Many reactor pressure vessels for chemical, oil refining and coal conversion process have been successfully operated at elevated temperatures under high pressure hydrogen. At present, it is well recognized that appropriate cares shall be taken in the design, fabrication and operation for the safety of these reactors, since hydrogen-induced material degradations have been observed in existent hydro-desulfurizing reactors for oil refining.
It has been pointed out that one of the key problem is the disbonding or cracking at the transition zone of overlay and base metal interface.
This report summarizes and discusses about;
a) Fundamental study on the effect of welding parameters of strip overlay welding process on the sensitivity to hydrogen-induced disbonding.
b) Discussions for reducing disbonding susceptibility.
c) Experimental results carried out on above concepts.
The main results obtained in this investigation are as follows;
1) With respect to the susceptibility to hydrogen induced disbonding, there observed no significant effects of strip overlay welding conditions.
2) The stainless steel overlay weld metal of austenitic-martensitic duplex structure exhibited satisfactory resistance to the disbonding than that of austenite plus several percents ferrite structure.
3) The overlay metal of austenitic-martensitic duplex structure can be deposited by controlling welding current and travel speed to the extent considerably higher than convensional range.
