What is Certified Weld Inspection (CWI) Services?
Certified Weld Inspection (CWI) plays a critical role in ensuring that welded structures, components, and materials meet quality and safety standards set by various codes and specifications. CWI certification holders perform weld inspections for defects, ensuring compliance with welding codes and standards, conducting various tests (such as magnetic particle, radiographic testing, ultrasonic testing, etc. with additional certification in those disciplines), and providing detailed reports on the quality of the welds.
Weld technicians are certified in accordance with the respective training and certification standards developed by American Welding Society (AWS) and American Society of Mechanical Engineers (ASME). CWI technicians can accurately assess the configuration compliance, quality, and integrity of a wide range of materials and welding techniques of both ferrous and non-ferrous materials.
Weld Test Inspection Methods
Several methods are used for welding inspection to ensure the quality, integrity, and compliance of welds with industry standards. Here are some common welding inspection methods:
Visual Inspection (VT)
Welding visual inspection is the most basic and frequently used method. Inspectors visually examine welds for surface irregularities, discontinuities, cracks, porosity, incomplete penetration, or other defects. It involves using tools like magnifying glasses, mirrors, and cameras to assess the weld’s appearance.
Radiographic Testing (RT)
RT uses X-rays or gamma rays to create images of the internal structure of welds. It detects defects that might not be visible to the naked eye, such as internal cracks, inclusions, or incomplete fusion.
Ultrasonic Testing (UT)
UT uses high-frequency sound waves to detect internal defects in welds. It can identify discontinuities, cracks, and lack of fusion by analyzing the echoes produced when sound waves encounter inconsistencies in the material. Ultrasonic testing is a common method to inspect Complete Joint Penetration (CJP) welds. Contact Unitek to see how our services can help your company with CJP weld inspections.
Magnetic Particle Inspection (MPI)
This method is useful for detecting surface and near-surface flaws in ferromagnetic materials. A magnetic field is applied to the material, and finely divided magnetic particles are used to reveal discontinuities such as cracks or laps.
Liquid Penetrant Inspection (LPI)
LPI involves applying a liquid penetrant to the surface of a cleaned weld. The penetrant seeps into surface-breaking defects, and after a specified dwell time, excess penetrant is removed, and a developer is applied to draw out the penetrant, making defects visible.
Eddy Current Testing (ECT)
ECT is particularly useful for non-destructive testing of conductive materials. It uses electromagnetic induction to detect surface and near-surface flaws, variations in material thickness, and conductivity changes.
Infrared Thermography (IRT)
IRT uses infrared imaging to detect temperature variations that could indicate defects like lack of fusion or discontinuities. It requires specialized equipment and trained-certified personnel.
Advantages of Weld Inspection
Detecting problems with welds is of utmost importance to prevent them from escalating and addressing them promptly if detected. NTS Unitek’s team of weld inspectors diligently assesses the quality of welds at every stage of the fabrication process, including before, during, and after welding. This comprehensive approach ensures that any issues are identified and corrected as quickly as possible, guaranteeing the highest standards of weld integrity.
The NTS Unitek Benefit
Our team of highly qualified NDT inspectors can determine surface and subsurface discontinuities by carefully examining their nature, location, and extent. Look to Unitek to provide professional and reliable weld quality inspection support services that will help you validate your product conformity.
Please contact us to obtain further details regarding our CWI support services. The NTS Unitek team of experts is readily available to assist you with any inquiries you may have.
