CREEP PROPERTIES EVALUATION AT 600°C OF MARAGING 300 STEEL SOLUTION TREATED

Abstract

Maraging steels are alloys with Ni-Co-Mo-Ti with ultra-high resistance and broad application, with fundamental interest in the aerospace sector due to high mechanical resistance combined with a good fracture toughness. This steel has been proposed to replace the steels 300M and 4340 in the Brazilian rocket engine case for Satellite Launcher Vehicles. Maraging steels have a metastable martensitic structure that can revert to austenite when heated in temperatures close to the aging temperature, and this effect can be enhanced with the temperature increasing and time of treatment. Therefore, the study of creep behavior in elevated temperatures has technological importance to the development of this material. In this work the creep behavior of a 300 grade commercial maraging steel solution treated is evaluated by carrying out creep tests at 600ºC and in a stress range of 200MPa to 500 MPa. Creep parameters, such as steady state creep rate (ε·s), final creep time (tf), and stress exponent from secondary creep (n) are determined, considering that they are important to evaluate the creep resistance of the material.

Keywords

• Maraging steel; Creep; Mechanical behavior at high temperature.