Effect of Cold Work on Hydrogen Embrittlement of Monel-400

The effect of cold working on hydrogen embrittlement of Monel-400 alloy has been investigated in this report. Monel-400 alloy having 50 and 60% cold working has been selected for this study. A part of these cold-worked materials is annealed. A series of slow strain rate tensile tests of the cold-worked as well as annealed materials are carried out in two different environmental conditions—air and with hydrogen charging in 3.5% NaCl solution. Alloy with 60% cold working exhibits the highest reduction in ductility with hydrogen charging. The reduction in ductility is lower for the annealed materials compared to that of cold-worked materials when tested with hydrogen charging. The results lead to infer that (i) the alloy becomes more detrimental to hydrogen embrittlement with the increase in percentage cold working, which reduces ductility significantly with increasing strength under hydrogen charging, (ii) annealing of cold-worked materials decreases their susceptibility to hydrogen embrittlement, and (iii) hydrogen damage promotes brittle fracture for the cold-worked materials.