Abstract: The old working process, the conventional die forging technology of 30 CrMnSiA connecting seat and the possibility of superplastic-isothermal precision forging of this part with hydraulic press are analyzed. On the basis of the study on the superfine pretreament of 30CrMnSiA and its structure change during deformation, the selection of deformation temperature, deformation rate, optimum lubricant of super-isothermal precision forging, the determination of die Construction, die material,resistance wire heating apparatus,tonnage of equipment and the the forging experiments of die pressing are also described. Finally, techological process of superplastic-isothermal precision forging is presented. The results of research work show clearly that the new technology has better technological and economical benefits than before.

Key words: superplasticity, isothermal precision forging, deformation temperature, deformation rate, lubricant