METHODS FOR TREATING ALLOYS Russian patent published in 2019 - IPC C22C38/58 C22C38/54 C21D8/00 C21D11/00 

FIELD: metallurgy.

SUBSTANCE: invention relates to metallurgy, in particular to a method of processing a workpiece made of an austenitic alloy, providing suppression of sigma-phase precipitation. Method includes at least one processing step selected from the group consisting of thermomechanical processing of the workpiece and cooling of the workpiece. Workpiece consists of an austenitic alloy containing, based on the total weight of the alloy, wt. %, up to 0.2 carbon, up to 20 manganese, from 0.1 to 1.0 silicon, from 14.0 to 28.0 chromium, from 15.0 to 38.0 nickel, from 2.0 to 9.0 molybdenum, from 0.1 to 3.0 copper, from 0.08 to 0.9 nitrogen, from 0.1 to 5.0 tungsten, from 0.5 to 5.0 cobalt, up to 1.0 titanium, up to 0.05 boron, up to 0.05 phosphorus, up to 0.05 sulphur, the balance is iron and impurities. During said at least one step, the austenitic alloy is at temperatures ranging from the temperature directly below the calculated dissolution temperature of the sigma phase of the austenitic alloy to the cooling temperature for a time not exceeding the critical cooling time. Calculated sigma phase dissolution temperature, cooling temperature, and critical cooling time are functions of the composition of the austenitic alloy.

EFFECT: improved mechanical properties and corrosion resistance of the alloy.

48 cl, 17 dwg, 2 tbl, 7 ex