Determination of CCT diagrams by thermal analysis after simulated hot deformation processes

Publisher Website
Google Scholar
Abstract
By use of the hot deformation simulator (Wumsi) the plane strain hot compression test permits the simulation of hot forming processes up to a logarithmic strain of 2.5, whereby the cooling rate of the specimen after the deformation can be varied within a wide range. By employing a recently developed method the (residual) strengthening S of austenite is determined during any anisothermal deformation sequence by evaluating the flow curves. In this way the effective S‐value, corresponding to the transformation start, can be established. In order to determine the transformation temperatures, the stored cooling curves are differentiated numerically, whereafter the transformation temperatures are marked on each cooling curve. Such marked cooling curves are plotted on a graph with zero time taken as the moment of crossing the A3 temperature. The transformation lines can be traced through the markings, so that a complete continuous cooling transformation (CCT) diagram of a steel after a simulated hot deformation schedule can be obtained directly on the screen of a graphic terminal.