How to Test the Hardness of Quenched and Tempered Round Steel

1. Sample Preparation and Surface Treatment Before Testing
First, select a representative sample of quenched and tempered round steel. Ensure that the sample section reflects the overall material properties and avoid areas with cracks, scratches, or surface damage. Then, prepare the sample surface by grinding and polishing to remove surface scale, oil stains, and processing marks. This ensures a smooth and even surface. This prevents surface impurities or rough textures from interfering with pressure transmission during hardness testing, ensuring accurate test data.
2. Selecting an Appropriate Hardness Testing Method
Select an appropriate hardness testing method based on the application and standard requirements of the quenched and tempered round steel. Commonly used methods include Brinell hardness testing and Rockwell hardness testing. The Brinell method is suitable for testing quenched and tempered round steel with lower hardness or thickness, using a spherical indenter to apply pressure and measure the indentation diameter. The Rockwell method is suitable for testing quenched and tempered round steel with higher hardness, using a diamond cone indenter to measure the indentation depth. Both methods use specific principles to determine material hardness, so the choice should be based on actual needs.

3. Perform Hardness Testing in a Standardized Manner
Secure the processed sample onto the testing equipment workbench, ensuring it is stable and free of movement. Adjust the equipment parameters according to the test method so that the indenter applies pressure at the specified speed and maintains pressure for the specified time before unloading. After unloading, use the equipment's built-in measurement system to read the indentation dimensions and convert the hardness value according to the corresponding formula or standard. Avoid external interference during this process to ensure that each step complies with specifications.

4. Compare the hardness value to the standard to determine if the hardness meets the requirements.
After the test is completed, compare the hardness value with the corresponding industry standard or customer-specified hardness range for the quenched and tempered round steel. If the test value is within the specified range and the fluctuation between multiple test results is minimal, the hardness of the batch of quenched and tempered round steel passes the test. If the test value is outside the range or fluctuates significantly, retest the sample to investigate any operating errors or uneven material properties to ensure reliable results.

If you require information on hardness testing methods for quenched and tempered round steel, please contact Jiangsu Zhongao New Steel Technology, where we have extensive repair experience.