AWS D10.22/D10.22M PDF
This standard describes a method of applying controlled heat to weld joints and a limited volume of base metal adjacent to the joints, as opposed to heating the complete weldment in a furnace or oven. This standard is written to apply to the heating of creep strength-enhanced ferritic steels (P-No. 15X) by the use of electric resistance heating pads.
The basis of this document is the proper application of heat in sufficient surface area to ensure that the temperature on the inside diameter (ID) of the component at the root of the weld achieves the necessary minimum temperature.