What does WPS mean in welding—and how does it relate to lifting accessories?
In welding, WPS refers to a welding procedure specification that defines the materials, preparation method, welding process, filler materials, and welding parameters for a specific welded joint. The abbreviation WPS stands for Welding Procedure Specification.
Simply put, the WPS tells the welder how to weld the joint in a controlled manner and in accordance with the requirements.
In short: A WPS is a set of instructions for welders that specifies how a particular weld is to be performed. A WPQR, on the other hand, indicates the criteria on which the welding procedure has been approved. For lifting accessories, an approved welding procedure is a key part of safe and traceable manufacturing.
The importance of WPS is particularly evident in safety-critical structures, such as lifting accessories. The revised SFS-EN 13155 standard requires the use of an approved welding procedure specification in the manufacture of lifting accessories, and when the EU Machinery Regulation (2023/1230) enters into force on January 20, 2027, compliance with the new version of the standard will become mandatory.
What does WPS mean in welding?
A WPS is a written work instruction used in production. It ensures that welding is performed in a planned and repeatable manner, regardless of which qualified welder carries out the work.
A WPS is not a general guide to good welding. It is prepared for a specific welding procedure and a defined scope of qualification. A single WPS may cover several similar joints, materials, and material thicknesses, provided they fall within the scope of the approved welding procedure.
WPS can be compared to a recipe: it specifies the necessary materials, work steps, and permissible values according to which the welding is performed.
What information does WPS contain?
For arc welding, the technical content of the WPS is covered in the SFS-EN ISO 15609-1 standard. A welding procedure specification may include, for example:
- Base materials to be welded and material thicknesses
- the welding process to be used
- the shape of the joint and the groove
- welding position and welding sequence
- welding consumables and shielding gases
- Permissible ranges for current, voltage, and welding speed
- preheating and intermediate barrel temperature
- a reference to the WPQR approval protocol or another approval document.
If a lifting accessory is manufactured, for example, from structural steel using MAG welding, the WPS may specify—in addition to the welding wire and shielding gas—the permissible welding parameters, welding position, and temperature limits. The welder therefore cannot freely choose these values during the work process.
What do pWPS and WPQR mean?
pWPS stands for “preliminary welding procedure specification.” It defines the planned welding procedure prior to its approval.
Once the method has been approved as appropriate, a WPS for use in production is prepared.
pWPS → Approval of the welding procedure → WPQR → WPS used in production
WPQR is an abbreviation for “Welding Procedure Qualification Record.” SFS-EN ISO 15607 uses the Finnish term “hyväksymispöytäkirja” for it.
The WPQR documents the basis on which a welding procedure has been approved and the scope of its application. Approval may be based, for example, on a welding procedure test, tested welding consumables, documented prior welding experience, or another appropriate procedure. The approval method to be used is determined by the applicable requirements.
The difference can be summarized as follows:
WPS specifies how to weld. WPQR indicates the basis on which the welding procedure has been approved.
Does WPS guarantee the quality of the weld?
WPS lays the foundation for welding that meets the requirements, but it alone does not guarantee the quality of the finished weld joint.
Quality is also influenced by:
- welding technician or welding operator certification
- the suitability of materials and welding consumables
- working conditions
- Compliance with WPS
- monitoring of the manufacturing process and inspection of welds.
Furthermore, a WPS does not replace a welder’s qualification. A WPS specifies the welding procedure to be used, whereas a welder’s qualification demonstrates the individual’s ability to perform that type of welding to an acceptable standard.
A safety-critical structure requires both an approved welding method and a welder qualified to perform it.
WPS Welding and the Manufacture of Lifting Accessories
The welded joints of a lifting accessory may be subjected to high and repeated loads. In the worst-case scenario, damage to a joint could cause the load to fall, resulting in a serious hazardous situation.
The appearance of a weld alone does not indicate the strength of the joint. The properties of a weld are influenced by factors such as the base material, filler material, heat input, temperatures, joint geometry, and welding sequence.
An approved WPS helps ensure that welding is performed using a predefined and documented method. At the same time, it ensures that the manufacturing process is repeatable and traceable.
The welding procedure approved in the revised SFS-EN 13155 standard is part of the controlled manufacturing process for lifting accessories. It is also important to take this requirement into account when a company manufactures lifting accessories for its own use and thus acts as the manufacturer of the accessories.
What should the person ordering a lifting accessory make sure of?
When purchasing a welded lifting accessory, you should make sure that:
- The equipment is designed according to its intended use and actual loads
- The structural strength has been verified
- Approved welding procedures and qualified welders are used in the manufacturing process
- The materials and manufacturing process are traceable
- Manufacturing and inspections are documented
- The device comes with the necessary labels, user instructions, and conformity documentation.
A safe lifting accessory is the result of a comprehensive process consisting of design, strength verification, controlled manufacturing, inspections, and documentation.
Lifting Accessories: From Design to Implementation
Hefmec designs and supplies custom lifting accessories to meet a variety of industrial needs. We handle the entire process, from design and structural analysis to controlled manufacturing and compliance documentation.
When you need a safe lifting accessory designed specifically for your application, please contact our experts.
Written by Simon Hindersson, Mechanical Designer and Sheet Metal Welder
This article is a general overview, not a binding guide to applying the standard. It is always advisable to check the specific requirements in the current version of the standard and on a case-by-case basis.
