Measurement and Evaluation of Metal-to-Metal Seals Sealability by Ultrasonic Phased Array

Abstract

The magnitude and distribution of contact stress on the metal-to-metal seal interface of premium connection has been confirmed as a direct factor of the sealing integrity. In this study, the method of evaluating sealability by measuring contact stress on metal-to-metal seals with the ultrasonic phased array is investigated. A loading system and ultrasonic phased array measurement system of cone-cone contact samples were created. The recommended detection method is focusing -deflection, and the time compensation method is suggested to extract the reflected wave peak of the sealing surface. The experiments show that the reflected wave peak declines with the rise of the axial load, with the big end showing the most noticeable reduction. The shift in the reflected wave peak also reflects the axial movement of the contact interface. The contact stress is calculated according to the reflection coefficient and compared with the simulation results. The distribution trend of contact stress is consistent. The sealing index measurement error is less than 15%, and the measurement error is decreased with the decrease of the sealing surface angle. Then, the nephogram of contact stress distribution on the sealing surface is formed to visualize the contact stress, which takes on great significance in engineering.

Keywords

• premium connection
• metal-to-metal seal
• contact stress
• sealing index
• ultrasonic phased array
• focusing-deflection