Project Title

Development and application of small scale bending tests for residual property assessment of high temperature materials in turbines

Project Images

Image Caption: Stress distribution, as predicted by finite element analysis, in a properly designed cantilever sample. The symmetry in the stress field across

Image Caption: Load jump tests (left) showing steady state deflection rate following brief primary stage. Suitable plotting of deflection rate against normal

Web Abstract

The proposal aims to develop a bending creep based technology and the required science for assessment of residual life of materials in power generation, enabling a designer to make intelligent life predictions. The methodology is based on testing miniaturized samples, which will, thereby proffer extracting very small volume of material from in-service components without impairing their integrity or interrupting regular operation. Miniaturized cantilever samples will be micro-machined from virgin and in-service components supplied by BHEL. Bending creep tests on these samples will be performed at high temperatures and various stresses in industrially relevant range for obtaining critical creep parameters, such as stress exponent and activation energy, and establishing microstructure-property relationship. The obtained results from bending creep will be validated against the uniaxial tests using ASTM standard samples. Development of such a small-scale test methodology will be of practical utility in many other branches of materials engineering, including welded joints, cladding and tubes in nuclear reactors which experience varied radiation dosage across their section thickness.