One of the most crucial steps before assigning a welder to production or fabrication welding is the Welder Qualification Test (WQT), which evaluates the welder’s ability to create sound, defect-free welds as per the defined welding procedure specifications (WPS). A successful completion of the Welder Qualification Test is essential for ensuring that the welder is capable of performing at the highest standards of quality and safety.

What is the Welder Qualification Test (WQT)?

The Welder Qualification Test (WQT), also known as Welder Performance Qualification (WPQ) or Performance Qualification, is a test to determine the skill level of a welder. It ensures that the welder can create a strong, durable, and defect-free weld that meets industry standards and safety requirements. This test is essential before a welder can be assigned to production welding or fabrication work, and it serves as a guarantee to employers and clients that the welder is skilled in producing sound welds in various applications.

How is the Welder Qualification Test Conducted?

The Welder Qualification Test is conducted in several key steps to evaluate the welder’s skills and ensure compliance with relevant standards, such as ASME Section IX or AWS D1.1:

1. Preparation of Test Coupon: A test coupon, or test piece, is prepared according to the requirements of the Welding Procedure Specification (WPS). This coupon represents the material, joint configuration, and welding process that the welder will be using in real-world conditions.
2. Welding Process: The welder performs the welding procedure on the test coupon as per the WPS. It is crucial that the welder adheres to the exact parameters set out in the WPS, including welding current, voltage, filler material, and welding technique.
3. Initial Visual Inspection: After completing the root run, a visual inspection is carried out to check for any visible defects such as lack of fusion, lack of penetration, or surface imperfections. Depending on the WPS, additional nondestructive tests (NDT) such as Liquid Penetrant Testing (LPT) or Dye Penetrant Testing (DPT) may be performed.
4. Further Welding and Inspection: If the root run passes the initial inspection, the welder continues with the fill and final passes of the weld. After completing the entire weld, another visual inspection is conducted, followed by further nondestructive testing, which may include Magnetic Particle Inspection (MPI), Ultrasonic Testing (UT), or Radiographic Testing (RT) based on the WPS requirements.
5. Final Testing and Evaluation: Once the test coupon is completed and passes the visual and NDT inspections, it is subjected to final mechanical testing. These tests may include tensile tests, bend tests, or impact tests to assess the strength and durability of the weld. The test coupon’s integrity is thoroughly evaluated to ensure it meets the required specifications.
6. Certification: After passing the performance qualification test and the final evaluations, a welder is issued a certificate along with an identity card. This confirms that the welder is qualified for specific welding tasks and can be employed for production or fabrication welding.

Key Factors to Consider in the Welder Qualification Test

Several factors must be considered when conducting the Welder Qualification Test to ensure the welder’s skills align with the welding requirements:

• Welding Procedure Specification (WPS): The WPS is a critical document that outlines all the parameters and guidelines for the welding process. This document ensures that the welding process is carried out correctly and consistently.
• Welding Process: Each welding process requires a separate qualification. For instance, a welder who is qualified in Shielded Metal Arc Welding (SMAW) may not be automatically qualified for MIG/MAG welding. The welder must pass a separate test for each process.
• Size of the Test Coupon: The size of the test coupon is important as it must be large enough to allow for the required testing (e.g., radiographic or mechanical tests). Additionally, the thickness of the weld deposit plays a significant role in determining the welder’s qualification for different thickness ranges.
• Position of the Test Coupon: The position in which the test coupon is welded also affects the welder’s qualification. Welder positions can be flat, horizontal, vertical, or overhead, and each position presents different challenges. If a welder qualifies in a specific position, they are only qualified to perform welding in that position or similar positions, unless specified otherwise in the WPS.
• Filler Material/Electrode: The type of filler material or electrode used during the welding process must also comply with the requirements specified in the WPS. The correct choice of filler material is essential for producing strong, reliable welds.

Thickness and Diameter Limitations for Welder Qualification

The thickness of the weld metal deposited during the qualification test is a critical factor in determining the welder’s qualification. According to ASME Section IX, the following guidelines apply:

• Maximum Weldable Thickness: A welder is allowed to weld a maximum thickness of 2T, where T is the thickness of the weld metal deposited on the test coupon. This means that a welder is qualified to weld materials up to twice the thickness of their qualification test deposit.
• Qualification for Unlimited Thickness: If a welder deposits at least 13 mm (1/2 inch) of weld metal, with a minimum of three layers, they qualify for unlimited thickness, but the maximum thickness they are allowed to weld must still adhere to the WPS requirements.

For pipe welding, the diameter limits for groove welding are also critical, and these limits are outlined in Table QW 452.3 of ASME Section IX.

Position Qualification

A welder’s qualification also depends on the positions in which they are capable of welding. For example:

• A welder who qualifies in the 2G position (horizontal position) is qualified for both horizontal and flat welding.
• A welder who qualifies in the 6G position is considered to be qualified for all positions, making the 6G test one of the most demanding and prestigious qualifications in the industry.

At DV Training Services Pte. Ltd., we offer comprehensive training and testing in all welding positions, including the challenging 6G position, ensuring that our welders are capable of handling all types of welding challenges.

Conclusion

The Welder Qualification Test (WQT) at DV Training Services Pte. Ltd. is a rigorous and essential process to ensure that welders are skilled, knowledgeable, and capable of producing high-quality, defect-free welds in various applications. Our training programs cover all aspects of the qualification process, from test coupon preparation to final testing and certification. By choosing DV Training Services Pte. Ltd., you can be assured that your welders are trained to meet industry standards and are qualified to handle any welding task, no matter how complex or demanding.

Whether you are a company looking to certify your workforce or an individual seeking to enhance your welding skills, DV Training Services Pte. Ltd. is your trusted partner in achieving the highest welding standards.