Effect of Tempering Temperature on Hardness and Impact Resistance of the 410- 1Mo Martensitic Stainless Steels for Steam Turbine Blades

Abstract

Tempering is an important process to produce the martensitic stainless steels having the desired properties. This paper reports the influence of tempering temperature on hardness and impact resistance the modified 410-1Mo steels. The steels samples were prepared by a process sequence of induction melting, hot forging, annealing, hardening and tempering. The tempered steels were subjected to hardness and impact testing. The experimental results showed that the hardness and the impact resistance of the steels depended strongly on tempering temperature and they changed considerably at temperature 600 o C. The secondary hardening appeared at tempering temperature around 400-550 o C. The correlation of impact energy with hardness was found to fit the linear line with negative gradient with increasing of hardness value. The fractured surfaces of the impact test specimens were analyzed using SEM images.