ADVANCED MATERIALS & PROCESSES | MAY/JUNE 2025 33 to ensure the weights drop correctly. This is a less critical matter when using a load cell system. Conforming to ASTM E18 superficial Rockwell hardness standards, hardness testers in this category offer excellent repeatability in all superficial Rockwell hardness scales. Superficial Rockwell hardness testing is designed for very thin and soft workpieces. The systems are suited for a wide range of environments including inspection labs, heat treat facilities, tool rooms, problems but also makes the equipment less sensitive to misalignments caused by vibrations. The systems are ideal for laboratories, workshops, tool rooms, and inspection labs. Software-driven digital optical systems offer advantages over manual microscopes that are supplied with several hardness testing machines. Connected to a PC, laptop, or tablet, the operator can push a single button to take automatic and instant measure- ments. All graphics can be saved, along with test results, in either Word or Excel formats. VICKERS AND KNOOP HARDNESS TESTERS Micro Vickers and Knoop hardness testers are cost-effective options in Vickers hardness applications that are ideal for those who do not perform high volume testing each day. Testing is done on extremely thin/small workpieces, and often used to check the hardness of layers, or platings and coatings on small parts in a laboratory environment. A high level of preparation is needed for such testing, including but not limited to, a high degree of polishing. There are two types of turret control including a basic manual turret for changing from optics to indentation and back to optics for measuring. A second type incorporates an automatic turret, giving operators greater freedom to change the turret position by either pressing a button on the keypad or via software control, depending on the software version used. The most popular Vickers and Knoop hardness testers have a turret control option using software to control the entire test with a one-click process using calibrated auto edge detection. Precision video and measure- ment software also allows for clicking of the indent edges in software, then deriving a hardness reading on screen. Designed for the accurate hardness testing of small precision parts, thin materials, case-hardened layers, and all sorts of steel components, Macro Vickers hardness testers utilize workshops, and laboratories. For more versatility, twin hardness testers are capable of testing in all the regular Rockwell and superficial Rockwell hardness scales. Dolphin nose systems allow for the hardness testing of inner, as well as exterior, diameters. The systems are generally larger in size than other bench Rockwell systems, offering greater testing heights and depths. Dolphin nose models have a manual handle that activates the preload system, or an advanced auto Z-axis preload system. Using the auto Z-axis preload system, the operator places the workpiece in testing position and presses the start button for the machine to complete the testing process. BRINELL HARDNESS TESTERS Brinell hardness testing is commonly used for very large, porous testing of less hard metals, such as castings. Benchtop systems available today can handle the most popular Brinell hardness applications and incorporate the latest innovative closed-loop technology. A test load is applied via a closedloop control unit with a load cell to apply weight loads up to 3000 kg, a DC motor, and an electronic measurement control unit. The result is highly accurate Brinell hardness measurements at all test loads up to 0.5%. A common weight load overshoot or under- shoot, also known as traditional dead weight or open loop, is eliminated. The absence of mechanical weights not only eliminates friction Fig. 2 — Digital Rockwell superficial hardness testers with fully automated load/unload procedures offer highly sensitive and accurate readings. Fig. 3 — Hardness testers provide Rockwell hardness values on all types of metal and alloys. There are two types of readouts offered for the mechanical machines, one with an analog dial face and one with a digital dial face. The digital face offers some functions such as limited conversions.
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