The code lists the minimum requirements for the content of a WPS, variables to be recorded on a
PQR, etc.
Most codes are developed by old codgers that haven't welded in at least 20 years, if ever, and can't fathom how these new fangled machines work. What you don't understand, ignore.
Al
My input would be to include frequency and balance control ranges, plus current ranges on each side of the AC half cycle into your WPS if your equipment is capable of manipulating those factors.
And, if your power supplies are capable, make presets for various WPS's and lock them.
Of course this means training your welders so that they understand what they are doing then they push the buttons and turn the knobs.
My input would be to include frequency and balance control ranges, plus current ranges on each side of the AC half cycle into your WPS if your equipment is capable of manipulating those factors.
And, if your power supplies are capable, make presets for various WPS's and lock them.
Of course this means training your welders so that they understand what they are doing then they push the buttons and turn the knobs.
When you are making airplane parts, welding is a science, not an art.
Maybe new WPS formats for D1.2 will have a wave forms and hertz tab and the essential variables will account for change in hertz. For now I shall include as much information as possible. We are using Dynasty 350's and some of the guys prefer to run upwards of 160 Hertz, and some around 90.
Would the same apply to a welder qualification?
J
By Lawrence 
Date 03-22-2016 18:00
Edited 03-22-2016 18:05
You can make your WPS's as precise as you like my friend. Just not less precise than D1.2
For AC GTAW, frequencies in excess of 120 Hz only benefit in trigger migraines. (opinion only)
For Welder qualification, WPS/instructions of course need to be within the scope of the PQR, anything you add within the scope to improve the chances of passing is just good practice in my opinion.
Edit:
Example:
I would make 120hz a WPS mandatory condition for all aluminum fillets. But for doing a build-up for a broken lug on an aluminum casting I might want only 60hz to widen the puddle and reduce the directionality of the arc (wider bell). This would also apply to Magnesium castings welded with AC.
I believe the frequency is not an essential variable in AWS D1.2, but as it was mentioned by some other users, you can restrict your WPS to have stricter requirements than what AWS D1.2 states.
Since you are responsible for the product you provide your client, the fact that you create your WPS with stricter requirements assures the quality of your work even more than just using AWS D1.2's requirements. I do not have much experience with aluminum but if the frequency is something that is really relevant to its welding, I believe you should use that remark in your WPS, since you know what parameters will get you the best welds
Best Regards
My WPSs and supporting PQRs include more information than required by the code. I include all additional data I believe is useful.
I try to keep in mind that the WPS should provide the welder with sufficient information to set the machine and deposit sound welds that are compliant with the requirements of the code. That means, in the case of ASME, the requirements of Section IX as well as the requirements imposed by the construction code are met. In the case of D1.1, the WPS must include the information required by clause 3 for prequalified joints or clause 4 for WPSs qualified by testing, as well as the additional requirements of clause 5 and clause 2 when they apply. For instance, prequalified plug and slot welds have to comply with the dimensional requirements of clause 2, backing must be attached, tabs must be used as per clause 5. If the information isn't provided by the WPS the contractor must provide the information by some alternate means.
If the welder is using a machine that has pulsing capability, that information, i.e., machine parameters needed to pulse, should be included in the WPS. It may not be required by the code, but it is information needed by the welder so acceptable welds are deposited on a consistent basis.
Best regards - Al
