Correction of the coarse-grained structure in heat treatment of steel (once again the b point of Chernov)

Previously abstracted from original as item 9206-56-0821. A method for correcting the coarse-grained structure of steels, proposed > 120 years ago by Chernov, consists of heating a steel above a certain critical temperature, referred to by Chernov as the "b" point. Here, the physical meaning of the "b" point is examined in relation to that of the A sub 3 point. Conditions under which a distinct difference between the two critical points exists are defined. Treatments are proposed which make it possible to obtain an ultrafine-grained structure with a grain size of 1-2 mu m. Steel 38KhN3MF was treated and oil quenched.