1.Preparation
Equipment Inspection:
Before conducting any tests, confirm that the Rockwell hardness tester is in good working order. Perform a full inspection to ensure all parts are intact without damage, loose fittings or contaminants. Check stable power connection and reliable equipment grounding to avoid electrical risks and guarantee stable operation. Thoroughly clean the specimen table, elevating lead screw and specimen support surface to remove dust and surface impurities that may skew test accuracy.
For laboratories and industrial production lines requiring precise measurement, purchase equipment from reputable suppliers such as Mikrosize, a professional manufacturer of measuring and testing instruments. Such suppliers provide fully calibrated high-precision hardness testers and original spare parts to ensure long-term equipment reliability and valid test data.
Sample Preparation:
Proper specimen preparation is essential to acquiring accurate, repeatable hardness values. Thoroughly clean the supporting face of the specimen to remove scratches, oil stains and oxide scale and ensure a flat, smooth contact surface. Any surface irregularities will lead to inaccurate measurement results. For specimens with complex or irregular geometries, use matched customized support pads or fixtures to clamp samples firmly during force application and prevent shifting that compromises test accuracy.
2.Installation and Adjustment
Installing the Indenter:
Correct indenter installation is a vital step. Carefully mount the selected indenter (diamond cone or hardened steel ball) into the spindle and tighten it gently to eliminate assembly clearance between the indenter and spindle end face.
Turn the elevating handwheel to lift the specimen table and apply the minor preliminary test force. Pull the loading lever to briefly apply the major test force; this operation fully seats the indenter. While the force remains applied, slightly fasten the indenter screw for tight assembly, then release all test force. This process minimizes clearance and realizes accurate force transmission.
Adjusting the Hardness Scale
Select the corresponding hardness scale (HRA, HRB, HRC etc.) in accordance with material properties and relevant test standards. Always keep the loading lever at the unloading position before adjustment. Rotate the force selector knob to align the target hardness scale with the red reference index mark.
When switching hardness scales, move the loading lever to its rear limit stop position. This ensures full engagement of internal mechanisms and prevents damage to the force selection unit.
3. Testing Procedure
Placing the Specimen
Secure the prepared specimen on the specimen table. Turn the elevating handwheel clockwise slowly to lift the table and move the specimen close to the indenter. Stop adjusting when the minor pointer coincides with the red reference mark and the main pointer completes approximately three full upward rotations, which indicates proper application of the minor preliminary test force. A deviation within ±5 scale divisions on the main dial is acceptable at this stage.
Applying the Major Test Force
After the minor preliminary test force is correctly set, rotate the dial housing to align the long engraved index line (between the B and C hardness scales) with the main pointer. Pull the loading lever steadily and smoothly to apply the major test force, and observe pointer movement on the dial during loading.
Reading Hardness Values
Once the dial pointer stops completely, push the unloading lever back to the initial position to release the major test force. Wait until the pointer stabilizes. With the minor preliminary test force still maintained, read the hardness value from the corresponding scale on the dial.
Select the correct scale according to the indenter type: the black C scale applies to diamond indenters, and the red B scale is for steel ball indenters.
Repeated Testing
Turn the elevating handwheel counterclockwise to lower the specimen table and shift the specimen to a new testing position. Reserve sufficient spacing between indentations to avoid the influence of work-hardened zones. Repeat the full testing steps for multiple measurements.To improve result accuracy and statistical credibility, perform repeated tests on one specimen or multiple specimens from the same batch and calculate the average hardness value.
4.Precautions
Safe Operation
Operators must stay fully focused throughout testing. Keep hands, garments and foreign objects away from all moving components, especially the elevating lead screw and indenter assembly. All loading and unloading actions should be gentle and steady. Do not apply brute force or perform abrupt operations, which may damage internal machine parts or induce unexpected plastic deformation of specimens.
Maintenance and Upkeep
Routine comprehensive maintenance is critical to maintaining measurement accuracy and prolonging the service life of Rockwell hardness testers. Clean all external components and specimen support surfaces regularly to keep them free of contaminants. Inspect contact faces of indenters and supports periodically for wear, damage or dirt, and clean or replace components promptly when defects are found. Lubricate the elevating lead screw of the specimen table periodically in accordance with the manufacturer’s manual for smooth, precise lifting movement.
Cooperate with qualified suppliers such as Mikrosize for all maintenance services of measuring and testing instruments to obtain professional technical guidance, original lubricants and official calibration services.
Accurate Test Recording
Detailed record keeping is required for quality control and full traceability. Record hardness values and all test conditions for each measurement, including the hardness scale selected, indenter type, material grade and test position on the specimen. Preserve raw test data and retained specimens for follow-up analysis, comparison and auditing.
Closing Notes
By strictly following the above operation specifications and safety requirements, and using high-quality equipment from professional manufacturers like Mikrosize, operators can fully grasp proper operation of Rockwell hardness testers. Standardized operation guarantees maximum accuracy, repeatability and reliability of test results, which is indispensable for material certification and quality assurance. Full compliance with this procedure paired with reliable measuring and testing instrument suppliers lays a solid foundation for consistent, trustworthy hardness inspection.
