Understanding Code Compliant Ultrasonic Testing

Introduction

In today’s industrial setting, accurate inspection data is critical. The accuracy of this data depends on several factors, including the complexity of the equipment used. Ultrasonic equipment has significant capabilities to detect a variety of internal defects, but they are often very complex and highly dependent on the operator. This has effects on both individual inspections and the market as a whole. A Frost & Sullivan (June 2014) report stated that “the biggest growth driver for non-destructive testing (NDT) training services globally is a lack of qualified technicians.”

As the industry looks for alternative NDT methods to radiography, ultrasonic testing has gained popularity. The development of ultrasonic phased array images is important because they allow for a variety of structures to be inspected without radiation or taking equipment out of service. Large area B-scan and C-scan images have become commonplace. Codes are now being developed which allow phased array systems as an acceptable inspection technique for many procedures.

However, the complexity of these systems has led to several challenges for the market. The setup of phased array systems involves many complicated steps, each of which must be done correctly. Different inspections can require multiple costly probes to fully interrogate the target. However, the most challenging aspect of employing phased array systems is the dependence on the operator using the equipment. Training for these systems takes many weeks and requires in-depth knowledge of complicated UT focal laws and probe performance. This often limits repeatability and results in a high false call rate. If there is a time gap in using phased array, inspectors must be retrained. The most talented of phased array inspectors can generate accurate data. These inspectors are in high demand. This results in a high turnover rate as many inspectors jump from company to company leaving some many NDT service providers without adequate resources to run the UT equipment.

New Technology

Different from phased array UT, real-time ultrasound cameras for NDT usage are now available in the marketplace to address some of these issues. Some of the more advanced units available are essentially camcorders for ultrasound and have widespread applications. They can generate real-time C-scan imagery along with a quantitative A-scan reading, which is identical to a conventional flaw detector. Figure 1 shows our handheld system consisting of a handheld probe and touchscreen controller.