Hydrogen Behavior in a Plasma-Charged Dual Phase Stainless Steel

Duplex stainless steels (DSSs) are usually used in many industrial applications due to their high mechanical properties, good resistance to pitting corrosion, stress corrosion cracking (SCC) and good weldability. Also, another advantage of DSS, compared with austenitic type is low cost. However, in hydrogen containing environments, hydrogen embrittlement phenomena occur, leading to a degradation of the mechanical properties. For better understanding of the hydrogen embrittlement in duplex stainless steels, it is necessary to characterize the distribution and transport of hydrogen in or between the ferrite and austenite phases. To do this, it is effective to charge the specimens with hydrogen of amount larger than the impurity or internal hydrogen level. Two charging methods have been reported so far: electrolytic cathodic charging and plasma charging. Little has been known for the latter although it has several advantages: larger hydrogen amount and less extent of surface damage. In this paper, hydrogen has been introduced into a DSS, JIS SUS329J4L, by plasma charging method, and then its behavior has been evaluated as a function of charging condition, by means of tensile test, and thermal desorption spectroscopy.