What Are WPS, PQR, and WQTR? A Beginner's Guide

For welders and fabricators new to formal project work, three terms keep showing up in project documentation: WPS, PQR, and WQTR. They're related, but each serves a different purpose. Understanding the difference matters — both for passing QC inspection and for understanding why a welding procedure is defined the way it is.

WPS — Welding Procedure Specification

A WPS is a document that describes how a weld must be performed. It covers parameters such as the welding process (SMAW, GMAW, etc.), base material type and thickness, welding position, electrode or filler metal type, preheat temperature, and the allowed current and voltage ranges.

In short, a WPS is a recipe. The welder performing that joint is required to follow the parameters written in the WPS — not improvise their own approach, even if they're technically capable of welding it another way.

PQR — Procedure Qualification Record

If a WPS is the recipe, a PQR is the proof that the recipe has been tested and shown to produce a weld that meets requirements. A PQR is created by actually welding a test piece according to the proposed parameters, then subjecting the resulting weld to destructive testing (such as tensile and bend tests) to confirm its strength and quality meet the applicable standard.

Only once the PQR passes is the associated WPS considered "qualified" and acceptable for use on a real project.

It's worth noting that not every WPS needs to go through full PQR testing. Some codes (AWS D1.1 for structural steel, for example) recognize the concept of a prequalified WPS — a combination of parameters already considered proven by industry experience, which doesn't require new PQR testing as long as every parameter stays within the ranges defined by the code.

WQTR — Welder Qualification Test Record

Unlike a WPS and PQR, which test the procedure, a WQTR tests the person. A WQTR is the record of a welder's test results, proving they have the skill to weld according to a given WPS and produce results that meet the standard.

A welder qualified under a WQTR for one combination of process and position isn't automatically qualified for a different combination. This is why professional welders often hold several WQTR certificates covering different processes and positions.

How the Three Connect

The typical sequence runs like this: a company drafts a WPS, that draft is tested and the results recorded as a PQR (or referenced against a prequalified WPS where the applicable code allows it), and the welder assigned to the job must hold a WQTR matching that WPS. Together, the three form layered quality assurance — not just paperwork.

Why This Matters Early On

Understanding these three documents isn't just about clearing project paperwork. It also helps you understand why a welding procedure is set up the way it is, rather than just following numbers without knowing the reason. Welders who understand the logic behind a WPS tend to adapt faster when field conditions introduce variation.

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Note: this article is a general introduction and not a substitute for the official code governing your project (such as AWS D1.1, ASME Section IX, or ISO 15614). Always ensure WPS, PQR, and welder qualification documents on real projects are reviewed and approved by a Welding Engineer or other authorized party as applicable.