Engineering Data BI011160
These cracks can propagate in service and lead to ultimate failure of the part. It is necessary to adhere strictly to recognized good welding practice regarding the handling, storage and use of low hydrogen electrodes. To avoid underbead cracks, remove all oil or grease or other contaminates from the surface and be sure the steel is dry. Preheat to the required temperature. Use only dry electrodes taken from the electrode oven. After exposure to the air, the electrodes must be returned to the oven. Time limit outside the oven is four hours for E7018 and two hours for E8018-C1 electrodes.
Repair Welding Of Cracks
Joint Preparation for Repair of Cracks
Remove the entire crack by arc air-gouging or grinding. Prepare a V-groove of approximately 4560o included angle for rewelding. If cracked through the full thickness and if it is possible to make the repair from both sides, a double V preparation is preferred. When welding from both sides, back-gouging for complete penetration is always recommended. When it is not physically possible to back-gouge and weld the second side, an alternate approach must be taken. Sometimes it is possible to gouge through to completely remove the crack, then fit a backup bar on the underside to facilitate making a complete penetration weld. NOTE: The backup bar must fit tightly to the underside otherwise poor welding conditions conducive to cracking may occur.
8 - 26 November 2012
7295 Electric Rope Shovel
SM141490-EN
