TOFD

NDT course on TOFD

Computer Based Training Course on AUTOMATED ULTRASONIC TESTING
TOFD Testing
DETAILED CONTENTS: TOFD Testing (Time of Flight Diffraction)
(see Contents )



1. INTRODUCTION TO TECHNIQUES
1.1 Technique principle
- TOFD Signals
- Types of waves and signals produced
- Sizing a discontinuity
- Scan zones and dead zones
- Suitable scan materials
1.2 Advantages and disadvantages of TOFD
- Advantages of TOFD
- Disadvantages of TOFD
1.3 Data visualization
- A-scan presentation
- B-scan presentation


2. DETECTION OF DISCONTINUITIES
2.1 Defect inspection
- Scan types
- Non-parallel scan
- Parallel scan
- Combined scans
2.2 Defect characterisation
- Phase relationships between signals
- Types of discontinuity
2.3 Defect sizing
- Depth calculation
- Height calculation
- Measuring time of flight
- Calculation time of flight

3. LIMITS AND ADDITIONAL SCANS
3.1 Limitations of the technique
- Locating accuracy
- Calculation error in locating
- Spatial resolution
- Dead zones
- Calculating spatial resolution and dead zone
3.2 Additional scans
- Scans with different frequencies
- Scans with different emission angles
- Scans with offset distances

4. TOFD SYSTEM CALIBRATION
4.1 TOFD system structure
- Operation and characteristics
- Ultrasound probes
4.2 System calibration
- Geometric calibration
- Ultrasonic calibration
- Calibrating the acquisition system
- Other adjustments
4.3 Reference blocks
 
4.4 Image quality
- Basic requirements of TOFD image
- TOFD image anomalies

5. TOFD SIGNAL ANALYSIS
5.1 Introduction
  
5.2 Weld defects
- Examples of defects
5.3 Sizing defects
- Measuring depth and height
- Measuring length
- Examples of sizing
5.4 TOFD references
  

6. SELF-EVALUATION TESTS
Introduction to techniques
Detection of discontinuities
Limits and additional scans
TOFD system calibration
TOFD signal analysis