Code is AWS D1.1:2000 Table 4.5 part 3.
Supplier provided a welding procedure/procedure qualification. GTAW process. PQR states electrode classification as "ER-70S-2". On the WPS the electrode classification is marked as "ER-70S-X". My opinion is that Table 4.5 part 3 would require a classification to be stated, in this case it would be the same as the PQR. If you changed to another electrode classification such as ER-70S-6 it would require requalification. Supplier doesn't agree. Any opinions out there?
ER70S-2 or -6, in GTAW, are not electordes. Tungsten is the electorde.
PWC
Thanks for the answers. I too have in the past just put 'X' on the WPS; however, there was enough doubt to ask. That brings up another question. If in GTAW the tungsten is the electrode then if the PQR is ran using a 2% thoriated electrode, then any change from that would require requalification?
...a change in one electrode classification to any other electrode classification.
Cameron is right. In GTAW the electrode is the tungsten. The problem is that Table 4.5 itself is in conflict by using the term electrode for the filler metal in variable 4. The X suffix is common in ASME procedures but not AWS. I also find it interesting that for GMAW the electrode classification IS NOT an essential variable requiring requalification in which case the ER70S-X WOULD BE the electrode. And this lends credibility to the argument that the X-suffix is acceptable for GTAW, the only variable being the AWS specification from variable 4, as with GMAW. Another way of saying this is that if you assume the X suffix is acceptable for GTAW you are consistent with GMAW and the idea that the tungsten is the electrode. If you claim the X suffix is NOT acceptable then you are in conflict with the variables for GMAW and the idea of the tungsten electrode for GTAW.
Also, since the brunt of the variables for GTAW are based upon variable 4 then the ER70S-X would again be acceptable since as soon as you say ER70-S whatever you are stating it is an AWS specification filler and addresses variable 4.
FYI:
If, when writing a WPS, the "X" (ER70S-6, ER70S-2) doesn't mater to me, I use ER70S-X all the time.
PWC
By 803056 
Date 07-20-2012 15:35
Edited 07-23-2012 12:29
Let's not confuse the difference between specification and classification.
AWS filler metal specifications are the A5.XX documents. The specification is a "family" of filler metals and/or electrodes. Example; AWS A5.18 includes filler metals that can be used with GTAW or PAW as a rod and the same filler metal can be used with GMAW as an electrode. All of the filler metals listed in AWS 5.18 are typically used to weld carbon and high strength low alloy steels.
The filler metal specification lists many different classifications, all of which are considered to meet the specification.
The specification is typically an essential variable, but the classification is usually a nonessential variable. Thus, a substitution of EWP in place of EWZr is usually a nonessential variable. A revision of the WPS is all that is needed because the substitution does not involve a change from one specification to another. Likewise, a substitution of ER70S-3 in place of ER70S-2 does not usually require requalification of the WPS because the change does not involve a change in the specification. i.e., both filler metals are containing in AWS A5.18.
The same cannot be said of a change that involves substituting one filler metal specification for another, especially if it involves a change in F-number, for example, the substitution of an E8018-B2 electrode in place of E6010. The E8018-B2 is listed in AWS A5.5 and is a F4 electrode. The E6010 is listed in AWS A5.1 and is a F3 electrode. The substitution involves a change in the specification, strength, one flux covering for another and different filler metal specifications. Regardless of what welding standard is being used, such a change is usually considered to be an essential variable and requires the WPS to be requalified.
The specifics of the particular welding standard or code will dictate when the change from on specification to another or from one filler metal classification to another requires requalification.
In the case of GMAW, whether the WPS lists ERXXS-SS is often dependent on how the WPS is to be used, i.e., when the WPS used for a broad variety of work or is the WPS job specific. When the WPS is job specific, I list one or two options, i.e., ER70S-2 or ER70S-6, because there are applications where it does make a difference, even if the difference is subtle.
Back to the original post; The PQR list a specific filler metal meeting the classification requirement of AWS A5.18. The WPS can utilize (i.e., list) any electrode classification contained in AWS A5.18 if the welding process is GMAW per item 1 in Table 4.5 (D1.1:2010) provided the change does not involve an increase in strength. However, this WPS is for GTAW and that being the case, item 3 states that a change in electrode or flux-electrode classification does require the WPS to be requalified. Once again, the specifics of the applicable welding standards comes into play. What is permitted by one welding code may not be permitted by another code. The poster hit the nail on the head in this case. This WPS is no longer qualified if a change in the filler metal classification is made. Go directly to jail, do not pass Go and do not collect $200.
After rereading the post I noticed the poster is citing D1.1:2000. I will have to go back to the 2000 edition to see if there is a revision, i.e., a difference, in the requirement between the 2000 and 2010 edition. Such a revision, if it is changed, is just the type of thing that can bite the inspector in the hind quarters.
Best regards – Al
