Industrial Application of Small Punch Testing for In-Service Component Condition Assessment: An Overview

Abstract

The Sampling and Small Punch testing (SPT) is a powerful technique based on tests using miniaturized specimens machined out small sampled material of components in service. At present, it is the only existing method capable of providing experimental characterization of service exposed materials of components and materials of new built plants. Small sampling is non-invasive and SPT provides direct measured material properties. It provides a significant technology capability that facilitates assessing power plant operating equipment for structural integrity and operational condition. The new method provides utility members an attractive option to interrogate equipment for making run/inspect/repair/replace decisions. The SPT technique supported by assessment software, NDE and Metallography, used to define guidelines for components life assessment cross the power generation and petro-chemical sectors, serving both utilities, and constructors. It addresses the industrial need for personalized material and welds data required for a) lifing of plant; consumed life and residual life of components, b) convenience of repairing, replacing, life of the new welds on old components, c) cost of component deterioration, cost of normal service, d) characterizations and qualifications of blade repairs, of coating materials-methods. The first international SPT workshop was organized in June 27–28, 2011 in Nottingham, UK in order to discuss the state-of-the art SPT Creep and Fracture, and the draft CEN Cope of Practice (COP). The International SPT Experts Group serves as international forum for discussion and collaboration of industrial application of SPT methodology for in-service component life assessment. It is noted the draft CEN COP needs to be revised. Presently, European, Japanese and Indian national SPT project groups are running SPT tests and working on analysis programs. The present paper reports on a) the use of SPT in materials and component characterization, and b) drafted technical program by the international experts group to harmonize international efforts on SPT testing and analysis for efficiency and cost effectiveness. The draft program to bring the SPT methodology to standardization and develop an engineering component condition assessment tool for industrial application.