CAST WORK BLADE WITH MONOCRYSTAL STRUCTURE, HEAT RESISTANT STEEL BASED ON NICKEL TO MANUFACTURE LOCK PART OF WORK BLADE AND METHOD OF HEAT TREATMENT OF CAST BLADE

摘要

FIELD: metallurgy.;SUBSTANCE: invention relates to metallurgy. Cast work blade with monocrystal structure contains body, lock flange and lock part, and comprises two fragments connected by fusion zone. Fusion zone of two fragments with height 5-30 mm is located between lock flange and blade lock part. One fragment - lock part - is made out of alloy with increased short-term strength, another fragment - blade body and lock flange - are made out of alloy with increased heat resistance. Difference of temperatures of complete dissolution of strengthening γ'- phase of two heat resistant alloys T_SOLγ' is maximum 20°C, and difference of alloy densities is ~8%. The heat resistant alloy on nickel base to manufacture lock part of the work blade under invention contains wt %: carbon 0.001-0.12; chrome 6.5-9.8; cobalt 4.0-7.2; molybdenum 1.6-3.7; tungsten 2.0-4.2; titanium 3.0-4.5; aluminium 4.8-6.2; niobium 0.08-0.22; manganese 0.002 - 0.12; silicon 0.005 - 0.2; nickel - the rest. Method of heat treatment of cast blade includes homogenizing annealing at 1250±10°C for 2-3 hours with further cooling with rate 25-40°C/min to 690-710°C, further heating to ageing temperature, holding for 16-24 hours, and cooling with rate 20-40°C/min to 500°C, holding for 5-30 minutes, and air cooling.;EFFECT: increased strength of blade, and operation reliability of turbine.;5 cl, 1 dwg, 2 tbl