GEARENCH SCT3672 PETOL SURGRIP Casing Tong - Manual (Page 16)

14
Weld Repairs
Scope:
This procedure is to be followed for minor repairs of crack indications in heat treated alloy
steels. A weld repair shall be considered minor when the depth of the cavity does not exceed
30% of the actual wall thickness or 1 inch, whichever is smaller, or when the extent of the
cavity does not exceed approximately 10 square inches. Major weld repairs must be
performed by Gearench or an approved repair center using appropriate procedures followed
by full heat treatment and load testing
.
Application:
This procedure applies to steel castings, forgings and, wrought with carbon content between
0.25% and 0.31%.
Weld preparation:
The crack indication is to be removed by carbon arc gouging, grinding, or machining until all
indication is removed. Magnetic particle inspection shall be used to verify that the crack
indication has been removed.
Filler material and process:
Repairs shall be made with the FCAW process with a filler material of class E71T-1 or
equivalent with CO2 shielding gas by a qualified welder.
Preheat:
Preheat the weld area to 400°F minimum.
Interpass temperature:
The interpass temperature to be 850°F maximum. All weld slag to be removed prior to
application of additional layers.
Post weld heat treatment:
Post heat immediately after welding to 400 - 800°F for 4 minutes minimum at temperature.
Wrap in insulating blanket and allow to slow cool to ambient temperature.