Hi, Is there any possibility that stabilized grade stainless steel 347 suffured sensitization?, If, yes why ?, Thanks

347 Stainless steel can also sensitize in service at elevated temperatures, just as non-stabilized grades. We have experienced several failures of 347 superheater tubes (1050 F steam temperature, metal temperature somewhat higher) in a few coal-fired, supercritical boilers. Sensitization was confirmed via 10% Oxalic Acid electrolytic etch (which produced a 'ditched' microstructure) and a second metallographic sample etched specifically for sigma phase (none indicated) to rule out the possibility that the oxalic acid indications was sigma phase related rather than sensitization related. A literature search on this issue indicates that unless the 347 is given a stabilization anneal, it's resistance ot sensitization is only slightly greater than that of 304. The validity of the stabilization anneal is in question for the elevated temperatures we've experienced in the superheater, and there is data 'out there' that indicates a dramatic reduction in creep properties following such a heat treatment, which would be undesireable.