The use of ultrasonic thickness gauges can provide many advantages when a mill operator has to verify wall thickness of an extruded pipe or tube. In the mill, nondestructive wall thickness measurements of the pipe can be made to detect out-of-tolerance conditions. Concentricity of an extruded pipe can be monitored on a continuous and automatic basis with no need to cut the pipe or to shut down the manufacturing process. Similarly, when a machinist needs to accurately measure the thin wall of a tube, ultrasonics permits nondestructive thickness measurements along the total length.

Equipment: For manual thickness measurements, the Model 35DL Gauge provides instant digital readings of most metal pipes and tubes to a calibrated accuracy of ±0.001 inch (±0.01mm). This model used with an M112 contact transducer is capable of measuring most metal walls ranging from 0.020 to 1 inch (0.50 to 25.0mm). The Model 35 can also be used in situations where data logging is not required.
If the diameter of a tube is less than 0.125 inch (3mm), Panametrics recommends the Model 35DL and an immersion transducer. The Model RBS-1 Bubbler System is a helpful tool in making ultrasonic thickness measurements that utilize immersion transducers. The 35DL can be used with delay line transducers to make thickness measurements to a calibrated accuracy of ±0.0001 inch or ±0.00lmm.
For continuous on-line thickness measurements of metal pipes, the Model 25MX PLUS is capable of making measurements at up to eight points around the circumference. Immersion transducers can be used with a supply of clean water to couple the ultrasound into the exposed surface of the pipe. If necessary, a rust inhibitor or hot-air blower can prevent rust contamination. Selection of immersion transducers depends on pipe diameter and wall thickness.
Wall thickness measurements on metal pipes or tubes that are badly corroded on either the inside or the outside surface should, as a rule, be made with the Panametrics-NDT Model 37DL PLUS, or the MG2 series.

Products used for this application

35 Series
General purpose, lightweight Panametrics-NDT gauges feature optional live Waveform and Adjust Mode. 35DL and 35DL-HP have alphanumeric data logger.

MG2 Series
Pocket-sized, easy to use Panametrics-NDT corrosion gauges offer many measurement features such as B-pscan and optional A-scan. MG2-XT and MG2-DL offer Thru-Coat and Echo-to-Echo options to measure both coating and thickness.

37DL PLUS
Advanced Panametrics-NDT corrosion gauge with large A-scan display and sophisticated alphanumeric data logger. Features include Thru-Coat, Echo-to-Echo, B-scan acquisition, Emat, and optional Oxide/Scale measurement.

25MX PLUS
This Panametrics-NDT gauge makes multipoint and single thickness measurements. Up to eight transducers can be connected to the optional MX-8 Multiplexer.