STUDY ON THE EVALUATION METHOD FOR SUPERPLASTICITY OF DUPLEX STAINLESS STEEL

摘要

Aiming at the problem of long duration of superplastic tensile tests for materials with a large elongation, a new method for evaluating the superplastic properties of duplex stainless steel (DSS) is proposed. In this paper, relative values of stress difference D and stress variation factor f are introduced to predict the elongation, delta. Elongation can be predicted with the relational expression between D and delta as long as the specimen is stretched only by 500 % during the superplastic uniaxial tensile test. Factors affecting elongation include the thereto-mechanical treatment and superplastic-deformation conditions. For D552205, the change trend of f and influencing factors is similar to that of elongation and influencing factors.