Leeb hardness testerDue to its portability and easy operation, it is widely used in metal hardness testing. Measurement errors can directly affect data accuracy. Mastering the following methods can effectively eliminate errors.
Standardize the surface treatment of test specimens, which should be smooth, free of oxide scale, rust, oil stains, and processing patterns. If the surface is rough, sandpaper can be used to polish it to Ra0.8~1.6 μ m; When there is oil contamination, wipe it clean with anhydrous ethanol or acetone and let it dry. At the same time, avoid measuring at the edges and thin walls of the specimen to prevent stress concentration from causing numerical deviation.
Ensure that the impact device is perpendicular to the surface of the specimen and strictly prohibited from tilting when measuring the correct operating posture. Apply pressure evenly and avoid excessive force or shaking. It is recommended to take the average of 3-5 impacts to reduce accidental errors in a single measurement. In addition, the same measuring point cannot be repeatedly impacted to prevent deformation of the specimen surface from affecting subsequent readings.
Perform equipment calibration and environmental control regularly using standard hardness blocks to calibrate equipment. The calibration steps should strictly follow the instructions to ensure that the ball head of the impact device is not worn or loose. The measurement environment temperature should be controlled between 10 ℃~35 ℃ to avoid high temperature, low temperature or electromagnetic interference; A hardness tester that has not been used for a long time should be preheated for 10-15 minutes before use.
Reasonable selection of impact devices and specimens with different materials and thicknesses and conversion coefficients should be matched with corresponding models of impact devices (such as D-type and C-type), and the correct hardness conversion coefficients (such as Brinell and Rockwell conversion) should be selected in the equipment to avoid system errors caused by incorrect parameter settings.