Last Updated on November 25, 2022 by mdmtool
In the welding industry, welders should know two important documents: Welding Procedure Specification (WPS) and Procedure Qualification Record (QPR). WPS and PQR are significant in producing good-quality of welds.
The main difference between these two documents is that a PQR is used to qualify a welder or welding operator for a specific welding procedure. In contrast, a WPS ensures that a welder or welding operator has the necessary information to safely and effectively weld a joint.
What Is WPS?
Welding Procedure Specification (WPS) is a written document that provides direction to the welder for making sound and repeatable welds.
What Is PQR?
Procedure Qualification Record (PQR) is a document that provides evidence that a welding procedure produces acceptable welds. A PQR is typically used to qualify a welder or welding operator for a specific welding procedure.
A PQR can also qualify a welding procedure for a specific welding application. For example, a PQR can allow a welding procedure for a particular material thickness or an exact position (horizontal, vertical, etc.).
Difference Between WPS And PQR
Contents
- WPS includes information such as the welding variables, base metal identification and composition, filler metal identification, heat input data, post-weld heat treatment (if applicable), and mechanical test results.
- PQR only provides evidence that a welding procedure produces welds of acceptable quality under the requirements of a code or standard.
Orientation
- WPS is oriented towards the welder, telling the welder what materials to use, how to set up the welding equipment, and what welding procedures to follow.
- PQR is oriented towards quality assurance, proving that a welding procedure produces welds of acceptable quality.
Approval
- A qualified welding engineer or supervisor must approve WPS.
- PQR must not be approved but must be reviewed by a qualified welding engineer or supervisor.
Frequency
- WPS should be updated as needed, for example, when new materials or welding processes are introduced.
- PQR does not need to be updated often but should be reviewed periodically to ensure that it is still valid.
Validity
- The validity of a WPS expires when the conditions specified in the WPS are no longer met.
- The fact that a PQR expires when the welding procedure or materials used in the PQR are changed.
Purpose
- A WPS’s goal is to guide the welder to help them produce sound and repeatable welds.
- A PQR aims to prove that a welding procedure has welds of acceptable quality.
Usage
- Welders should use WPS during the welding process.
- PQR should be used by quality assurance personnel to verify that a welding procedure produces acceptable welds.
Document Status
- WPS is a working document that is subject to change.
- PQR is a record of a past welding procedure and is not subject to change.
Place Of Use
- WPS is used in the shop or field.
- PQR is used in the office.
Benefits Of Using WPS And PQR
- Improve weld quality
- Optimize welding processes
- Support welder qualification
Overview Of WPS And PQR
- WPS is a format for describing welding procedures, while PQR is a quality control record used to qualify welding procedures
- Both are used to optimize welding processes and improve weld quality
- PQR requires more information than WPS, including details about the base metal, electrode type and diameter, welding current and voltage, travel speed, and shielding gas
- PQR also needs to be completed by a certified welding engineer
- WPS can be used as an input for PQR
- Both WPS and PQR can be used to support welder qualification
FAQs
Who Should Be Involved In Creating Or Approving A WPS Or PQR?
The welding engineer or supervisor should be involved in creating or approving a WPS or PQR. Additionally, the welder performing the welding should be qualified by the procedure specified in the WPS.
Why Are WPSs And PQRs Important?
WPS and PQRs are important because they guide how to produce sound welds that meet the required standards.
What Is A Prequalified WPS?
A prequalified WPS is a welding procedure specification reviewed and approved by the American Welding Society (AWS). This type of WPS can be used without further review or qualifications if it meets the project requirements.
What Is The Purpose Of The WPS And PQR To Determine?
The WPS and PQR determine the welding parameters used during welding, such as voltage, amperage, and travel speed.
Conclusion
The WPS and PQR are two essential documents that must be reviewed and approved before welding can begin. The WPS defines the welding framework used, while the PQR verifies that these parameters will produce a high quality weld.
