Hot Spin Tester

Abstract

A hot spin tester has been designed in order to carry out the investigation of the strength and creep properties of high temperature alloys for the gas-turbine rotor. The stress for design of the machine has been laid upon the accurate measurements and controls of the test conditions. The maximum dimensions of the specimen put to test are 500 mm in diameter and 100 mm in thickness. The test specimen, mounted on a flexible shaft with its axis vertical in a vacuum furnace, is driven by a geared universal-motor and its speed is controlled automatically by means of an electric circuit. The maximum speed for long time test is 25000 r.p.m. The uniform specimen temperature up to 1000°C can be attained by the electric furnace. The radial displacement at 70, 140 and 210 mm radii of the disk can be measured with the accuracy of 0.01 mm by the optical apparatus designed specially for the purpose, when the disk is rotating at high speed and high temperature, so that not only plastic and creep strains but elastic ones can be obtained with a high accuracy. For bursting tests of small disks, such as small turbo-charger rotors, an air-turbine attachment has been designed and put to operation, covering the speed range up to 100000 r.p.m.