Common Ultrasonic Thickness Measurement Errors Malaysia

Common Ultrasonic Thickness Measurement Errors Malaysia

Complete Troubleshooting Guide for Incorrect Readings, No Readings and Unstable Ultrasonic Thickness Measurements

Ultrasonic thickness measurement errors in Malaysia are common concerns among factory maintenance technicians, engineering contractors, quality control personnel and industrial inspection teams.

An ultrasonic thickness gauge is used to measure the thickness of compatible materials without cutting or damaging the inspected component.

It is commonly applied to steel pipes, storage tanks, metal plates, industrial equipment and suitable marine components.

However, inaccurate or unstable readings may occur when the instrument is incorrectly configured or the inspection conditions are unsuitable.

Typical problems include:

Incorrect thickness readings

No thickness reading

Unstable or fluctuating readings

Incorrect material sound velocity

Insufficient ultrasonic coupling gel

Damaged or unsuitable probes

Rough or corroded surfaces

Measurement difficulties on curved components

Incorrect reference block verification

The Benetech GT-1202 Ultrasonic Thickness Gauge is a portable instrument that may be considered for compatible material thickness measurement applications.

In this guide, MTM Precision Sdn Bhd explains the most common ultrasonic thickness measurement problems, possible causes and practical troubleshooting methods.

Important: The information below describes general ultrasonic thickness measurement principles. Model-specific settings, operating limits and troubleshooting procedures for the GT-1202 should be confirmed using the manufacturer's official manual.

Why Do Ultrasonic Thickness Measurement Errors Occur?

An ultrasonic thickness gauge measures the travel time of ultrasonic sound waves passing through a material.

The instrument calculates thickness using the selected material sound velocity.

For conventional pulse-echo measurement:

Thickness = Sound Velocity × Travel Time ÷ 2

Reliable measurement depends on several factors:

Correct material sound velocity

Suitable ultrasonic probe

Proper probe contact

Adequate ultrasonic couplant

Compatible material and geometry

Appropriate surface preparation

Correct instrument settings

Reliable instrument verification

If any of these conditions are unsuitable, the displayed reading may be incorrect or unstable.

For example, a technician measuring a steel pipe may obtain an unexpected reading if the instrument is configured for another material.

Similarly, a heavily corroded surface may prevent reliable ultrasonic transmission.

Error 1 - Ultrasonic Thickness Gauge Shows Incorrect Thickness

One of the most common problems is a displayed thickness that differs from the expected value.

Possible Causes

Incorrect material sound velocity

Incorrect instrument adjustment

Unsuitable probe

Poor ultrasonic coupling

Incorrect echo interpretation

Measurement on an unsuitable surface

Incorrect reference thickness information

Recommended Troubleshooting

Step 1: Confirm the material being measured.

Step 2: Check the selected sound velocity.

Step 3: Verify the instrument using a suitable reference block.

Step 4: Check the probe condition and connection.

Step 5: Improve surface preparation and coupling.

Step 6: Repeat the measurement.

If the instrument continues to produce unacceptable errors on a suitable reference block, further calibration or service assessment may be required.

Error 2 - Ultrasonic Thickness Gauge Shows No Reading

A thickness gauge may fail to display a valid thickness value.

This can occur when the instrument cannot obtain a reliable ultrasonic signal.

Possible Causes

Insufficient ultrasonic couplant

Poor probe contact

Damaged probe cable

Incorrect probe connection

Unsuitable material

Excessive surface roughness

Severe corrosion

Thickness outside the instrument's supported range

Recommended Troubleshooting

First, check whether the instrument operates correctly on a suitable reference block.

If it measures the reference block correctly but fails on the inspected component, the problem may relate to the material, geometry or surface condition.

If it cannot measure the reference block, check the probe, cable, connector and instrument configuration.

Do not assume that every no-reading condition indicates an instrument defect.

Error 3 - Thickness Readings Keep Changing

Unstable ultrasonic thickness readings may occur when the displayed value changes repeatedly at the same inspection point.

Possible Causes

Probe movement

Uneven surface

Inconsistent probe pressure

Insufficient couplant

Poor ultrasonic transmission

Probe wear

Material irregularities

Unstable echo detection

Recommended Troubleshooting

Clean the inspection surface.

Apply suitable ultrasonic couplant.

Maintain stable probe contact.

Repeat the measurement using the appropriate technique.

If readings remain unstable, verify the instrument on a reference block.

For highly irregular or corroded surfaces, a specialised probe or inspection method may be necessary.

Error 4 - Incorrect Material Sound Velocity Setting

Sound velocity error is an important cause of incorrect ultrasonic thickness measurement.

Different materials transmit ultrasonic sound waves at different velocities.

For example:

MaterialApproximate Longitudinal Sound VelocityCarbon Steel5,900 m/sStainless Steel5,700-5,900 m/sAluminium6,300 m/sCopper4,700 m/sBrass4,400 m/s

Note: These are approximate reference values. Actual velocities vary with material composition, structure and conditions.

Example of Sound Velocity Error

Suppose a material has an actual longitudinal sound velocity of 5,900 m/s.

If the thickness gauge is incorrectly set to 6,300 m/s, the displayed thickness will be approximately 6.8% higher than the correct value, assuming the same measured travel time.

For a true thickness of 10.00 mm, the indicated thickness would be approximately:

10.00 × 6,300 / 5,900 = 10.68 mm

This example demonstrates why correct sound velocity settings are important.

Recommended Troubleshooting

Confirm the material.

Use an appropriate reference sample where possible.

Verify the sound velocity setting before beginning the inspection.

Do not assume that one velocity setting is suitable for every metal.

Error 5 - Insufficient Ultrasonic Coupling Gel

Ultrasonic coupling gel helps transmit sound energy between the probe and the test material.

Air gaps between the probe and material can interfere with ultrasonic transmission.

Possible Symptoms

No reading

Unstable reading

Intermittent measurement

Difficulty obtaining consistent results

Recommended Troubleshooting

Apply a suitable amount of ultrasonic couplant.

Ensure that the probe contact surface is clean.

Position the probe correctly.

Repeat the measurement.

Important: Using excessive couplant does not automatically improve measurement accuracy. The correct technique depends on the probe and application.

Error 6 - Damaged or Unsuitable Ultrasonic Probe

The ultrasonic probe is a critical component of the thickness measurement system.

Probe damage or incompatibility may affect measurement performance.

Possible Problems

Worn probe contact surface

Damaged cable

Loose connector

Incorrect probe type

Unsuitable probe frequency

Inappropriate probe geometry

Recommended Troubleshooting

Inspect the probe and cable for visible damage.

Check the connector.

Confirm that the probe is compatible with the instrument.

Verify the instrument using a suitable reference block.

If a probe is defective, replacement or professional service assessment may be necessary.

Important: Do not assume that all ultrasonic probes are interchangeable with the Benetech GT-1202.

Error 7 - Rough or Corroded Metal Surface

Rough surfaces may prevent stable probe contact.

Corrosion, rust, scale and irregular metal surfaces may interfere with ultrasonic transmission.

Common Applications

Corroded steel pipes

Industrial storage tanks

Marine steel plates

Factory equipment

Metal components exposed to moisture

Recommended Troubleshooting

Remove loose rust or dirt where appropriate.

Prepare a suitable contact area.

Avoid unnecessary removal of sound base metal.

Apply suitable couplant.

Repeat the measurement.

If the surface is severely pitted or irregular, conventional point thickness measurement may not be sufficient.

A specialised corrosion inspection technique may be required.

Error 8 - Incorrect Readings on Curved Pipes

Measuring curved components can be more difficult than measuring flat metal plates.

Small-diameter pipes may provide limited probe contact area.

Possible Causes

Probe does not sit correctly

Poor coupling

Unsuitable probe size

Incorrect probe orientation

Curvature-related measurement limitations

Recommended Troubleshooting

Confirm the probe's suitability for the pipe diameter.

Use the appropriate positioning technique.

Maintain stable contact.

Follow the manufacturer's instructions.

For difficult pipe geometries, consult a qualified inspection specialist.

Error 9 - Measurement Through Paint or Protective Coatings

Protective coatings may affect conventional ultrasonic thickness measurement.

A standard pulse-echo reading may include effects associated with the coating and measurement technique.

Possible Problems

Unexpectedly high readings

Inconsistent results

Difficulty obtaining a valid echo

Incorrect interpretation of metal thickness

Recommended Troubleshooting

Confirm whether the instrument supports the required coating measurement method.

Follow the applicable inspection procedure.

Where necessary and permitted, prepare an appropriate measurement area.

Important: Do not assume that the Benetech GT-1202 has automatic coating compensation or echo-to-echo measurement capability without official manufacturer confirmation.

Error 10 - Incorrect Reference Block Verification

A reference block is used to check instrument measurement performance.

Verification problems may occur when the reference sample is unsuitable.

Possible Causes

Unknown reference thickness

Incorrect material sound velocity

Damaged reference surface

Poor probe contact

Inappropriate reference thickness

Incorrect verification procedure

Recommended Troubleshooting

Use a suitable reference block with known thickness.

Confirm the reference material.

Apply couplant where required.

Follow the manufacturer's verification procedure.

Record the displayed reading and compare it with the reference value.

For formal calibration, use appropriate traceable reference standards and procedures.

Error 11 - Temperature-Related Measurement Problems

Temperature can affect ultrasonic thickness measurement.

Potential influences include changes in material sound velocity, probe performance and coupling conditions.

Common Situations

Hot industrial piping

Process equipment

Heated metal components

Outdoor inspection under strong sunlight

Temperature-sensitive materials

Recommended Troubleshooting

Confirm the instrument and probe operating temperature limits.

Use an appropriate probe and procedure for the measurement conditions.

Allow suitable temperature stabilisation where necessary.

Do not use a standard probe on a hot surface unless its temperature rating permits the application.

Error 12 - Measurement Errors Caused by Material Structure

Some materials may be difficult to measure using conventional ultrasonic thickness gauges.

Examples may include certain cast metals, coarse-grained materials and components with significant internal attenuation.

Possible Symptoms

Weak ultrasonic signal

No reading

Inconsistent thickness values

Difficulty measuring thick components

Recommended Troubleshooting

Confirm material compatibility.

Consider whether a different probe frequency or specialised ultrasonic technique is required.

Consult a qualified inspection specialist when the material is difficult to measure.

Quick Ultrasonic Thickness Gauge Troubleshooting Table

ProblemPossible CauseRecommended ActionIncorrect thicknessWrong sound velocityVerify material settingNo readingPoor couplingCheck couplant and contactUnstable readingProbe movementStabilise probeHigh readingVelocity or echo errorVerify on reference blockLow readingWall loss or measurement errorRepeat and investigateNo reading on corroded steelRough surface or signal lossPrepare surface or use suitable methodDifferent pipe readingsCurvature or thickness variationCheck probe suitabilityIncorrect reading through paintCoating interferenceConfirm measurement methodReference block errorIncorrect settings or probe issueRecheck verification procedureHot surface measurement problemTemperature limitationConfirm probe temperature rating

Step-by-Step Troubleshooting Checklist for Benetech GT-1202

If the Benetech GT-1202 produces unexpected readings, follow this general checklist.

Step 1 - Check the Instrument

Confirm that the instrument powers on and operates normally.

Step 2 - Inspect the Probe

Check the probe surface, cable and connector.

Step 3 - Confirm Material Compatibility

Verify that the inspected material is suitable for ultrasonic thickness measurement.

Step 4 - Check the Sound Velocity

Confirm the selected material sound velocity.

Step 5 - Verify on a Reference Block

Check the instrument using a suitable known-thickness sample.

Step 6 - Prepare the Surface

Remove loose contamination and ensure appropriate probe contact.

Step 7 - Apply Couplant

Use suitable ultrasonic coupling gel.

Step 8 - Repeat the Measurement

Obtain multiple readings according to the inspection procedure.

Step 9 - Compare the Results

Compare the readings with reliable reference information.

Step 10 - Seek Technical Assistance

If the problem remains unresolved, contact the supplier or a suitable service provider.

For critical inspections, suspend reliance on questionable readings until the measurement system has been properly assessed.

When Should an Ultrasonic Thickness Gauge Be Sent for Calibration or Repair?

A thickness gauge may require further assessment when:

It repeatedly fails reference block verification.

The readings are unstable under suitable test conditions.

The probe or connector is damaged.

The instrument cannot operate normally.

The displayed thickness is consistently outside the required tolerance.

Calibration documentation is required for the intended application.

Calibration establishes instrument measurement performance.

Verification checks compliance with specified requirements.

Adjustment changes instrument settings or response.

Repair addresses damaged or malfunctioning components.

These activities are different and should not be confused.

How to Prevent Ultrasonic Thickness Measurement Errors

A good measurement procedure can reduce avoidable errors.

Recommended practices include:

Verify the instrument before use.

Use the correct material sound velocity.

Select a compatible probe.

Prepare the inspection surface properly.

Apply suitable ultrasonic couplant.

Maintain stable probe contact.

Follow the correct measurement procedure.

Record inspection locations consistently.

Repeat questionable measurements.

Maintain calibration and verification records.

For safety-critical equipment, qualified inspection personnel and appropriate engineering assessment may be required.

Applications Where Accurate Thickness Measurement Matters

Industrial Pipe Inspection

Reliable thickness measurements support monitoring of suitable metal piping systems.

Storage Tank Inspection

Thickness readings may help identify possible wall thinning at selected tank locations.

Factory Preventive Maintenance

Maintenance teams may use thickness data to monitor compatible industrial equipment.

Steel Fabrication

Thickness measurement may support material verification and quality control.

Marine Maintenance

Suitable ship components may require thickness monitoring as part of maintenance programmes.

Corrosion Monitoring

Repeated measurements may support evaluation of possible corrosion-related material loss.

Ultrasonic Thickness Gauge Troubleshooting Across Malaysia

Selangor and Kuala Lumpur

Industrial maintenance, engineering contractors, factory inspection and measuring instrument enquiries.

Johor

Manufacturing, steel fabrication, marine-related maintenance and industrial inspection.

Penang

Precision manufacturing, quality control and engineering facilities.

Melaka and Negeri Sembilan

Factory maintenance, industrial equipment inspection and mechanical engineering.

Perak, Pahang, Kedah, Kelantan, Terengganu and Perlis

Industrial maintenance and suitable metal thickness measurement applications.

Sabah and Sarawak

Industrial facilities, marine maintenance and suitable pipeline inspection applications.

MTM Precision supports industrial measuring instrument enquiries from customers throughout Malaysia.

Frequently Asked Questions

Why is my ultrasonic thickness gauge showing the wrong thickness?

Possible causes include incorrect sound velocity, unsuitable probe configuration, poor coupling, surface conditions or instrument errors.

Why does my thickness gauge show no reading?

The instrument may not obtain a reliable ultrasonic signal because of poor contact, insufficient couplant, material limitations or probe problems.

Why do ultrasonic thickness readings keep changing?

Unstable readings may result from probe movement, rough surfaces, poor coupling or inconsistent echo detection.

Can incorrect sound velocity cause thickness errors?

Yes. The instrument calculates thickness using sound velocity, so an incorrect setting can produce systematic measurement errors.

Can ultrasonic thickness gauges measure through paint?

This depends on the instrument's measurement method and coating conditions. Coating compensation should not be assumed without manufacturer confirmation.

Can a damaged probe cause inaccurate readings?

Yes. Probe wear, cable damage or connector problems may affect measurement performance.

Can GT-1202 measure corroded steel?

The Benetech GT-1202 may be suitable for certain corroded steel measurements when the material, surface condition and probe configuration are compatible.

Does calibration fix all thickness measurement errors?

No. Calibration does not automatically repair a damaged probe, connector or instrument.

How can I check whether my thickness gauge is accurate?

Verify the instrument using a suitable reference block and compare the reading with the known thickness according to the applicable procedure.

Where can I get assistance with ultrasonic thickness gauge problems in Malaysia?

Contact MTM Precision Sdn Bhd for product information, troubleshooting enquiries and available service options.

Benetech GT-1202 Ultrasonic Thickness Gauge Troubleshooting Malaysia

Reliable ultrasonic thickness measurement requires correct instrument settings, suitable probes, proper surface preparation and appropriate verification.

The Benetech GT-1202 Ultrasonic Thickness Gauge may be considered for compatible industrial thickness measurement applications.

If your instrument produces incorrect or unstable readings, identify the measurement conditions before assuming the instrument is defective.

MTM Precision Sdn Bhd supplies industrial testing and measuring instruments for factories, engineering companies, maintenance contractors and industrial customers in Malaysia.

For technical enquiries, provide:

Instrument model

Probe type

Material being measured

Expected thickness

Displayed thickness

Measurement surface condition

Photos of the instrument and probe

This information can help our team understand your application and advise on available options.

Contact MTM Precision Malaysia

Looking for Benetech GT-1202 Ultrasonic Thickness Gauge troubleshooting, industrial thickness measurement equipment, calibration enquiries or service information?

MTM Precision Sdn Bhd

Showroom & Service Centre

No. 29-1 & 2, Jalan Bandar 18,

Pusat Bandar Puchong,

47160 Puchong, Selangor, Malaysia.

Tel: 03-8080 7172

WhatsApp: +6016-660 7346

Email: mtmpre@yahoo.com

Website: www.mtmpre.com.my

Business Hours: Monday to Friday, 9:00 AM - 6:00 PM

For faster assistance, send us the instrument model, probe photos, displayed readings and measurement problem through WhatsApp.

If possible, include a photo or short video showing the issue.

MTM Precision - Industrial Testing, Measuring Instruments and Service Enquiries Malaysia