STRAIN-HARDENING CHARACTERISTICS OF A COMMERCIAL GRADE ANNEALED AISI-202 ALLOY

Strain-hardening characteristics of annealed sheets of high-manganese austenitic stainless steel (AISI 202 grade) have been investigated. Fo ur empirical relations based on total and incremental stress and strai n were used to study the work-hardening behaviour in the annealed shee t of the alloy and to obtain strain-hardening coefficients n. An equat ion Delta sigma = K(Delta epsilon)(n) appears to represent the flow cu rves by a single stage of work-hardening. Two work-hardening stages ar e found for the equation sigma(t) = K(epsilon(t))(n) using total stres s and strain. Other empirical relations produce multiple stages and n values. The values of n are found to decrease as the sheet orientation changes from rolling direction to transverse direction. The n values are found to be in the range of 0.75 to 0.85 and 0.36 to 0.57, respect ively, for the equations Delta sigma = K(Delta epsilon)(n) and sigma(t ) = K(epsilon(t))(n). An attempt has also been made to estimate the n values theoretically from true strain data and expressions were derive d for various relations. The study was carried out on two sheet thickn esses and four orientations.