Hello Joe, Shane, et. all;
It is a holiday here in the US of A. Labor Day and I'm supposed to be kicking back and relaxing. Silly me, this is what I call relaxing.
“Will you suggest to use Fig 4.21 if the WPS is prepared for one side welding w/o backing or gouging of CJP Groove Welds for Nontubular Connections?
“So what Fig in D1.1 I can use to qualify a welder for qualification without backing / gouging of nontubular connections?
Fig 4.24 (A)? Who gives a rat's patut? ”
To your question with regards to procedure qualification; first, Figure 4.21. 4.22, and 4.30 (at least in the 2010 edition of D1.1) depict V-grooves (in plate) with backing which is to be used for welder performance testing. There are no provisions for removing the backing so the welder can back gouge the root. The visual acceptance criteria listed in clause 4.9.1 (5) (used for both welder performance and procedure qualification) states: "The weld root for CJP grooves shall be inspected, and shall not have any cracks, incomplete fusion, or inadequate joint penetration." I understand that to include fusion to the steel backing bar must be complete as well. With that, there should be no need or desire to back gouge and back weld.
Figures 4.24 A and 4.24B are applicable to welder performance qualification on tubular shapes. While the tests qualify the welder for production welds on shapes other than tubular, they are not applicable to testing the welder on plate. Following the thread back to clause 4.27, item (1) (paraphrased) states figure 4.24(B) can be used when the welder must be qualified for production joints that are backed or back gouged. Figure 4.24(A) is intended to be welded from one side, i.e., open root. Footnote “i” from Table 4.10 has provisions for production welds that must be back gouged, but it provides no provisions for back gouging the test assembly during the qualification test. Just because the test qualifies the welder for production welds that must be back gouged, it doesn’t mean the test assembly is back gouged. Remember, a welder that is qualified on a joint with backing is also qualified for production joints that will be back gouged (reference Clause 4.24)
If you are going to qualify a welding procedure, the WPS should stipulate the groove details. If you are qualifying a WPS for tubular joints, figures 4.25(A) or 4.25(B) can be used. Neither figure is intended for T, Y, or K connections between tubular members. AWS gives the fabricator free rein to design a joint anyway they want as long as the joint detail and the technique employed replicates what will be done in production and the variables listed in tables 4.1 and 4.5 are observed. Remember to separate the function of qualifying a WPS from the function of qualifying the welder.
As I have stated before, any code, AWS D1.1 included, stipulate the minimum requirements that have to be met. The contractor is responsible to take whatever additional steps are necessary to ensure the integrity of their work. Once the basic welder performance tests prescribed by AWS D1.1 have been administered and passed, the contractor can administer any additional tests or any design they deem necessary to ensure the welders have the skills required to function as a production welder.
Whether it is reasonable to presume the welder is the only person that will perform back gouging operation is open to discussion. I have been in a number of facilities where the welders do not perform the back gouging operations. With the presumption that it is the welder that will be back gouging the joint, the contractor is free to administer a butt joint test on plate or tubular shapes and he is free to include a requirement that the welder back gouge the root to sound metal and back weld the joint. The contractor can even define what process will be used to back gouge the joint. The contractor can stipulate the welder must use a 8 inch grinder, a rotary file, a carbon arc gouging torch, an oxy-fuel gouging torch, a hand file, or a chisel and hammer to excavate the root to sound metal. However, the requisite performances tests as defined by AWS D1.1 must be part of the performance testing program. It is not a requirement per D1.1 that the welder be qualified on a test assembly where back gouging is a requirement. Again, Clause 4.24 is clear, a welder that is qualified with backing is also qualified for grooves that are back gouged. There are no provisions however that state that a welder qualified with back gouging is also qualified to weld joints that incorporate backing.
With regards to Shane’s question regarding the qualification of a WPS, there is a difference in philosophy between AWS D1 structural codes and ASME Section IX. Whereas ASME includes the thickness of the weld deposit as a variable, AWS does not. That is the fly in the ointment. AWS qualifies the WPS based on the thickness of the base metal. ASME includes the thickness of the weld deposit as well as the thickness of the test assembly when determining the range for which the procedure is qualified.
As is this entire composition, this is simply my opinion on the subject. I believe there is a presumption on the part of the AWS D1 committee that the entire assembly is welded with one process and in one position. I see no alternative considering there is no mechanism. i.e., the thickness of the weld deposit, to separate the welding processes used, there is no mechanism to separate the different filler metal strength levels, whether the electrode is a low hydrogen type versus nonlow hydrogen type, variations in alloy content, etc. all of which are listed as essential variables in Table 4.5.
With that in mind, my opinion is that when the contractor is qualifying a welding procedure specification in accordance with D1.1, the entire test assembly must be welded with one welding process, in one test position (tubular sections being an exception), using one type of filler metal. If more than one welding process is to be employed in production, and if more than one filler metal type is to be used, if more than one welding variable listed in Table 4.5 or 4.6 (when applicable) is changed, a new test assembly must be welded and tested. Clause 3.6.1 is the code provision that permits the contractor to use more than one WPS to complete a production weld.
Having said all that I have to say, there are enough weasel words in the code that a determined contractor will worm his way around and through the code to do what has to be done. In the end the Engineer (representing the Owner, not the contractor) has sufficient latitude to allow variances from the code’s requirements to get the job done. If the contractor can get the Engineer’s blessing, anything is possible.
Shane, in consideration of your location relative to where I sit, your overheads are my flats and my flats are your overheads. I'm not sure why there should be any confusion.
Best regards - Al