Resumen de Dilatometric analy sis during tempering of martensite and nanostructured bainite

Víctor Ruiz Jiménez, Francisca García Caballero, Carlos García Mateo

• Tempering heat treatments are commonly used in steels with elevated hardness and fragility with the aim of varying their mechanical properties by decreasing the residual stress and also reducing the matrix carbon supersaturation by means of controlled precipitation, secondary hardening. The final outcome usually is an increase in ductility and toughness scarifying only small levels of strength as compared to the as quench microstructure. To obtain the desired secondary hardening effect, it is necessary to control the tempering conditions and to include, in the chemical composition of the steels, judicious quantities of strong carbonitride and intermetallic forming elements as Mo, V and Cr.