ADL-DU110. Universal Hardness Tester

Hardness is understood as a material’s property to resist the penetration of another body that does not result in residual deformations.

Hardness testing is the most widespread and high-productivity non-destructive testing method for materials, serving as a reliable and versatile approach for the physicochemical analysis of properties in the examined material.

The most common methods of hardness measurement include Brinell, Rockwell, and Vickers measurements.

During hardness measurements, portable devices do not disrupt the galvanic coating or the surface layer of the object that has undergone chemical, thermal, or mechanical treatments (such as plating, aging). On the other hand, stationary hardness testers exert significant pressure that can “indent” these layers.

A dynamic hardness tester is recommended for measuring the hardness of solid objects (with a mass of 3-5 kg) having sufficient wall thickness at the measurement point (around 5-8 mm). Measuring the hardness of lighter objects or those with thinner walls is possible, but in such cases, additional steps are required (e.g., pressing the object against a solid plate through a layer of contact liquid or using some other method of rigid fixation for control purposes). Among the advantages of dynamic hardness testers, lower surface preparation requirements at the measurement point should be noted.

An ultrasonic hardness tester is recommended for measuring the hardness of objects with complex geometric shapes (such as gear teeth, saw teeth, various fasteners, etc.), low mass (starting from 10 grams), and thin walls. In cases where using a dynamic hardness tester is not possible or requires additional procedures, an ultrasonic hardness tester is suitable. Advantages of ultrasonic hardness testers include the capability to measure hardness in surface-hardened layers and the measurement of hardness for objects with intricate shapes, low mass, and wall thickness.

Before commencing measurements, it’s essential to check the readings of the portable device against standard hardness measures. If the device’s readings fall within the hardness range, it can be used for measurements. However, if the readings significantly differ, calibration of the device is required. After calibration, standard hardness measures should be remeasured to ensure accuracy.

The primary prerequisites for conducting hardness measurements on a finished product using a portable hardness tester include:

• Surface roughness of the product
• Mass of the product
• Thickness of the product

All product requirements are specified in the ASTM A956 Standard Test Method for Leeb Hardness Testing of Steel Products (dynamic sensor) and the ASTM A1038 Standard Test Method for Portable Hardness Testing by the Ultrasonic Contact Impedance Method (ultrasonic sensor).