Standardisation and design criteria relating to high temperature tensile and creep properties

In view of the rapidly increasing demands for creep resistant steels and alloys in the country a comprehensive scheme is underway for evaluation of long-time creep and elevated temperature tensile properties of indigenously produced alloys at the National Metallurgical Laboratory in close collaboration with the producers and users of high temperature steels and alloys. Elevated temperature yield or proof stress and long-time creep and stress-rupture properties are essential data on which the current national and international design codes for high temperature equipments are based. The recent developments in standardisation of testing techniques for hot-yield/proof stress, creep and stress-rupture data have been discussed. To minimise scatter in creep data and to ensure reproducibility of results, it is considered essential to make rational classification of the alloys and to control the test variables, including standardisation of test procedures and calibration of testing equipments. (Mr. R. Choubey, Scientist and Dr. T. Banerjee, Scientist-in-charge, National Metallurgical Laboratory, Jamshedpur)