Development and Application of Laser Peening in Japan

Recent advances in laser technology have yielded amultitude of innovative processes and applications invarious industries. Laser peening without protectivecoating (LPPC) is a typical example and blazes a trail inthe field of preventive maintenance of operating nuclearfacilities, taking full advantage of inertia-less processover mechanical treatment1]. LPPC introduces a compres-sive residual stress on metal surface by simply irradiat-ing laser pulses under water environment2] . A remotepro…

Development and Application of Laser Peening in Japan

This paper reviews the current status of research and development on laser peening without protective coating (LPPC) in Japan. LPPC is an innovative process since it does not require any surface coating that is formed prior to laser irradiation in conventional laser peening for preventing the surface from melting. Surface residual stress of various metal materials was converted from tensile to compressive by LPPC.High cycle fatigue property was remarkably improved for steels, aluminum alloys and titanium alloys. Accelerating stress corrosion cracking (SCC) tests showed that LPPC completely prevents SCC of sensitized austenitic stainless steels, nickel-based alloys and their weld metals. LPPC has been utilized to combat against SCC in Japanese nuclear power reactors since 1999.