Softening Mechanisms of the AISI 410 Martensitic Stainless Steel Under Hot Torsion Simulation

Abstract

This study investigated the softening mechanisms of the AISI 410 martensitic stainless steel during torsion simulation under isothermal continuous in the temperature range of 900 to 1150 °C and strain rates of 0.1 to 5.0s -1 . In the first part of the curves, before the peak, the results show that the critical (ε c ) and peak (ε p ) strains are elevated for higher strain rate and lower temperatures contributing for higher strain hardening rate (h). Moreover, this indicated that dynamic recrystallization (DRX) and dynamic recovery (DRV) are not effective in this region. After the peak, the reductions in stresses are associated to the different DRX/DRV competitions. For lower temperatures and higher strain rates there is a delay in the DRX while the DRV is acting predominantly (with low Avrami exponent (n) and high t 0.5 ). The steady state was reached after large strains showing DRX grains, formation of retained austenite and the presence of chromium carbide (Cr 23 C 6 ) and ferrite δ at the martensitic grain boundaries. These contribute for impairing the toughness and ductility on the material. The constitutive equations at the peak strain indicated changes in the deformation mechanism, with variable strain rate sensitivity (m), which affected the final microstructure.

Improving the Non-Destructive Test by initiating the Quality Management Techniques on an Example of the Turbine Nozzle Outlet

“…They are characterized by excellent mechanical properties and good corrosion resistance. Selected properties of 410 steel are shown in the subject of the literature [25,27,28].…”