High Temperature Deformation Behavior of Carbon Steel in the Austenite and δ-Ferrite Regions

摘要

Stress-strain relations of carbon steels in the γ phase regions have been analyzed through the high temperature tensile tests at various temperatures from 1100 to 1450 deg C and strain rates from 10~(-4) to 10~(-2)/s using Gleeble system. During hot tensile test, a ceramic fiber tube was used to reduce the radial temperature gradient in the heated specimen. The flow stresses of carbon steels varied not only with the test temperatures and strain rates, but also with the process condition of cooling rate. The measured flow stress ofδ phase was lower than that of γ phase. The degree of strain hardening of δ phase was negligible compared with that of γ phase. A simple constitutive equation, which takes into account temperature, strain and strain rate, could successfully describe the measured flow stress of carbon steel by hot tensile test. The calculated flow stress was in good agreement with experimentally measured data.