S9074-AR-GIB-010/278 Table VI-Post Heat Requirements for Welded ferrous alloys
Applicable supplementary provisions and exceptions
Pressure vessels, turbines classes A-F, A-LT, A-1, A-2, A-3, A- 4, T-1, and T-2 For class A valves installed in P piping sytems (see 3.3.2), stress relief may be performed according to class P requirements of this table. Thermal stress relief is required for all carbon steel pressure vessel classes except it is not mandatory for classes A-3 and A-4 of weld thickness 3/4 inch and less provided (a) that carbon is less than 0.35 percent, (b) there are no nozzles with finished inside diameter greater than 2 inches or connections forming ligaments that require increase shell or head thickness, (c) that if cellulose coated electrodes are used the joints shall be preheated to 200*F minimum and this preheat maintained during welding.
Holding Tempera ture *F 2/, 3/
Material Group Number
Material Identifica tion 1/
Machinery class M 1/
Piping Class P
6/, 4/ S-1 Carbon Steel
1100- 1250
Thermal stress relief shall be performed where required for dimensional stability.
Thermal stress relief required when one or more of the following conditions are apply:
(a) Carbon content is over 0.35 percent.
(b) Weld thickness is in excess of 3/4 inch. (c) Joints 2-2/4 inches nominal pipe size (nps) and larger are welded with cellulose coated electrodes and the preheat or interpass temperature was below 200*F.
Original 62
Made with FlippingBook - Share PDF online