Hmmm, now I'm more confused...
Table 4.12 (Page 150) reads that a welder qualified with backing can only weld with backing on that qualification. Section 4.23 (Page 129) reads that welders that qaulified with backing are also qualified to backgouge. There seems to be some contradiction here.
Am I missing the significance of the "If used in the WPQR test" statement in Table 4.12? Is the welder qualification generated while running a PQR w/ backing more restrictive than running a simple welder qualification? That seems odd to me.
I believe there may be a misunderstanding of the term "backing" in this instance. The misunderstanding is that for production purposes (not welder qualification) backing can be a separate material, such as a backing bar or ring, it can be permanent or removable such as is the case with a copper backing bar or ceramic backing, or it can be the base metal itself as in the case of a partial joint penetration groove weld or a double sided groove weld be it complete joint penetration or partial joint penetration.
The act of back gouging a double sided groove weld removes base metal to the depth required to obtain sound metal, usually the root of the weld deposited from the first side. The metal excavated is considered to be "backing" for the weld deposited from the first side.
So, the discussion by the instructor at FabTech is not at all out of line with what has been discussed in my response. I hope I understood your consternation and that I provided some additional useful information.
Welder qualification is not the same as qualifying the welding procedure and yes, the ranges for which the welder is qualified are different than the ranges for which the WPS is qualified when the welder is qualified by the act of welding the test plate used to qualify the WPS.
As I understand it, it boils down to the following:
- Welder is qualified with a backing bar - he is qualified for fillets, PJP, and CJP grooves made with backing or back gouged and welded from the second side
- Welder is qualified with back gouging - he is qualified for fillet welds, PJP, and CJP grooves that include back gouging and welding from the second side. He is not qualified for CJP groove that require the use of a backing bar or CJP grooves without back gouging (as in pipe joints).
- Welder is qualified without backing, i.e., the test consist of a CJP groove welded from one side without back gouging (as in a pipe weld) - the welder is qualified to deposit fillet welds, PJP grooves, CJP grooves with backing, CJP grooves that are back gouged and welded from the second side, and CJP grooves deposited from one side without backing or back gouged.
- Welder is qualified with a fillet weld - he is only qualified for fillet welds.
- Job specific joint details, i.e., non-standard welder performance tests, devised by the contractor are joint and condition specific. For instance, a manufacturer that is making outside corner joints that must be ground and finished to meet specific customer driven requirements can have the welder weld up a "sample" corner joint as a workmanship sample. The welder may be required to weld a sample and grind and finish the outside corner to demonstrate the ability to meet specific customer driven acceptance requirements. That test, or workmanship sample, is for that specific joint detail and does not extend to other details.
Remember this questions was specific to D1.1 and may not apply to other welding standards. I hope this helps, but it is only my opinion and my understanding of the question.
Best regards - Al