The Phased Array Ultrasonic Inner Inspection for the Butt Weld on the Head of High-Pressure Vessel

The layered high-pressure hydrogen vessels are widely used in hydrogen refueling stations. The head of the high-pressure vessel is made of austenitic stainless steel, and has thick walls, a pipe with a small diameter on the top and a butt-weld structure. It’s difficult to detect effectively, using conventional methods in the inspection of the butt weld on the head. To effectively detect the weld joint, a detecting method was investigated using ultrasonic phased array technique from the inner surface of the small-diameter pipe. By axial focusing and circumferential focusing, the ultrasonic field in austenitic stainless steel could satisfy the specific inspection requirement. Some ultrasonic field analysis and defect detection simulations were carried out with CIVA, for artificial defects such as side-drilled holes. Meanwhile, the test specimen and probe were designed and manufactured, and experiments were conducted. Furthermore, the feasibility and rationality of the detecting method and the simulation method were verified, and the detecting process parameters were determined.