I will appreciate expert opinions on the following: 10" Sch 100 (19 mm) ASME 312 TP304L pipe welded to the same size ASME SA106 Gr B pipe. The welds and the surrounding SS pipe (4" from the weld) mistakenly post weld heat treated to CS pipe requirements: soaking at 630 C approx 1 hour, and heating and cooling 150 C/hr from 400 to 630 C and 630 C to 400 C respectively. total, approximately 3 hours between 400 C & 630 C. Questions: (1) are sensistization and IGC of welds and 304L base metal real concern for the above temp. and time ? (2) what's the best corrective action considering the service is water at high pressure (1600 psi) and temperature (315 C); (3) Can an IGC test such as ASTM E262 detect the IGC ? if yes, and if the test passes, is it ok to use it as-is, and (4) any proposed online reference on the subject ? Pls post your comments ASAP. Thank you.

Mr. Hendrix, thank you for your reply. 309L consumables were used in welding, and the use/service is indicated in my original request. This is a new construction with a design life of 30 years. I will appreciate any further comments. RK