METHOD FOR PROCESSING METAL AND ALLOY BILLETS

摘要

The invention relates to metallurgy, more precisely to the thermomechanical treatment of billets having a large-grained laminar structure, in particular to titanium and alloys thereof, in order to obtain a defined microstructure for said billets. The aim of the invention is to increase grain reduction, i.e. to obtain a grain size of 5.0 to 10.0 mkm and less for large-sized billets, including billets of 200 kg and more; to provide the billets with a homogeneous or a specified heterogeneous cross section structure; to reduce a specific energy intensity and to increase the size of the processed billet. The invention is also directed at a reduction of the labor coefficient of the process as a whole. The inventive method consists in processing metal and alloy billets by means of inelastic deformation to a degree and at temperature-speed conditions making it possible to reduce the grain size by processing the entire billet or a specified part thereof in one or several stages. In the case of one-stage processing, a torque load is a preferential or exclusive loading component. In the case of several stages, a torque load is a preferential or exclusive loading component used mainly for the first step and tensile and compressive loads are used as preferential or exclusive loading component for the subsequent stages. At least the stage with the torque load is carried out in several processing steps and the loading conditions are selected in such a way that it is possible to transform the microstructure during the deformation and/or during the heat treatment carried out between the stages or steps.