Evaluation of Weld Preheat and Postheat Requirements for Pressure Vessel Materials
- Babcock and Wilcox Co., Mt. Vernon, IN (United States). Power Generation Group
Hydrogen induced cracking can be a serious problem if proper precautions are not taken. Current procedures used by B&W included the use of preheating, low hydrogen welding procedures, and low carbon content weld metals. Several years ago B&W initiated a program to determine if it is necessary to maintain the preheat temperature until the part is given a high temperature postweld heat treatment. This report will document the results of this test work. In addition, the B&W Company how has many years of successful experience in dropping preheat on commercial pressure vessels prior to stress relief treatment. Laboratory tests, which included weldments up to 6-3/8-inches thick, showed that the preheat temperature during welding is an important factor in preventing hydrogen induced cracking. The maintenance of the preheat temperature after welding is not required to prevent cracking. This was shown to be true for highly restrained welds even when consumable with high moisture levels were used. The Appendix provides tabulated data on 97 commercial nuclear reactor vessel welds which were made where the preheat was dropped prior to the postweld stress relief heat treatment. Careful nondestructive examination showed that hydrogen induced cracking did not occur in any of these weldments. 15 figs., 6 tabs.
- Research Organization:
- Babcock and Wilcox Co., Mt. Vernon, IN (United States). Power Generation Group
- Sponsoring Organization:
- US Atomic Energy Commission (AEC)
- DOE Contract Number:
- AC15-76CL50003
- OSTI ID:
- 714756
- Report Number(s):
- DOE/CL/50003--T38; 610-0255; ON: TI91020355
- Country of Publication:
- United States
- Language:
- English
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