Q 1: Is it required to certify a WPS?<\/strong><\/p>\n\n\n\nNo. While Section IX does require certification of PQR and WPQR records by a competent authority, no such requirements have been specified for WPSs. However, most organizations still choose to approve the WPS document (generally by the welding engineer). This is done so that the authenticity of the document does not come under any doubt on the shop floor.<\/p>\n\n\n\n
Q 2: Who can approve a WPS?<\/strong><\/p>\n\n\n\nSection IX does not address this. Any competent authority designated in the organization\u2019s quality program can approve a WPS.<\/p>\n\n\n\n
Content of The Document<\/h3>\n\n\n\n
Q 3: What should be the content of a WPS?<\/strong><\/p>\n\n\n\nThe WPS must address, as a minimum, all essential and non-essential variables related to the welding process proposed to be used. The WPS must address supplementary essential variables too, when toughness is a consideration.<\/p>\n\n\n\n
Any other additional information that the welding engineer feels is important to make a good weld can be included as well.<\/p>\n\n\n\n
Q 4: Is it okay to not address non-essential variables on a WPS?<\/strong><\/p>\n\n\n\nNo, it is not okay to not address non-essential variables on a WPS. Section IX makes it clear at multiple places that a WPS must<\/em> address all essential and non-essential variables pertaining to that welding process. This has been further regurgitated in a few interpretations as well.<\/p>\n\n\n\nHowever, in the recent editions (I think from 2019 edition onwards), a sentence appears at QW-101, which states that when a variable is outside the scope of WPS, or is addressed by another variable, that variable need not be specifically addressed on the WPS or PQRs that support that WPS.<\/p>\n\n\n\n
For example, QW-410.64 is an essential variable that becomes applicable only when P-No. 11A or 11B are being welded. If a WPS is written for other P-numbers than these two, then this variable does not have to be addressed on the WPS.<\/p>\n\n\n\n
Likewise, QW-404.23, which says that a change in filler metal product form (that is, solid wire, composite, etc.) is an essential variable. If the WPS has specified ER70S-A1 GTAW filler, The \u2018S\u2019 in the filler designation automatically indicates that the filler is a solid wire. In such cases too, Section IX intends that the variable does not have to be specifically addressed on the WPS (since it is addressed elsewhere).<\/p>\n\n\n\n
Q 5: Is leaving a blank an acceptable method of addressing a variable on a WPS?<\/strong><\/p>\n\n\n\nNo, leaving a blank is not an appropriate method of addressing a variable. Although this has not been explicitly told anywhere in Section IX, understanding to this effect appears in a couple of interpretations.<\/p>\n\n\n\n
When a variable is not applicable, it is best to address it with a \u2018NA\u2019 or \u2018not applicable\u2019, etc. For example, if a WPS is qualified without any PQHT, the QW-407.1 field should not be left blank on the WPS. In its stead, \u2018none permitted\u2019, or \u2018none\u2019, or \u2018as welded\u2019, or \u2018no PWHT permitted\u2019 may be mentioned.<\/p>\n\n\n\n
Q6: Is it required to indicate limits of welder<\/em> qualification on the WPS?<\/strong><\/p>\n\n\n\nNo. The thickness limits on the WPS get dictated only by QW-451 (which is for procedure qualification), and not by QW-452 (which is for performance qualification).<\/p>\n\n\n\n
A welder may or may not be qualified to weld on the thickness limits specified on the WPS. There should be a separate mechanism to ensure that only suitably qualified welder(s) get deployed on the job. WPS is not that mechanism.<\/p>\n\n\n\n
Some companies however, choose to specify the welder qualification ‘tag number’ on the WPS. This indicates to the production engineer which welders are qualified to use that WPS. There is nothing wrong with this practice. Though, this is not a mandatory requirement of Section IX.<\/p>\n\n\n\n
Use of WPS Qualified to Earlier Editions of Section IX<\/h3>\n\n\n\n
Q 6: Can we use the WPS\/ PQR qualified to an earlier edition of Section IX for a fabrication that specifies compliance to the latest edition?<\/strong><\/p>\n\n\n\nYes, the WPSs\/ PQRs\/ WPQRs that were made to any edition as far back as 1962 edition may be used for fabrication activities for which the current edition has been specified.<\/p>\n\n\n\n
Procedure qualifications and performance qualifications made before<\/em> the 1962 edition also can be used for activities for which the current edition has been specified, provided<\/em> the requirements of 1962 or any later edition have been met.<\/p>\n\n\n\nWPSs\/ PQRs \/ WPQRs meeting the above requirements do not need to be amended to include any variables required by the later editions, and can be used as it is.<\/p>\n\n\n\n
However, conducting a new<\/em><\/strong> procedure qualification today needs to be compulsorily done in accordance with the current edition of Section IX.<\/p>\n\n\n\nThese requirements have been specified at QG-108 (in the present day edition). The intent of this liberty is to avoid any extensive retesting of previously qualified WPQRs. Interpretation IX-83-148 presents an interesting example in this context.<\/p>\n\n\n\n
Note<\/strong>: Interpretation IX-78-32 tells us that a WPS can be written to the present day edition requirements with the support of a PQR qualified to a previous edition, provided all essential & non-essential variables of the present edition are satisfied. This is a very useful interpretation, and finds frequent use for writing day-to-day WPSs with the support of old PQRs, while proclaiming compliance to present edition.<\/p>\n\n\n\nMiscellaneous<\/h3>\n\n\n\n
Q 7: Can a welder use current, voltage (or any other parameters) outside of the range specified on WPS, if he feels the range given on WPS is not workable\/ infeasible\/ not the most correct etc.?<\/strong><\/p>\n\n\n\nNo. A welder must follow the WPS under all conditions. If a welder is found to be not following the WPS, it is a violation, and attracts a non-conformance report.<\/p>\n\n\n\n
If, due to any reason, the welder is unable to follow the parameters given on WPS, or feels that it is rightfully required to use parameters that are outside<\/em> of the range specified on WPS, he must bring it to the notice of his supervisor, who informs it to the welding engineer.<\/p>\n\n\n\nWhen the change desired is in any of the non-essential variables, the welding engineer can simply editorially amend the WPS (or issue a new one) and reissue the WPS. If a change is desired in any of the essential variables, then a new procedure qualification must be carried out with the changed parameters.<\/p>\n\n\n\n
When the new PQR is qualified, only then the WPS containing the new changes can be issued to shop.<\/p>\n\n\n\n