GEARENCH SCT614H PETOL SURGRIP™ Casing Tong - Manual (Page 17)

15
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
0.15% 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 made with the FCAW process shall use a filler material of class E120T5-K4 or
equivalent with CO2 shielding gas. Repairs made with the SMAW process shall use a filler
material of type E-12018-M. All welding is to be performed by a qualified welder.
Preheat:
Preheat the weld area to 300°F minimum.
Interpass temperature:
The interpass temperature is to be 600°F maximum. All weld slag to be removed prior to
application of additional layers by chipping, grinding or wire brushing. Do not peen the
weld repair.
Post weld heat treatment:
Do not allow weld to cool below 300°F before stress relief. Post heat immediately after
welding to 1010 - 1040°F for 1 hour per inch of thickness, 2 hours minimum at temperature.
Water quench after stress relief.