WPQ

By TimGary (****)

Date 06-19-2019 12:13

In order to receive the best answer to your query, you need to identify the applicable welding code.

For a basic, general answer:

People often confuse essential variables from WPQ (Welder Performance Qualification) and PQR (Procedure Qualification Record).

The basis behind a WPQ is for the Welder to demonstrate the ability to follow a WPS (Welding Procedure Specification) for a specific welding process in order to make acceptable welds. The main concerns are joint type and position. Material differences are only considered in extreme differences, such as steel and aluminum.

The main Purpose of a PQR is to demonstrate that a chosen welding process, electrode and parameters combine to create a weld that meets or exceeds (to a certain extent) the mechanical properties of the base metal. In this, base metal type is more essential than welding position.

Tim

By Erick Arcos Date 06-28-2019 00:16 Edited 06-28-2019 00:54

Thank you a lot Tim,

Code that i am working is AWS D.1.1.

I was confused, but now i have other question: for example with the same code, i have a WPS(prequalified) with base metal of the second group (A572 GR 50) , can I use this wps(prequalified) for fabrication with same essential variables but with other base material but the same group(ASTM A588)? Can i use table 4.8 about base metal group combination?.

Greeting,

Erick

By TimGary (****)

Date 06-28-2019 12:12

Hello Erick,

For essential variables of pre-qualified procedures in AWS D1.1 : 2015, use table 3.7.
There you will see - "3) A change in base metal group number(s) (see Table 3.1) " as an essential variable.

So , the answer to your question is yes, the same PWPS may be used for base materials in the same Group.
However, you may not want to.
The difference between A572 and A588 is that A588 is a weathering steel with special alloying elements to provide a corrosion limiting patina, typically used where the weldment is desired to be left unpainted.
When this material is used, often a particular filler metal is used for patina color matching properties.
If this outcome is desired, a separate PWPS would also need to be used that lists the desired filler metal.
See this link for more info -
https://www.hobartbrothers.com/news/181/523/Welding-Weathering-Steels-Understanding-the-Material-and-Choosing-Filler-Metals-for-the-Job.html
And again, a separate Welder Performance Qualification (WPQ) would not be required, even if you made an ASTM 588 specific PWPS, unless there are changes in the joint types, positions or base metal thicknesses not covered under the original WPQ.

Tim

By jwright650 (*****)

Date 06-28-2019 14:55

to add to Tim's reply, the filler is pretty important when dealing with A588 if the filler material needs to color match (patina) and appearance. Single pass fillets may have enough dilution to color match fairly well, but multi-pass fillets and groove welds will need filler that matches closer.

By Lawrence (*****)

Date 06-19-2019 16:59

If your question is related to AWS D1.1 (2015)

See table 4.12

You have done a pretty good job of translating your question into English, but if this table is not what you are looking for, say a little more about your question.

By Erick Arcos Date 06-28-2019 00:41 Edited 06-28-2019 00:53

Thank you for answering me, yes, my question is related with AWS D1.1(2015) I was confused, I thought that the metal base is essential variable for the WPQ, i'm doing the Dossier of a building and i have some WPQ with ASTM A 36 as base metal but belong to the group 1 and was going to requalification welders, because I'm working with ASTM A 588 as base metal.

Greetings,

By 803056

Date 06-28-2019 10:37

The welder can qualify using any of the listed steels found in D1.1. As a matter of fact, qualification to D1.1 on carbon steel even qualifies the welder for austenitic stainless steel if the F number isn't changed per AWS D1.6!

Al