A Study on Hydrogen Discharge by Electrochemical Technique

摘要

Hydrogen embrittlement (HE) mitigation on the low alloy steel was studied using electrochemical technique. This method can be applied to reduce HE susceptibility. Hydrogen induced cracking (HIC) characteristics of the low alloy steel was investigated in aerated and deaerated borate buffer solution (0.3M H_3BO_3 + 0.074M N_2B_4O_7, pH 8.4). The electrochemical properties of the low alloy steel showed passive behavior in this environment. By performing galvanostatic and potentiostatic test, hydrogen was charged and discharged to specimens respectively. By applying the potential of +630 mV_(SCE), the accumulated hydrogen was eliminated electrochemically. A specimen discharged for 24h indicated the efficiency of the hydrogen discharge up to 99.9 percent. Slow strain rate tests (SSRT) results showed that a specimen with higher hydrogen concentration revealed inferior mechanical properties such as shorter time to fracture, lower elongation, ultimate tensile strength and yield strength values. Furthermore, SEM fractographs revealed that the higher the hydrogen concentration is, the more probable the features of brittle fracture are.