Abstract:A new technology of die forming, with a metallic jacket intercalated heat insulating sheet to envelope the hot metallic work-piece and keep its temperature to be decreased only a little, has been developed and used to produce large work-pieces. The results showed that this technology could obtain ideal forging temperature, reduce forging loads, fine crystal grains, eliminate forging cracks, improve the properties of the forged work-piece and lengthen the service life of the mould. For the first time, some large precise forged work-pieces of unmanageable metals are produced in China.

Key words: compound jacket  die forging  aluminium  titanium steel