Method of an ultra-short femtosecond pulse and KW class high average-power laser for preventing cold-worked stress corrosion cracking in iron steels and alloyed steel including stainless steels

A method of preventing cold-worked stress corrosion cracking on a surface of the iron steels and alloyed steels including stainless steels using the ultra-short femtosecond pulse and kW class high average-power laser, wherein under the following three conditions mandatory for the development of cold-worked stress corrosion cracking in almost all iron steels and almost all alloyed steels including stainless steels, 1) corrosive environments, 2) crack advancing, residual tensile stress, and 3) a cold-worked hardened surface layer that is extremely sensitive to stress corrosion cracking in the presence of many minute cracks, dislocations, steps, pits and other defects that are originated from all types of cold working, the ultra-short femtosecond pulse and kW class high average-power laser such as a femtosecond, high average power, superconducting linear accelerator based free-electron laser is used to produce an impact of laser irradiation such that a surface layer having residual tensile stress 2) is removed by non-thermal, non-equilibrium evaporation and the hardened surface layer 3) extremely susceptible to stress corrosion cracking is completely removed by non-thermal, non-equilibrium evaporation processing quicker than heat conduction without generating any additional hardened surface layer being susceptible to stress corrosion cracking.