Modeling of Grain Size Change and Phase Transformation of Stainless Wire during Drawing with Cryogenic Cooling

In this article, the results of modeling a new technology for processing stainless steel wire in the Deform software package are compared with the results of a laboratory experiment. The new technology consists in preheat treatment to obtain an austenitic microstructure and traditional drawing, followed by cryogenic cooling in nitrogen. The analysis of the microstructure evolution during modeling showed that as a result of such processing, an ultrafine-grained microstructure in a wire can be obtained. Moreover, the level of martensite formation is directly dependent on the presence of metal cryogenic cooling. Thus, when processing a thin billet from 6 to 5 mm, the most effective conditions under which martensite is formed in almost the entire section are a reduced drawing speed and the absence of intermediate heating. In this case, the level of martensite in the cross section is 88%. The results of the laboratory experiment confirm the simulation results. As a result of deformation of stainless steel wire using a new technology, an ultrafine-grained microstructure consisting of a mixture of austenite and alpha-martensite was obtained.