of semi-finished Mg-parts with continuously working mills leads to substantial advantages compared to conventional processes due to the omission of production steps. Therefore, many different continuous strip casting processes have been an object of development efforts. The strip casting process for the production of wide strips has already been developed in the aluminium industry; however, the transfer from the aluminium materials to the magnesium materials is difficult. There are open problems regarding the systems engineering such as the tundish and tip construction as well as the material itself. For several years many development institutes and industrial companies have been working on the application of strip casting processes for the processing of magnesium wrought alloys. In cooperation with the MgF Magnesium Flachprodukte GmbH the twin-roll-casting technology has been developed to series-production readiness. It enables a continuous production of near-net shape strips compared to the conventional light metal casting. So far the twin-rollcasting technology has successfully been tested on the pilot plant in Freiberg with the alloys AZ21 and AZ31 2, 3, 4 .