INFLUENCE OF HEATING RATE AND CARBON CONCENTRATION ON THE MECHANICAL-PROPERTIES OF CARBON-STEELS

In this work, the influence of temperature and heating rate on mechani cal properties of three carbon steels (containing respectively 0.1%, 0 .38% and 1% of carbon) has been investigated. Using a specifically des igned apparatus equipped with a heating device, tensile and relaxation tests have been performed in air under three conditions of temperatur e (600 degrees C, 800 degrees C and 1100 degrees C) and for two extrem e values of heating rate (10 degrees C/s and 270 degrees C/s respectiv ely). A significant dependence of mechanical properties (such as the y ield stress and tile maximal stress) upon the rate of heating has been pointed out. For instance, at 600 degrees C, for each material, an es sential decrease of the yield stress as well as the flow stress was ob served for the heating rate of 270 degrees C/s. Moreover, for a given temperature value, our results show that this parameter also affects t he strain hardening factor as well as the strain rate sensitivity expo nent.