The effect of heat treatment on mechanical properties and corrosion behavior of AISI420 martensitic stainless steel

Martensitic stainless steels are widely used for their good mechanical properties and moderate corrosion resistance. However, the need for superior properties in specific applications (e. g. steam generators, mixer blades, etc.) led to wide researches on the performance improvement of these steels. Heat treatment was recommended as one of the best ways to this regard hence the effects of astenitizing temperature and time, and tempering temperature on the microstructure, mechanical and corrosion properties of AISI420 have been studied. In the current work the experimental results showed that the austeitizing temperature significantly affects mechanical properties. The increase of tempering temperature led to precipitation of M7C3 and secondary hardening in the range of 400-500 degrees C. SEM micrographs of the fracture surfaces showed a mixed fracture mechanism (brittle and ductile) at 200 degrees C and 700 degrees C and brittle mechanism at 500 degrees C. The Polarization curves were not significantly affected by the increment of austenitizing temperature. (C) 2010 Elsevier B. V. All rights reserved.