Posted on June-06-2026
Welding plays a critical role in modern industry, from construction and manufacturing to energy and infrastructure projects. For welds to be reliable and meet strict safety standards, they must follow clearly defined procedures. This is where Welding Procedure Specifications (WPS) come in.
A Welding Procedure Specification is a formal document that provides detailed instructions on how a welding process should be carried out. It outlines the materials, parameters, and techniques required to create a weld that meets specific quality and safety standards.
For companies working in sectors where structural integrity is vital, such as construction, pressure vessels, pipelines, and fabrication, following a WPS is not optional. It ensures that every weld is consistent, repeatable, and compliant with relevant standards.
In this guide, we will explain what a WPS is, why it is important, what information it contains, and how it benefits both welders and clients.
A Welding Procedure Specification (WPS) is a written document that describes how to perform a welding operation according to approved standards.
It provides welders with precise instructions on how to create a weld that will meet the required mechanical and structural properties. These instructions typically include details such as the welding process, materials being joined, filler metals, electrical settings, and welding positions.
The purpose of a WPS is to ensure that welds are performed in a consistent way, regardless of who carries out the work. By standardising the process, organisations can maintain quality, improve safety, and comply with industry regulations.
Many industries require a WPS to meet recognised standards such as BS EN ISO welding standards or other regulatory requirements. harmonized British (BS), European (EN), and International (ISO).
One of the biggest advantages of using a WPS is consistency. When welding parameters are clearly defined, welders can replicate the same results every time.
Without a documented procedure, welding quality can vary depending on the experience or interpretation of the individual welder.
A WPS removes this uncertainty by establishing a standard method for completing the weld.
Many industries must comply with strict welding codes and regulations. A properly developed WPS ensures that welding operations meet these requirements.
This is particularly important in industries where weld failures could lead to major safety risks, such as:
Structural steel construction
Pressure vessels
Pipelines
Shipbuilding
Energy infrastructure
Following approved welding procedures demonstrates that the work meets recognised safety and quality standards.
Welding involves high temperatures, electrical currents, and potentially hazardous fumes. A WPS helps reduce risk by outlining safe operating parameters.
It ensures that welders use appropriate techniques and equipment settings that minimise defects and prevent structural failures.
A WPS also acts as a reference guide for welders, especially those working on new materials or unfamiliar welding procedures.
It provides clear instructions that help welders understand exactly how the weld should be carried out.
A Welding Procedure Specification contains detailed technical information that guides the welding process.
While the exact format may vary depending on standards or company requirements, most WPS documents include the following elements:
The document specifies which welding method should be used.
Examples include:
MIG welding (Metal Inert Gas)
TIG welding (Tungsten Inert Gas)
Stick welding (Shielded Metal Arc Welding)
Flux-cored arc welding
Each process has different characteristics and is suitable for specific materials and applications.
A WPS identifies the materials being welded together. This includes the type of metal and its thickness.
Different metals require different welding techniques and settings to ensure proper fusion and strength.
In many welding processes, filler metal is used to join the base materials.
The WPS specifies the correct type of filler metal to use. Choosing the correct filler material ensures compatibility with the base metals and maintains weld strength.
The position of the weld can affect how the welding process is performed.
Common welding positions include:
Flat
Horizontal
Vertical
Overhead
A WPS will indicate which positions are permitted for the specific procedure.
The document also includes electrical settings such as:
Voltage
Current (amperage)
Travel speed
These parameters are essential for controlling heat input and ensuring the weld penetrates properly without causing defects.
Some materials require preheating before welding begins.
The WPS specifies the required preheat temperature and the allowable interpass temperature to prevent cracking and maintain structural integrity.
For processes such as MIG and TIG welding, shielding gas is used to protect the weld pool from atmospheric contamination.
The WPS identifies the type of shielding gas and the required flow rate.
When discussing welding procedures, you may also encounter the term Procedure Qualification Record (PQR).
Although the two documents are related, they serve different purposes.
A WPS provides the instructions for performing the weld.
A PQR is the record that proves the welding procedure works. It documents the results of testing carried out on a sample weld produced using the specified procedure.
During qualification, the weld sample may undergo tests such as:
Mechanical strength testing
Bend tests
Impact testing
Non-destructive testing
If the test results meet the required standards, the WPS can be approved for use.
By following a properly developed Welding Procedure Specification, many common welding defects can be avoided.
These include:
Porosity occurs when gas becomes trapped in the weld metal, creating small holes that weaken the weld.
Cracks can form due to improper heat control, unsuitable filler materials, or poor joint preparation.
This happens when the weld metal does not properly bond with the base material.
Undercutting occurs when the weld groove melts away the base metal but is not filled properly.
By clearly defining welding parameters, a WPS helps prevent these defects and ensures stronger welds.
Welding Procedure Specifications are used across a wide range of industries where structural integrity and safety are essential.
These industries include:
Construction and structural steel fabrication
Oil and gas pipelines
Aerospace manufacturing
Shipbuilding
Automotive production
Power generation
In many of these sectors, welding procedures must be approved before work can begin on critical components.
Professional welding companies use WPS documents as part of a broader quality assurance system.
This typically involves:
Developing welding procedures based on project requirements
Qualifying those procedures through testing
Training welders to follow approved procedures
Inspecting completed welds to ensure compliance
By implementing this structured approach, welding companies can maintain high standards of quality and reliability.
Welding Procedure Specifications (WPS) are an essential part of professional welding operations. They provide a structured and standardised method for carrying out welding work safely and effectively.
By defining welding parameters, materials, and techniques, a WPS ensures that welds are consistent, compliant with industry standards, and capable of meeting demanding performance requirements.
For industries where reliability and safety are critical, following approved welding procedures is key to maintaining quality and preventing costly failures.
