METHOD FOR PROCESSING BILLETS FROM MULTIPHASE ALLOYS AND THE ARTICLE

摘要

The invention relates to plastic working of metals and alloys, predominantly low-plastic and hard-to-work ones, e.g., nickel-, titanium-, and iron-base high-temperature alloys, and producing billets for parts made by plastic working of said billets. The method comprises thermomechanical processing which is performed beginning with the temperature at which a total content of precipitates or an allotropic modification of the matrix exceeds 7%, followed by a stage-by-stage decrease of the working temperature down to the temperature at which a stable fine-grained microstructure of the material is obtained, with ratio between the grain size of various phases differing by not more than 10 times, the billet under processing undergoes deformation with a 1.2 to 3.9 times change in the billet cross-sectional area. When preparing billets from nickel-base alloys a stage-by-stage decrease of the working temperature is carried out so as to provide a maximum 14% gain in the gamma-phase at each stage. At the end of each process stage a successive annealing of the billet is performed.