Hardness Tester Operating and Calibration Guide
Hardness testers measure the resistance of a material to indentation. They are widely used in metallurgy, manufacturing quality control, and failure analysis.
I. Test Methods
- Rockwell: Measures depth of indentation under load. Fast and direct reading. Multiple scales for different materials (HRC for hardened steel, HRB for softer metals).
- Brinell: Uses a larger indenter for testing coarse-grained or heterogeneous materials. Requires optical measurement of indentation diameter.
- Vickers: Uses a diamond pyramid indenter. Suitable for all materials from very soft to very hard. Requires optical measurement.
- Portable/Leeb: Rebound method for field hardness testing. Convenient for large parts but less accurate than bench methods.
II. Calibration
- Verify the tester using certified hardness reference blocks at the appropriate hardness range
- Take multiple measurements across the reference block. The average should be within the tester accuracy specification.
- Check indenter condition and replace if worn, chipped, or cracked
- Verify load application using a force gauge or load cell
III. Operating Procedures
- Ensure the test surface is clean, smooth, and perpendicular to the indenter axis
- Support the specimen rigidly to prevent deflection during load application
- Select the appropriate scale and load for the material being tested
- Take multiple readings and report the average for representative hardness values
IV. Maintenance
- Keep the tester clean and free of dust and metal particles
- Inspect the indenter before each use; replace if worn or damaged
- Verify calibration daily with reference blocks before production testing
- Lubricate mechanical components per manufacturer specifications
