Welder Qualification and Welding Procedure Qualification
Welder qualification tests are intended to determine the ability of welders and welding operators to make sound welds, and are used in welder certification. Organizations qualify welders or welding operators for each welding process used in production welding.
Weld testing involves performing tests on a weld to confirm that results meet the requirements specified in a procedure. The results of weld testing are used to qualify a welder to a stated procedure, often as part of pre-employment screening or for welder certification, by ensuring that the skills of the welder meet code and/or the company’s standards. In the United States there are a number of organizations that have certified welding programs. Some of the largest organizations include the American Welding Society (AWS) typically dealing with structural codes for buildings and bridges and the American Society of Mechanical Engineers (ASME) dealing with boiler and pressure vessel codes.
Laboratory Testing Inc. offers independent, third-party weld testing and welder qualification services for certification and welding procedure qualification. All of the required weld testing and inspections are provided to verify that the weld procedure was followed properly, correct filler material was used and the weld joint lines up accurately. LTI’s full scope of capabilities include the following:
- Welder Qualification Testing for performance qualification and welder certification to ASME, ANSI, AWS and API code and Military standards
- Preparation of Welding Procedure Qualification as per client or project requirements
- Documentation of the Welding Procedure Qualification in a Certified Test Report as per ASME, ANSI, AWS and API code and Military standards
- Coupon Testing as per Welding Procedure Qualification which includes visual examination, mechanical testing, metallographic examination and nondestructive testing
Laboratory Testing is a full-service weld test and welder qualification provider with complete in-house resources to turn your order around quickly and reliably. Our staff includes Level II Inspectors in Visual Examination. The lab also has a full-service Machine Shop equipped with band saws and CNC milling, turning and grinding centers to handle any size weld coupon. The Machine Shop and testing labs run first and second shifts to process the orders under tight deadlines.
Weld Test and Welder Qualification Processes
A few types of weld testing are performed in LTI’s Metallography Laboratory – macroetch exam, hardness testing and ferite examination. The macroetch exam is typically performed on a finely ground cross-section taken transverse to the weld axis that has been etched with a chemical reagent to distinguish the weld, heat affected zone (HAZ), and base metal areas. Examination for characteristics such as weld size, fusion, penetration, profile, and weld discontinuities is performed at magnifications anywhere between 1X and 50X. Various AWS, ASME, military, and customer specifications call for macroetch examination.
The weld test for hardness evaluates the strength of the weld and is performed on a ground and etched sample, similar to the macroetch specimen. The most commonly employed scale for weld testing at LTI is the 10 Kg Vickers. This generally involves checking the hardness in all three zones, including weld , HAZ and base according to a pattern prescribed by the referenced specification. Hardness testing of welds is an extremely common practice and requirement in the oil and gas industry. One of the most commonly encountered specifications being NACE MR0175 / ISO 15156, and or a company-specific derivation.
Ferrite examination by the point count method and feritscope are performed to determine the amount of ferrite present in the weld metal, HAZ and/or base metal. The point count test is performed on a polished and etched cross-section of the sample per the point count method described in ASTM E562 or a company-specific derivation. The point count test is typically applied only to welds that involve the duplex stainless steels. Ferrite examination by feritscope is a nondestructive test performed with a contact probe that calculates ferrite via electro-magnetic response. This test is typically applied to welds that involve the austenitic steels.
LTI’s Chemistry Lab analyzes weld overlays as well as raw materials using various methods that include dilution analysis for overlays and Inductively-Coupled Plasma Spectroscopy (ICP) and Atomic Emission Spectroscopy (AES) for raw materials. The weld dilution test is used in weld qualification and involves dilution of the weld metal by the base metal following procedures to perform the test at specific distances from the base metal. The weld metal analysis is usually performed to AWS or ASME Part C specifications.
Both mechanical and nondestructive testing methods provide necessary information for welder qualification and procedure qualification. LTI offers Visual, Liquid Penetrant, Magnetic Particle and Radiographic Inspection for nondestructive evaluation. These tests are usually done in conjunction with applicable mechanical testing such as tensile, bending or impact testing according to the same specifications.
Weld Testing Methods for Welder Qualification
- Vickers Hardness Testing
- Ferrite Exam –Point Count and Feritscope
- Dilution Analysis
- Inductively-Coupled Plasma Spectroscopy (ICP)
- Atomic Emission Spectroscopy (AES)
- Tensile Testing
- Guided-Bend Tests – Plunger Type and Wrap Around Bends
- Charpy Impact Testing
- Drop Weight Testing
- Nick Break Tests
- Push Out Tests
- Peel Tests
- Section Tests
- Hardness Testing
- Fracture Toughness
- Visual Examination
- X-ray/Radiographic Inspection
- Magnetic Particle Inspection
- Liquid Penetrant Testing