Process for producing a fine-grained workpiece from a nickel-based superalloy

摘要

A fine-grained workpiece having improved mechanical properties is produced from a nickel-based superalloy by two-part forging, a blank being converted, in a first isothermal hot-forming step (curve b) above the solution-annealing temperature for the gamma '-phase (line a), into an intermediate form and the latter then being finally forged to give the end form in a second isothermal hot-forming step (curve c) just below the solution-annealing temperature for the gamma '-phase. For the first step, a degree of deformation epsilon of of at least 0.7 at a mean deformation rate epsilon of about 10x10-3s-1 is required here. The second step is carried out at deformation rates epsilon which are one to two powers of 10 lower than those of the first step.