Influence of aging heat treatment temperature on the mechanical properties of maraging steel 300 for application in ballistic armour

ABSTRACT

Maraging steels are special ultra-high-strength and high-tenacity steels, but despite their remarkable properties, their applications are still limited due to their high production cost. The aim of this work is to evaluate the relationship between the formation of precipitates and the content of reverted austenite, correlating with the hardness and changes in tensile mechanical properties in a class 300 maraging steel subjected to different heat treatment conditions, to serve as analysis parameter in its use in ballistic armor. Samples of maraging 300 steel were treated in 29 different aging conditions and the precipitation hardening behavior was analyzed using different techniques, such as: ferritoscopy, hardness test in as-received and aged situations, and tensile testing at temperatures of 440, 480 and 570 °C, in order to verify the influence of the austenitic phase on the mechanical properties. The influence of overaging was observed in the 570 °C sample, resulting in a decrease of approximately 31% in mechanical strength and an increase of around 40% in ductility, compared to the sample aged at 440 °C, indicating an improvement in the toughness of the material.

Keywords:
Maraging Steel 300; Ferritoscopy; Rockwell C Hardeness; Tensile Test