API 687 Chapter 0: Definitions (conclusion) – Welding terms: PQR, WPS, and WQR

We have finally reached the end of the definitions in API 687 Chapter 0. Out of the 41 definitions, I have chosen to focus on 10 terms and concepts which today include some important acronyms about welding.

You can spot metallurgists or welding engineers visiting a rotating equipment repair shop by the sounds they make. Some of those sounds will be the acronyms “PQR, WPS”, and sometimes their songs will contain a hint of “ASME Section IX” or “Boiler Code”.

All these beautiful words are part of a tradition that began in 1911 inside the halls of the American Society of Mechanical Engineers (ASME).

By the early 1900s, the Industrial Revolution that began in Great Britain and Europe is beginning to catch up in America, particularly the use of steam engines and steels.

As engineers push the boundaries of harnessing the energy stored in steam, due to the lack of standards and controls in the process of design and manufacturing, some catastrophic lessons are learned.

Think of the founding engineers of the ASME as the original Avengers. Find the smartest and handsomest engineers, inspired by the tragedies of boiler explosions that set out to define the standards that ensure safety and reliability when working on pressure-containing machines.

These standards are embraced to this day, particularly the ASME Boiler and Pressure Vessel Code (BPVC). The first boilers and pressure vessels were fabricated with rivets, but it is when welding technology is adopted in manufacturing that the ASME BPVC Section IX is created.

Known as Section IX for short, this is the document that defines the standard processes for qualifying weld procedures and for qualifying the welders that will perform said welds.

I always explain this in terms of cooking.

Anyone can do a Google search and find a recipe for anything, or a weld procedure to weld anything to anything.

But having a copy of a welding procedure does not guarantee that it can produce the desired results or that the welder using it has done it before and achieved good results.

The process established by Section IX helps certify and verify that both the recipes and the welders are effective.

Weld Procedure Specification (WPS)

The WPS is a recipe, actually more than just a recipe. It is a comprehensive document that outlines all the necessary parameters and procedures to ensure the consistent application of a welding process.

This document is formally known by the ASME as FORM QW-482.

The ASME is gracious to provide us with an official Adobe form following this link:

https://www.asme.org/wwwasmeorg/media/resourcefiles/aboutasme/who%20we%20are/bpvc%20resources/section_ix/bpvc_ix_qw-482.pdf

The document has the following structure:

General Information

Begins with document control. It has a unique identifier (WPS Number), a title, a revision number, and a date.

Since recipes can change, it is extremely important to keep discipline in the revision control process.

Base Materials

Details the information about the materials being welded, dimensions, and includes a description of the joint type.

Welding Process

Specifies the process and techniques being used. For example, Submerged Arc Welding, TIG, MIG, etc., including which gases will be used for shielding.

Filler Material

Details the filler metal used down to its composition.

Welding Parameters

Basically, all the settings for the welding machine and guidance for the welder/operator according to the process that was selected.

Preheat, Interpass Temperature, and Post-Weld Heart Treatment (PWHT)

These are all pre, during or post processes where heat is applied to the part; how to prepare it, maintain adequate conditions, and heat treat the part once the welding is done.

A WPS specifies not only how to cook but how to prepare, present, and cleanup afterwards.

Procedure Qualification Record (PQR)

Once a WPS is dreamed up and written, it is time to qualify it.

A PQR contains all the test results of an executed PQR and a record of all the variables used.

This may require several trials, and one will choose the best or most experienced welder when attempting to qualify something new.

What is important to know is that, in a recipe, you may be given parameters in sets of ranges.

Therefore, a PQR is a way to hone in on which parameters produce the best results.

The ASME officially calls PQRs “FORM QW-483” and you can find their Adobe form here:

https://www.asme.org/wwwasmeorg/media/resourcefiles/aboutasme/who%20we%20are/bpvc%20resources/section_ix/bpvc_ix_qw-483.pdf

Welder Qualification Record (WQR)

The Welder Qualification Record or more officially known to the ASME as the Welder Performance Qualification (WPQ).

This is sort of the test and license to weld an individual would receive. It is a record that a welder was tested and was able to produce welds that meet the requirements specified in a WPS.

Remember, ASME’s official name for this is Welder Performance Qualification (WPQ) or FORM QW-484A and the Adobe form by the ASME can be found here:

https://www.asme.org/wwwasmeorg/media/resourcefiles/aboutasme/standards_certification/bpvc%20data%20forms/bpvc_ix_qw-484a.pdf

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Metals are susceptible to temperature, and their structure can be greatly affected during a weld.

That is why the ASME established Section IX, to standardize the process to dream, design, execute, and qualify welds and welders.

So, if you are considering welding as a repair or manufacturing method, please ask for all three.

Make sure whomever you are working with has a good understanding of the process and the metals being used.

Understand the purpose of the weld and the form and function of the parts affected.

Is it a structural weld or a buildup on a low stress part?

And then make sure whoever is actually going to perform the weld has a current PQR to demonstrate their capability to work within the requirements of the recipe and can produce a good weld.