Ultrasonic Thickness Gauges

Ultrasonic thickness gauges are non-destructive testing (NDT) instruments that measure wall thickness from one side, using ultrasonic pulses reflected from the back wall. They are used for metal thickness measurement on pipes, tanks, ship hulls and steel structures to assess corrosion, wear and remaining thickness — without cutting or dismantling anything.

This collection covers basic digital ultrasonic thickness gauges (Insize ISU-100D, ISU-200D, ISU-250C) for steel, aluminium, cast iron, plastics, glass and ceramics; through-coating models that ignore paint and measure only the metal (ISU-300D, ISU-800D, PCE-TG 300-P5EE); A-scan / B-scan instruments for thin or very thick workpieces (ISU-700D, ISU-710D, ISU-720D, ISU-810D, EMU-A100/B100); and the electromagnetic EMU-S340, which measures through up to 4 mm of rust. It also includes ultrasonic flaw detectors (UFD-T680, UFD-F720) and a glass thickness gauge for double glazing and laminated glass (5805-GT22). We are the official Insize representative in Greece and also stock PCE Instruments.

How to choose

• Painted surfaces — to measure the metal under paint or coating without grinding it off, choose a model with Echo-Echo (through-coating) mode.
• Range & thin material — standard models measure roughly 0.8–300 mm in steel; for sheet below 1 mm there are high-frequency probes (e.g. ISU-700D, 15 MHz).
• Small-diameter pipe — check the probe's minimum pipe size (e.g. Ø20 × 1.2 mm on the ISU-100D).
• A-scan / B-scan — the waveform confirms the reading is the true back-wall echo and not a flaw or a double reflection; useful for inspections and internally corroded material.
• Data logging — reading memory, alarm limits and USB output for inspection reports.

FAQ

How does an ultrasonic thickness gauge work? The probe sends an ultrasonic pulse into the material and times the echo returning from the back wall. With the speed of sound in that material known, the gauge calculates thickness — which is why calibrating on a known thickness or setting the correct material velocity matters.

Do I need couplant gel? Yes, conventional probes need a couplant between the probe and the surface. Gel, replacement probes and calibration blocks are in Ultrasonic Thickness Gauge Accessories.

Can it measure through paint? Only through-coating (Echo-Echo) models can. A standard ultrasonic gauge adds the paint thickness to the reading.

For more, read our guide to ultrasonic thickness gauges.