GENERAL NOTES:
(a) When it is impractical to postweld heat treat at the temperature specified in this Table, it is permissible to carry out the postweld
heat treatment at lower temperatures for longer periods of time in accordance with Table UCS-56.1.
(b) Postweld heat treatment is mandatory under the following conditions:
(1) for welded joints over 11/2 in. (38 mm) nominal thickness;
(2) for welded joints over 11/4 in. (32 mm) nominal thickness through 11/2 in. (38 mm) nominal thickness unless preheat is
applied at a minimum temperature of 200°F (95°C) during welding. This preheat need not be applied to SA-841 Grades A and
B, provided that the carbon content and carbon equivalent (CE) for the plate material, by heat analysis, do not exceed 0.14%
and 0.40%, respectively, where