Relationship between FRW and AE for real-time quality evaluation of engine valve production and the creep life prediction

An experimental study was conducted not only to optimize the friction welding(FRW) conditions for the dissimilar heat resisting materials(SUH3-SUH35) of engine exhaust valves, but also to investigate the quantitative relationship between the weld quality of strength and toughness and the total number of acoustic emission(AE) counts. And also the high temperature creep life prediction of the friction welded joints of engine exhaust valve materials was investigated by the initial strain method(ISM). A quantitative correlation between the total number of AE counts and the weld quality appears to exist, and the optimum weld quality more than 100% of joint efficiency can be detected in real time during processing by the use of AE techniques. And also 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.