Weld Procedures & Welder Qualifications

Weld Procedure Specification (WPS)

A Weld Procedure Specification (WPS) is a formally written and controlled document that provides detailed instructions for carrying out welding activities in a consistent, repeatable, and compliant manner. Its purpose is to ensure that welded joints achieve the required mechanical properties, quality level, and service performance.

The WPS defines the approved welding parameters and conditions that must be followed by the welding personnel for a specific scope of work. Adherence to an approved WPS helps minimise variability, reduce the risk of defects, and ensure compliance with applicable codes and standards.

Purpose of a WPS

• Ensure welds are produced to a defined and qualified standard

• Provide clear instruction to welders and supervisors

• Control welding variables that affect weld quality

• Support compliance with contractual, regulatory, and inspection requirements

Typical Contents of a WPS

A WPS will typically include, but is not limited to:

• Base material specification and material group

• Joint design and preparation details

• Welding process (e.g. MMA, MIG/MAG, TIG, SAW)

• Filler material / consumable classification

• Preheat, interpass, and post-weld heat treatment (PWHT) requirements

• Welding position and progression

• Electrical parameters (current, voltage, travel speed)

• Shielding and backing gas details (where applicable)

• Number of passes and bead sequence

• Acceptance criteria and applicable standards

Qualification of a WPS

Before production welding can commence, a WPS must be qualified through welding trials. This is normally achieved by producing a Procedure Qualification Record (PQR), which documents the welding of a test piece under controlled conditions in accordance with the proposed WPS.

The test weld is then subjected to a range of destructive and non-destructive tests, which may include:

• Visual and dimensional inspection

• Radiography or ultrasonic testing

• Tensile testing

• Bend testing

• Impact testing (where required)

• Hardness testing

Successful completion of these tests demonstrates that the WPS is capable of producing welds that meet the required quality and performance standards.

Welder Qualification

In addition to WPS qualification, individual welders must demonstrate their ability to follow the approved procedure. This is achieved through a Welder Performance Qualification (WPQ or WPQR), where each welder produces a test weld using the qualified WPS.

The welder’s test piece is inspected and tested to confirm:

• Correct technique and parameter control

• Compliance with the WPS

• Ability to consistently produce acceptable weld quality

Only welders holding valid and in-date qualifications are permitted to carry out production welding under that WPS.

Role of NDT in WPS Compliance

Non-Destructive Testing plays a critical role in verifying compliance with a WPS during both qualification and production welding. NDT confirms that:

• Welds meet specified acceptance criteria

• No unacceptable internal or surface defects are present

• Welding processes remain in control throughout production

WHE NDT Support

At WHE NDT, we support clients with and provide;

• WPS review and verifications

• Witnessing of PQR and welder qualification tests

• NDT during procedure qualification and production welding

• Ongoing compliance and quality assurance support

Our involvement ensures that weld procedures, welder qualifications, and inspection activities are fully aligned.

Weld Procedure Approval Record - BS EN ISO 15614 2017

Qualification Testing of Welders - BS EN ISO 9606 2013

If you require any further information, please do not hesitate to contact info@whendt.co.uk.