What is a Welding Procedure Specification (WPS)? Types & Importance

Updated: 20 Jan 2024

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A Welding Procedure Specification (WPS) serves as a significant document in the world of welding, providing a systematic and detailed outline for performing welding tasks. This essential document describes the specific parameters, materials, and techniques required to achieve standard and high-quality weld joints.

In other words, a WPS plays a crucial role in ensuring compliance with welding industry standards. In this exploration, we will understand the fundamentals of welding procedure specification and why it is important in the world of welding.

Table of Content

What is a Welding Procedure Specification (WPS)?

A Welding Procedure Specification (WPS) is a comprehensive document that gives detailed instructions on how to perform a specific welding operation. It serves as a guide for welders, ensuring uniformity and consistency in the welding process.

The WPS outlines the necessary steps, parameters, and conditions to produce a weld that meets the desired quality and performance standards.

Specification form of welding procedure (WPS) — Source: https://www.ohiogasassoc.org/

Why Do You Need WPS?

You must need WPS if you are in the welding field, and the following points will clear your idea about WPS;

Ensuring Consistency and Quality in Welded Joints
Consistent Production of Identical or Similar Welds
Prioritizing Safety in Welding Operations
Meeting Industry Codes, Standards, and Regulations with WPS
Testing and Verifying Integrity to Meet Required Standards
Facilitate Understanding Among Stakeholders in Welding Projects
Identifying and Resolving Issues to Maintain Welding Quality

Types of WPS:

There are many types of WPS, but two are the main types, which are given below.

1. Preliminary Welding Procedure Specification (pWPS):

The preliminary WPS is an initial document that defines the basic welding parameters and procedures for a specific welding job. It serves as a starting point before undergoing the entire qualification process. This type of WPS is beneficial during the early stages of a project or when developing new welding procedures.

welding procedure specifications enabling works (WPS) — Welding Project Enabling Works

2. Qualified Welding Procedure Specification (qWPS):

The qualified WPS is the final, fully approved document that has undergone the necessary welding procedure qualification tests. These tests demonstrate that the welding procedures specified in the document consistently produce welds meeting the desired quality and performance criteria.

Once a WPS has successfully undergone the qualification process, it is considered qualified, and welders can use it as a reference for actual welding work.

Additional Variations and Considerations:

These are additional variations (not main types) and considerations of welding procedure specification.

1. Joint-Specific WPS:

This type of WPS focuses on specific joint configurations. Different joints (e.g., butt joint, filet weld) may require unique welding procedures due to variations in geometry, stress distribution, and welding positions.

2. Material-Specific WPS:

WPS can also be categorized based on the materials being welded. For example, welding procedures for carbon steel may differ from those for stainless steel or aluminum. Material-specific WPS accounts for variations in material properties, composition, and thickness.

3. Industry-Specific WPS:

Specific industries have their standards and codes that give order to welding procedures. For instance, WPS developed for aerospace, automotive, construction, or oil and gas industries will adhere to industry-specific regulations and requirements.

Structural Code Books of Welding Procedure Specification for Steel and Titanium (WPS) — Structural Code Books for Steel & Titanium

4. Repair WPS:

A specialized repair WPS may be developed when welding is required for repair or maintenance purposes. This document considers the existing conditions and has specific requirements to ensure the repair weld meets the necessary standards.

5. Automated Welding WPS:

With the increasing use of automation and robotic welding systems, WPS can be adapted for automated processes. This includes specifying parameters and sequences suitable for automatic welding equipment.

Components of a WPS:

A WPS typically consists of several key components, each providing specific details about the welding process. The main components include;

Welding Procedure Number (WPN): Allowing easy referencing and tracking.
Base Metal Specifications: Detailed information about the welded materials, including type, grade, and thickness.
Joint Design: Specifies the configuration of the joint, such as the butt joint, fillet weld, or groove weld.
Welding Position: Defines the positions in which welding is to be performed (e.g., flat, horizontal, vertical, overhead).
Welding Process and Technique: Specifies the welding process (e.g., gas metal arc welding, shielded metal arc welding) and the technique to be used.
Welding Parameters: Includes essential parameters like current, voltage, travel speed, and preheat temperature, ensuring repeatability and consistency.
Consumable and Shielding Gas: Details the type and specifications of welding consumables (e.g., electrodes, filler wires) and the type of shielding gas used.
Welding Sequence: Provides a step-by-step guide on how welds should be performed to achieve the desired results.
Heat Treatment Requirements: Specifies any post-weld heat treatment processes that may be necessary for specific materials or applications.

Importance of WPS:

Ensures that welding processes are carried out consistently, reducing the chance of defects or structural weaknesses.
Helps adhere to safety standards by defining the necessary precautions and procedures to reduce potential hazards.
Enables compliance with industry codes and standards, ensuring the welded structures meet specific regulatory requirements.
Provides a documented record of welding procedures, allowing for traceability and easy auditing.
It is a valuable tool for training new welders and certifying their qualifications.

WPS in Different Industries:

Welding Procedure Specifications (WPS) are utilized across various industries to ensure standardized and quality welding processes. Here is how WPS is applied in different sectors.

1. Construction and Infrastructure:

In constructing buildings, bridges, and other infrastructure, WPS ensures that welded connections meet structural and safety requirements.

2. Oil and Gas:

WPS is crucial in the fabrication of pipelines and oil rig structures. Stringent standards are often imposed to ensure the integrity of welds in harsh environments.

3. Aerospace and Automotive:

Precision and reliability are crucial in aerospace and automotive applications. WPS is vital in producing welds that meet strict quality and safety standards.

4. Pressure Vessels and Boilers:

Welding in pressure vessels and boilers requires adherence to specific codes to ensure the welds can withstand high-pressure conditions. WPS guides the welding process in these critical applications.

WPS and Welder Qualification:

1. Procedure Qualification Record (PQR):

A companion document to WPS, the PQR records the results of the procedure qualification tests, providing evidence that the welding procedure meets the required standards.

2. Welder Performance Qualification (WPQ):

Before a welder is allowed to work on a project, they must undergo a performance qualification test using the WPS. This ensures that the welder can consistently produce welds meeting the specified criteria.

3. Certification and Compliance:

Successful completion of the WPQ allows welders to be certified for specific welding procedures, demonstrating their ability to work in compliance with industry standards.

FAQs:

What is the ISO for Welding Procedure Specification?

The ISO standard for WPS is ISO 15614. This standard provides guidelines for qualification welding procedures for metallic materials, ensuring consistency and quality in welding processes.

Who writes the WPS?

The WPS is typically prepared by a qualified welding engineer or a welding professional with expertise in a particular project’s specific welding processes and materials. The individual responsible for creating the WPS needs to have a good understanding of welding codes, standards, and the project’s particular requirements.

Who uses the information in a WPS?

Engineers, welding inspectors, and welders are among the key stakeholders who refer to the WPS for guidance on specific welding requirements and parameters in a given project.

How does a WPS support troubleshooting in Welding?

In case of welding issues, the WPS serves as a reference, helping to identify potential causes and solutions and aiding in the troubleshooting process.

Is a WPS required for all Welding Projects?

The necessity of a WPS depends on the project and industry requirements. A WPS is mandatory to ensure compliance and quality in many cases, especially those governed by codes and standards.

Final Thoughts:

A Welding Procedure Specification serves as a blueprint for consistently achieving high-quality welds. By incorporating detailed information about materials, processes, and parameters, WPS ensures welders can carry out their work precisely, resulting in reliable welded structures. Whether in constructing critical infrastructure, a well-defined WPS is the key to success in the welding industry.

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