The Deformation Behavior of Types 304, 316, and 317 Austenitic Stainless Steels During Hot Torsion

Abstract

AbstractContinuous and interrupted hot torsion tests were performed in the 900–1100°C temperature range at surface strain rates of 0.1–5 s−1 on three types of 18:8 austenitic stainless steel. During continuous deformation, the strain for recrystallization fell and that for fracture rose as the temperature was raised and strain rate lowered. For each type of stainless steel, the flow stress was related to temperature exponentially, strain rate logarithmically, and was consistently higher for the highest molybdenum bearing type 317.The interrupted deformations were conducted such that the interruption times were of equal duration, these being 20 or 40s after repeated equal strains of 0.2. The static softening mechanisms operating during anyone interruption were inferred from the fractional softening between passes and by comparison of the series of pass flow curves with that produced by continuous deformation. The restoration mechanisms were static recovery, static recrystallization and grain growth. The am...