Knowledge

Tutorial Table of Contents

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 Gaging

1.1 Introduction
1.2 Benefits of Ultrasonic Gaging
1.3 History of Ultrasonic Thickness Gaging
1.4 Types of Equipment
1.5 Theory of Operation

2.0 Ultrasonic Transducers for Thickness Gaging

2.1 Transducers for Thickness Gaging
2.2 Transducer Construction
2.3 Beam Characteristics
2.4 Transducer Selection

3.0 Modes of Measurements

3.1 Single Element Transducers
3.2 DualElement Transducers
3.3 Advanced Techniques

4.0 Calibrating a Thickness Gage

4.1 What is gage calibration
4.2 Velocity and Zero Calibration
4.3 Calibration Certification

5.0 Gage Setup Considerations

5.1 Overview of Thickness Gage Setup
5.2 Typical Gage Adjustments

6.0 Factors Affecting Measurement

6.1 Material-related Factors
6.2 Equipment-related Factors
6.3 Operator-related Factors

7.0 Special Conditions

7.1 High Temperature Considerations
7.2 Measurements Through Coatings
7.3 On-line Measurements
7.4 Cable Length
7.5 Underwater Measurements

8.0 Typical Applications

8.1 Ultrasonic Gaging - Corrosion
8.2 Ultrasonic Gaging - Metals
8.3 Ultrasonic Gaging - Plastics
8.4 Ultrasonic Gaging - Other Materials

9.0 Appendices

9.1 Material Sound Velocities
9.2 Transducer Range Charts
9.3 Thickness Gaging Glossary