Ultrasonic thickness gaging is a widely used nondestructive technique for measuring the thickness of a material from one side. Just about anything made out of metal, plastic, composite, ceramic, glass, fiberglass, or rubber can be measured. This tutorial provides a basic introduction to the theory and practice of ultrasonic thickness gaging, for both newcomers and more experienced users who would like a review. It covers basic ultrasonic theory, how ultrasonic gages work and how they are used, and discusses a number of specific gage applications. Additional reference information including a glossary can be found in the Appendix.1.0 Introduction to Ultrasonic Thickness Gaging1.1Introduction1.2Benefits of Ultrasonic Gaging1.3History of Ultrasonic Thickness Gaging1.4Types of Equipment1.5Theory of Operation2.0 Ultrasonic Transducers for Thickness Gaging2.1Transducers for Thickness Gaging2.2Transducer Construction2.3Beam Characteristics2.4Transducer Selection3.0 Modes of Measurements3.1Single Element Transducers3.2DualElement Transducers3.3Advanced Techniques4.0 Calibrating a Thickness Gage4.1What is gage calibration4.2Velocity and Zero Calibration4.3Calibration Certification5.0 Gage Setup Considerations5.1Overview of Thickness Gage Setup5.2Typical Thickness Gage Adjustments6.0 Factors Affecting Measurement6.1Material-related Factors6.2Equipment-related Factors6.3Operator-related Factors7.0 Special Conditions7.1High Temperature Considerations7.2Measurements Through Coatings7.3On-line Measurements7.4Cable Length7.5Underwater Measurements8.0 Typical Applications8.1Ultrasonic Gaging - Corrosion8.2Ultrasonic Gaging - Metals8.3Ultrasonic Gaging - Plastics8.4Ultrasonic Gaging - Other Materials9.0 Appendices9.1Material Sound Velocities9.2Transducer Range Charts9.3Thickness Gaging Glossary