The high temperature creep life prediction of the friction welded joints (IN713C-SCM440) of turbine impeller materials was investigated by the initial strain method(ISM). So, an experimental equation was drawn for the creep life prediction at the initial time of creep by the ISM techniques. It seems likely that extension of this study could lead to the development of an in-process quality monitoring system and a real-time creep life prediction system based on the acoustic emission events and the initial strains of creep, respectively.
One of the important concern is a reliable method of evaluating static creep properties by the ISM(initial strain method) and AE(acoustic emission) techniques. No reliable method seems available at present to evaluate or predict such static creep properties the friction welded joints of turbine impeller components by the ISM and AE techniques 12–15). Therefore, in this paper, a study on development for initial-real-time -prediction of high temperature creep strength and creep life during long time for the friction welded joints of IN713C to SCM440 steels was performed on round-bar type specimens under static load at the temperature range of 500 to 700ºC. Especially, the research results are an important contribution to the fundamental reference data for designing, manufacturing or maintaining the various turbochargers such as turbine impeller.
Oh 5) discovered that the creep initial strain (ε0) can be quantatively related to prediction of static creep properties(fracture time tr, creep rupture stress σ, etc.) in short term creep test of various heat resisting steels(SUS303, SUH3) and the friction weld under static load at 700º C and suggested the following model: