The four typical NDE methods for defense pressure vessels are: Radiographic Testing (X-ray or gamma) to find internal weld flaws and create a permanent record; Ultrasonic Testing to detect internal cracks or lack of fusion and verify thickness with portable, fast equipment; Liquid Penetrant Testing for surface-breaking defects on nonporous materials; and Magnetic Particle Testing for quick detection of surface and near-surface flaws in ferromagnetic welds. Teams often combine methods to balance defect coverage, field portability, safety, cost, and ASME-compliant documentation.
The ability to evaluate a pressure vessel’s integrity is important, but particularly so in the defense industry, where mission success is always vital. However, it’s not always obvious which nondestructive examination (NDE) method is best.
Whether it’s to cut costs, ensure compliance or enhance portability, choosing the right NDE method is critical.
Four Key NDE Methods
There are four key defense pressure vessel NDE methods that can be applied to pressure vessels. Each method has its own advantages and uses, which is why multiple methods may be necessary for a comprehensive examination.
Radiographic Testing (RT)
Using X-rays and gamma rays, RT allows for internal analysis of a pressure vessel’s condition. This method can detect internal weld flaws in a pressure vessel, such as porosity and inclusions, making it useful for verifying the integrity of critical butt welds.
RT also creates a permanent film record of the inspection, making it easy to keep a paper trail that can be reviewed in the future. However, this method can pose a radiation risk to operators, so the proper safety precautions are vital.
Ultrasonic Testing (UT)
UT uses high-frequency soundwaves to detect internal planar flaws. In pressure vessels, these flaws could be cracks or a lack of fusion. This versatile defense vessel weld inspection method can also be used to measure material thickness, allowing operators to determine the integrity of a pressure vessel.
Since UT equipment is portable and can deliver fast results, it can be quickly carried out in the field, making it particularly useful in the defense industry. UT is commonly used to evaluate full penetration welds.
Liquid Penetrant Testing (PT)
PT can reveal a pressure vessel’s external defects, such as cracks, seams or porosity. The vessel is sprayed with a liquid penetrant, which seeps into any defects, making them easy to identify. This cost-effective and simple method can be applied to any nonporous material, meaning that it can be used on most pressure vessels and weld types.
Magnetic Particle Testing (MT)
Another method of testing a pressure vessel’s external condition is MT, which requires the application of fine ferromagnetic particles to the pressure vessel’s exterior. Once magnetized, these particles are attracted to disruptions in the magnetic field caused by imperfections in the vessel’s surface and shallow subsurface.
MT is fast and particularly effective at identifying cracks in fillet welds and lamellar tears in T-joints.
Get Audit-Proof NDE Documentation
Choosing the best pressure vessel NDE method is only the first step toward mission success and compliance. Defense contracts often require clear documentation that your examinations meet the American Society of Mechanical Engineers (ASME) standards. Failure to provide documentation of your ASME vessel inspection methods can delay the project and risk the mission’s success.
A complete documentation package should include:
Inspection reports
Technician certifications
Material traceability records
A Defense Partner for End-to-End Compliance
At BEPeterson, our knowledge of pressure vessel NDE requirements, in-house NDE capabilities and rigorous quality assurance program make us the ideal partner for your pressure vessel needs. We custom-make each pressure vessel to ASME standards, ensuring it meets your specific needs. With over 90 years of experience, we’ve been trusted to deliver reliable pressure vessels on many defense projects.
To find out how we can design and manufacture your custom pressure vessel, request a quote today.
