Weld Testing & Inspection

Scope

Weld testing and inspection covers non-destructive, mechanical, and metallurgical evaluation of welded joints to verify quality and qualify procedures and welders against the applicable code or standard. The specific methods are selected based on the code, the joint, and the purpose of the evaluation.

The methods within the scope include:

• Non-destructive testing (NDT) – visual inspection (VT), radiographic testing (RT), ultrasonic testing (UT including phased array), magnetic particle testing (MT), and liquid penetrant testing (PT) to detect surface and internal weld defects
• Mechanical (destructive) testing – tensile tests (transverse and all-weld-metal), guided and free bend tests (root, face, side), impact toughness (Charpy V-notch), and hardness surveys across the weld and heat-affected zone
• Metallurgical examination – macro-etch examination of cross-sections for fusion, penetration, and defects, and microstructural examination of the weld and heat-affected zone
• Procedure and welder qualification – testing to qualify welding procedure specifications (WPS/PQR) and to qualify/certify welders per the governing code
• Governing codes and standards – AWS D1.1 (structural steel), ASME BPVC Section IX (welding qualification), ISO 15614 (welding procedure qualification), and related code requirements
• Applicable joints and materials – welds in carbon and alloy steels, stainless steels, aluminum, nickel alloys, and other weldable metals

Applications

• Welding procedure qualification (WPS/PQR) – performing the testing required to qualify a welding procedure, demonstrating it produces sound welds with the required properties
• Welder performance qualification – testing welds made by individual welders to qualify and certify them per AWS, ASME, or ISO requirements
• Production weld verification – NDT and, where required, destructive testing of production welds to confirm they meet acceptance criteria
• Structural steel fabrication – weld inspection and testing for buildings, bridges, and structures per AWS D1.1
• Pressure equipment and piping – weld testing for boilers, pressure vessels, and piping per ASME code requirements, where weld integrity is critical to safety
• Pipeline welding – verification of pipeline girth and seam welds against the applicable pipeline welding code
• Weld failure investigation – examining failed welds to determine whether weld defects, improper procedure, or service conditions caused the failure
• Fabrication quality control – ongoing weld quality verification in manufacturing and fabrication operations

Benefits

• Detects defects that compromise weld integrity – NDT and metallurgical examination find porosity, cracks, lack of fusion, and incomplete penetration that can cause weld failure, including defects invisible on the surface
• Verifies the weld has the required properties – mechanical testing confirms the weld and heat-affected zone meet the strength, ductility, and toughness requirements, not just that the weld looks acceptable
• Qualifies procedures and welders – the testing provides the evidence needed to qualify welding procedures and certify welders, a code requirement in most fabrication
• Combines complementary methods – using NDT, mechanical, and metallurgical methods together evaluates the weld for both defects and properties, giving a complete assessment
• Supports code conformance and safety – weld testing demonstrates that welds meet AWS, ASME, or ISO requirements, which is essential for structural, pressure, and safety-critical applications
• Identifies root cause in failures – metallurgical and fractographic examination of failed welds reveals why the weld failed, supporting corrective action