Welding Procedure Specification (continued) welded” condition, the PQR must be tested in the as-welded condition. Technique There are several welding variables that are listed under the heading “technique.” Whether weave beads or stringer beads are used can be presented here. Any limitations on the width of the weave bead can be listed under this heading. This is a good time to note that welding standards published by ASME1, AWS, and even the military do not place limits on the width of a weld bead deposited with the SMAW process. Any such restriction on the width of a weave bead is imposed by the manufacturer and not the code. When notch toughness is required, the width of the bead is 36 Inspection Trends / January 2011 controlled to limit the heat input by controlling the travel speed. Other information listed under the heading of “technique” include travel speed, whether single-pass or multipass welds are used, the need for and method of backgouging, cleaning, and welding positions. Technique is a catch-all category for any information not listed elsewhere in the WPS. Joint Details A WPS can address the requirements applicable to a single joint detail or many joint details. A WPS can easily accommodate the details for one or two joints, but a general WPS that covers many different joints can easily grow in size to the point where it weighs more than the components being welded. Once again, the annex comes to the rescue. A separate annex can list all the appropriate joint details, fit-up requirements, and tolerances applicable to the work — Fig. 3. The WPS can refer the reader to the appropriate annex used to show the details of each joint. When an annex is used, each joint detail should be assigned a unique identifier. There are a couple of systems in place already. Two that come to mind are the joint designations found in AWS D1.X and MIL-STD- 22D. There is no need to reinvent a system when it is easier to adopt something that already exists. Acceptance Criteria Welding standards typically do not include a requirement for the WPS to list the applicable visual acceptance criteria for the weld. However, the WPS and the drawings are the two primary documents the welder works with. What better vehicle is available to define what visual acceptance criteria is appropriate for a particular job? Technique WPS: GTA/FCA-P1F6 Process: GTAW FCAW Layer: Root and second layer when CJP Intermediate and cover layers for from one side without backing is specified. all fillet welds, PJP, and CJP welds made with backing. Position: All All Progression: Vertical Uphill Vertical Uphill Travel Speed: 2–5 in./min 4–12 in./min Stringer/Weave: Either, split layer required when Either, split layer required when previous layer exceeds 3⁄8 in. in width. previous layer exceeds 5⁄8 in. in width. Single/Multiple Electrode: Single Single Electrode Spacing: NA NA Single/Multiple Pass per Side Either Either Peening: None None Chamber: None None Method of Cleaning: Refer to Annex B Refer to Annex B Method of Back Gouge: Refer to Annex B Refer to Annex B Heat Input Limitations: 60 kJ/in. 60 kJ/in. Other: FCAW electrodes shall be stored in the manufacturer’s sealed container until needed. Once opened, the spool of electrode shall be used within an 8-hour period, electrode not used shall be discarded or any electrode not exposed for the full 8-hours may be returned to a vented electrode holding oven set to 250° F minimum. This example of a WPS is for illustrative purposes only. It is not intended to meet the specific requirements of any welding standard and is not intended for production welding. ASME SA285 A, B, C Plate ASME SA333 1, 6, 10 Pipe, seamless and welded ASME SA334 1, 6 Tube, welded ASME SA352 LCA and LCB Castings ASME SA372 A Forgings 1. ASME does have a restriction on the bead width when a repair is made and PWHT is not used.
Inspection Trends - January 2011 - Winter
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