AWS D1.1 Prequalified WPS

Date 01-22-2002 02:08

Hi Tim:
The AWS D1.1 Code (nor any other Code which I know) doesn't give values about amperage, voltage, travel speed and shielding gas flow rates. You are right, the WPS's designer is who is in charge to define these variables in such way to assure the achievement of mechanical and physical properties of the joint and soundness and proper performance during the service, according the Code if it is required. You must use another sources in order to designe a WPS.

Jorge Giraldo
Medellín, Colombia

By TimGary (****)

Date 01-22-2002 12:07

I guess what I'm getting at is that AWS D1.1 makes every effort to imply that the prequalified WPS's in Section 3 are exempt from qualification testing (3.1) and go further to explain in C3.2.1 that certain process WPS's in conjunction with certain joint types have been thouroughly tested with a long reference and therefore are exempt from further testing. After all this they only provide a portion of the information needed to make up a complete WPS and don't provide any information as to where the WPS writer is to find the rest. They do imply in 3.6 however that any changes to essential variables require a new or revised WPS.
So, anyway, my question is that is all this talk in the Code about "Prequalified WPS's" double talk or am I missing something?
Tim

By CHGuilford (****)

Date 01-23-2002 14:57

D1.1 allows you to write a WPS nearly any way you want to...PROVIDED what you write will give good sound welds. It is pretty much up to the writer to determine what parameters will work. Even though 3.2.3 is referring to "other" processes, it gives some guidance by implying that "documented evidence" and /or results from a "series of tests" is already available for prequalified processes. And that usually is available for the asking from the electrode manufacturer as was pointed out by another post.

It's good to always keep in mind that someone has to read the WPS and make welds with the parameters listed. I know that sounds obvious, but if you're dealing with a new product for instance, it's wise to try it out. Manufacturer's data is written with customer appeal in mind. Make sure the least experienced welder can run it. Many times, WPSs are written to satisfy an approving engineer who wanted changes made, for whatever reasons, but the changes might make welding more difficult.

Really though, prequalified WPSs should have a range of parameters wide enough to cover the conditions. And they should be based on manufacturer's recommendations and your experience with the consumables. Later on, if a welding situation requires welding outside the WPS parameters, write a new WPS after you make sure you will still get good welds. The key is to do what you've written after you've written what you do.
CHGuilford

By kpauley (*)

Date 01-22-2002 12:41

When writing our Prequalified WPS's, I consult the manufacturer of the electrode for the parameters.

By John T. (*)

Date 01-27-2002 04:35

Hello Tim I don't think thats a dumb question at all, myself I would take the formula or the constants you know for sure and plug them in one by one using section 3 to back it up, anything that does not jive with section 3 is not prequalified. Hope thats not to vague and indirect, but thats how the D1.1 is designed, it covers a very broad spectrum.

By George-kh (**)

Date 01-27-2002 11:53

as Jorge Giraldo said, there is not any code and standard to sugest welding parameters.

I don't have D1.1 code now here. however, as I remember D1.1 doesn't let to use prequalification for GTAW & GMAW-S (DIP TRANSFER).

Best Regards