Comparison of High-Temperature Alloys Tested as Blades in a Type B Turbosupercharger

Abstract

Abstract The authors describe briefly a series of jet tests, utilizing gas produced from the combustion of Diesel fuel oil, as a means for comparing the resistance of a number of high-temperature alloys to hot-gas impingement. The deficiencies of this method for simulating conditions in a gas turbine are discussed. The paper is concerned principally with comparative tests of a number of high-temperature alloys when tested in the form of blades in a Type B turbosupercharger. The test rotor contains 142 blades, representing 12 different alloys. Both wrought and precision-cast blades are included. Tests were made at eight temperatures, ranging from approximately 1200 to 1500 F, test runs at each temperature being of 50 to 150 hr duration, except in the case of the 1500 F test run, which was continued for 1000 hr. After several of the test runs, measurements were made to determine the amount of permanent extension in the blades and disk. The extension of the blades and disk accompanying progressively higher testing temperatures is shown graphically. A procedure for correlating the metal temperature of the blades with that of the combustion gas in the nozzle chamber of the supercharger is described.