Tandem Wedge for In-service Inspection of Cladding to Detect Vertical Flaws in Pressure Vessel Components

Cladding is a process of weld overlay to protect the base metal from corrosive fluids and fumes ensuring its longevity. Cladding aid to obtain a suitable material at a reasonable cost, consisting of low-cost base material with excellent mechanical properties (such as carbon steel), and another material resistant to corrosion, abrasion or oxidation (such as stainless steel, Inconel) To ensure bonding between the clad and parent material, Non-Destructive Examination (NDE) Techniques are used. Among the various NDE techniques, conventional ultrasonic testing (UT) serves as a reliable method during the manufacturing stage.However, during operation there is a risk of defects propagating in the clad-parent material interface, thereby reducing the service life of the product. The conventional UT methods are not effective in detecting vertical flaws in the interface region of cladding and base metal. To effectively detect vertical flaws, a Tandem Wedge was designed for generating Longitudinal acoustic wave (L-wave) with 45° refracted angle in steel. This paper details about the design and development of the Tandem wedge to detect vertical flaws in cladding.