Hydrogen embrittlement of 4340 steel due to condensation during vaporized hydrogen peroxide treatment

► Exposure of low-alloy, high strength 4340 steel to water vapor with 500 or 1000 ppm hydrogen peroxide for 4.8 h does not lead to hydrogen embrittlement per ASTM 519E-06. ► Exposure of low-alloy, high strength 4340 steel to 35 wt.% H2O2 in water for 4.8 h does not lead to hydrogen embrittlement per ASTM 519E-06. ► Operation of vaporized hydrogen peroxide decontamination chambers at 1300 or 1600 ppm hydrogen peroxide concentration can lead to significant condensation with very high concentrations of H2O2 (50-75 wt.% H2O2) in the condensed liquid ► Exposure of low-alloy, high strength 4340 steel to vaporized hydrogen peroxide treatments at 1300 or 1600 ppm hydrogen peroxide concentration for 4.8 h led to extensive condensation of high H2O2 concentration (∼64 wt.% H2O2) in the process chamber and hydrogen embrittlement of the steel per ASTM 519E-06.