The CTG series of Corrosion Thickness Gages are designed to accurately measure metal structures subject to corrosion. The gages offer a huge (100,00 Readings) data logger, Non Encoded B-Scan as standard features. The CTG- DL+ is equipped with COLOR A-Scan and the user can select rectification mode of his choice. A wide range of transducers are available and probe recognition is via pick list from a menu.

Salient Features

  • Simultaneous display of Thickness & COLOR A-Scan (in DL+)
  • Echo to Echo mode to ignore the paint or coating thickness
  • Q-Bar to confirm measurement stability
  • Ideal for high temperature thickness gaging applications
  • Vibration and COLOR change of A-Scan on alarm

Typical Applications

  • Boiler Tubes
  • Pressure Vessels
  • Storage Tanks
  • Ship Hulls
  • Containers
  • Oil Tanks
  • Pipes
  • Steam Lines
  • Compressor
  • Shafts
  • Bridge Pins
  • Bond Inspection


JMD NDT offers a wide variety of dual transducers from 0.5-10 MHz, high temperature duals and delay lines including pencil probes (12 MHz) for special applications. The DHT-537 high temperature dual (up to 950F intermittent use) is offered with optional Bell Housing and armored Dual Lemo to Microdoct 6’ cable. Spring Loaded Holder (for DK718 & DK718EE) is offered with dual v-notches for small diameter pipes and tubes.


Technical Specifications

Size: 5" (127mm) (L) x 3"(76.2 mm) (W) x 1.25" (31.75 mm) (H)
Weight: 8 OZ (0.23 kg)
Thickness Range: 0.020”– 20” (0.50 mm - 508 mm) in steel, depending on material, temperature & transducer selection
Material Velocity Calibration Range: 0.0200 - 0.7362 in/uS (0.508 - 18.699 mm/uS)
Operating Temperature: -4° F to 122° F (-20° C to 50° C)
Battery Life: 8 -14 hours (depends on operating conditions)
Battery Type: 2 "AA" Alkaline
Display: 170 X 220 pixels, high resolution TFT color display, sunlight readable
Language Support: English, French, Spanish, Italian, Czech, German, Chinese, Portuguese, Slovak, Finnish & Hungarian
Information Displays: Loss of signal (LOS), min, max, large reading while displaying min at the same time, velocity, zero, calibration, units, freeze, unfreeze, % battery life remaining, gain - low, std, high, echo to echo symbol
Resolution: 0.001" (0.01 mm), 0.01” (0.1 mm)
Bandwidth: 0.5-20 MHz (-3dB)
Units: English/Metric/Microseconds
Gain: CTG-DL: Low, Standard and High for varying test conditions CTG-DL+: 1 dB steps from 20-90 dB or Automatic Gain Control (AGC)
Differential Mode: Displays the difference from the actual thickness measurement in absolute or percentage of a user entered reference value
Alarms: Minimum/Maximum depth, vibrates, beeps and display flashes as well as keypad illumination & COLOR change of A-Scan
Illuminating Keypad: F1 = Red, F2 = Yellow and F3 = Green for easy, go/no-go testing
Backlight: Light Emitting Diode (LED), On/Off or Auto On based on valid readings or last key press
Shut Off: Auto, user programmable time out (1-31minutes), after no reading/key press or never shut off
Freeze Mode: Freezes display (ideal for high temperature applications)
Hold Mode: Holds display to retain last thickness reading
IP Rating: IP54
Warranty: 2-year Limited warranty on parts and labor if used under prescribed conditions
Data Logger: 100,000 readings in linear, 2D, 3D grid or boiler alphanumeric files, 20-character file name, file compare, grid review & export to excel via Data XL interface program, also compatible with Ultrapipe

Kit Contains

  • Ultrasonic Thickness Gage
  • DKS-537 5MHz, 0.375” diameter dual probe with 6' potted cable
  • Operational Manual
  • NIST traceable calibration certificate
  • Couplant
  • Transport Case
  • Data XL interface program & Protective Pouch

Optional Items

  • Step Wedges
  • Couplant
  • EZ-Scan 4 Scanner