Hydrogen Embrittlement Enhanced by Plastic Deformation of Super Duplex Stainless Steel

摘要

The effect of variations in plastic deformation percentage on hydrogen embrittlement of super duplex stainless steel alloy was investigated. Samples were strained to 4%, 8%, 12%, and 16% of plastic strain prior to hydrogen charging. Sufficient hydrogen for embrittlement was achieved by cathodic charging in 0.1 M H_2SO_4 for 48 h at a current density of 30 mA/cm~2. Hydrogen embrittlement susceptibility was highly dependent on the amount of plastic deformation. Experimental results showed that prestraining of super duplex stainless steel and hydrogen charging affected the elongation and the values of the strain required to failure. The total elongation for the samples with no prestraining deformation and tested in air was 29%. This elongation reduced to 25% when the same sample condition (no prestraining) charged with hydrogen. Further reduction in elongation and strain to failure was observed when the prestraining samples were charged with hydrogen prior to tensile testing. Load-displacement results showed that as the percentage of the plastic deformation increased, the elongation and strain to failure decreased. Comparison between the prestrained samples, charged and uncharged with hydrogen, showed a noticeable difference in strain at failure in the hydrogen charged specimens.