This article is about Weld Repair Procedure for Piping for mechanical, piping and welding engineers when they want to work in Adsorbent Tower Internal in Plants and refineries.
Weld Repair Procedure for Piping / Beam
1. Scope
This specification covers the repair procedure for the following item on the shop fabrication at Hitachi Zosen Corporation (Hitz).
Item: J12-C-0201A/B ADSORBENT TOWER INTERNAL
2. Reference Codes and Applicable Specifications
2.1 Reference Codes
ASME Sec.VIII Div.1 2010 Edition including up to 2011A Addenda
ASME Sec. IX 2010 Edition including up to 2011A Addenda
2.2 Vendor Specifications
INSPECTION PROCEDURE FOR BEAM
INSPECTION PROCEDURE FOR PIPING
WELDING PROCEDURE SPECIFICATION FOR PIPING/BEAM
2.3 Customer’s Specifications
SAES-W-010 WELDING REQUIREMENTS FOR PRESSURE VESSELS
32-SAMSS-020 MANUFACTURE OF TRAYS AND PACKING
32-SAMSS-004 MANUFACTURE OF PRESSURE VESSELS
3. Weld Repair Procedure for Piping / Beam for Tower Internal
3.1. Repair without welding
For minor defect such as undercutting, overlapping or surface imperfections (chip mark, blemishes,
scratch or other irregularities on weld or base metals) shall be repaired smoothly by grinding or
machining provided the base metal thickness is not less than specified one.
3.2. Repair by Welding
When defect occurs on weld metal or base metal and required base metal thickness by design is
reduced, the defect shall be repaired by welding in accordance with this repair procedure.
3.3. Repair procedure
1. Confirmation of the area to be repaired
When the defect was detected by non-destructive examination or other methods the area of
defect shall be confirmed by suitable non-destructive examination such as ultrasonic testing.
2. Removal of defect
(1) Defect shall be removed to sound metal by grinding, chipping machining and/or arc gouging.
When arc air gouging is used, grinding or chipping shall be applied to remove adhered
carbon and scale.
(2) The excavated groove shall be widened by grinding to facilitate the welding.
3. Confirmation after removal of defect
The area on which defects have been removed shall be examined by either magnetic particle
examination or by liquid penetrant examination to ensure complete removal of defects.
4. Repair by welding
- For repair of defects in weld metal, the welding procedure shall be applied to the same process as the one used for the joint in principle. For repair of defect in FCAW joint, GTAW process may be used with the filler metal of equivalent chemical composition and mechanical properties.
- For the defect in the base material, the repair shall be done by GTAW with filler metal of equivalent chemical composition to the base material.
- The repair welding shall be carried out in accordance with approved WPS and qualified welders I welding operators.
- Repair area of base material shall be smoothly finished by grinding.
- Welds may be repaired twice at any defect location.
- Cracks that are related to the base metal or welding consumables shall be evaluated by Consulting Services Department(CSD) before any repair attempts.
- Damage or deformation to the base metal or welds, including dimensional changes, caused by external forces (intentional or accidental) requires special repair and inspection procedure be submitted to Saudi Aramco Inspection and if necessary forwarded to CSD for review and approval prior to undertaking the repairs.
5. Examination for repair
The repaired area shall be re-examined by the method of the examination by which the defect as detected originally.