Hardness By Portable Tester

What is Hardness Testing?

Hardness testing is a method used to measure a material’s resistance to indentation, penetration, or scratching.
In NDT and field applications, portable hardness testers are widely used because they allow on-site, quick, and non-destructive measurement of hardness without cutting samples.

Principle of Portable Hardness Testing

Portable hardness testers work on different principles depending on the device type:

1. Rebound (Leeb) Method:

   • A tungsten carbide ball or diamond tip impacts the material.

   • The rebound velocity is measured.

   • Harder materials give higher rebound values.

2. Ultrasonic Contact Impedance (UCI) Method:

   • A vibrating probe with a diamond indenter is pressed onto the surface.

   • Frequency shift indicates hardness.

   • Suitable for thin components and coatings.

3. Portable Rockwell Method:

   • Directly applies a load using a small portable tester.

   • Measures indentation depth similar to lab Rockwell machines.

Types of Portable Hardness Testers

• Leeb Hardness Tester (HL values).

• UCI Hardness Tester.

• Portable Rockwell Hardness Tester.

• Digital Multi-Scale Testers (convert readings into HB, HV, HRC, etc.).

Step-by-Step Procedure

1. Surface Preparation – Clean and smooth the surface (free from rust, paint, dirt).

2. Select Testing Method – Leeb, UCI, or Portable Rockwell depending on application.

3. Calibration – Calibrate instrument with reference blocks.

4. Testing – Place the probe/indenter on the material and take readings.

5. Repeat – Perform multiple tests for accuracy.

6. Result Interpretation – Average results and convert into standard hardness scales (Brinell, Rockwell, Vickers).

Applications of Portable Hardness Testing

• On-site inspection of pipelines, tanks, and vessels.

• Weld hardness verification.

• Heat treatment quality checks.

• Large machine components (shafts, rollers, gears).

• Aircraft, automotive, and power plant components.

Advantages

• Portable, quick, and easy to use.

• Non-destructive (no significant surface damage).

• Converts to multiple hardness scales.

• Ideal for large or fixed components.

Limitations

• Less accurate than laboratory hardness testing.

• Requires proper surface finish.

• Limited use on very thin or small parts.

• Operator skill affects accuracy.

Standards & Codes

• ASTM A956 – Leeb hardness testing.

• ASTM E110 – Portable hardness testers.

• ISO 16859 – Leeb hardness testing standard.

✅ Summary:
Portable hardness testing is a fast and reliable method to measure hardness on-site without cutting or damaging the material. With Leeb, UCI, and portable Rockwell testers, industries can ensure material properties meet specifications in real-time quality control and maintenance checks.