Ultrasonic Contact Impedance Hardness Testing

Ultrasonic contact impedance hardness testing is non-destructive and can be performed on difficult-to-test surfaces. With this method, you can easily measure indentation sizes and depths without damaging the workpiece.

Portable hardness testers are handheld devices that can be used on-site. These testers use LEEB rebound or ultrasonic contact impedance methods to determine metal hardness quickly and accurately.

Non-destructive testing

UCI testing uses a diamond indenter that is attached to the end of a vibrating rod. When the indenter is pressed against the test surface, it causes a shift in the rod’s frequency that is measured and converted into a hardness value. Because the indentation is microscopic, it is considered nondestructive.

These portable metal hardness testers can be used on a variety of metal materials and can make tests on all hardness scales. They are easy to operate and are ideal for use in a workshop or field environment. These units also include a camera that allows you to take a picture of the testing area and mark it with a hardness value.

Proceq’s Equotip portable hardness tester can use the dynamic rebound testing method according to Leeb, static Portable Rockwell or the Ultrasonic Contact Impedance (UCI) method. These rugged Swiss-made metal NDT instruments are capable of making hardness measurements on almost any object and can be used in the lab, workshop or production facilities.

Accuracy

Mobile hardness testing is typically done by manually positioning the measurement probe and then pressing it firmly against the material. Once the required test force has been applied, the device will indicate this visually and acoustically and automatically save and display the measured results.

UCI testing provides a highly accurate and non-destructive measurement of hardness. The measured values can be converted into common hardness scales, such as Rockwell, Brinell, Leeb, and Barcol. The UCI method also allows measurements to be taken on surfaces that are difficult to access, such as on complex-shaped parts or surface-hardened layers.

During calibration, the measurement probe is pressed against several hardness comparison plates. A conversion formula is then used to determine the elasticity module and cross-contraction number of the test sample. The coefficients a and b can then be determined from these values. These can be compared with the values obtained from the optical impressions and the correction factor is determined.

Speed

With a quick 2-second measurement time, the UCI method is much faster than traditional Vickers testing. This makes it ideal for weld inspection, hardness control of metal coatings and more.

UCI testing measures the changes df in frequency f of a resonator that are caused by different test forces and converts them into the hardness value HV using a conversion formula based on the modulus of elasticity E and transverse contraction ratio $g(m)$ of the tested material.

FOERSTER’s portable ultrasonic hardness testers use the ASTM A1038 Ultrasonic Contact Impedance (UCI) method. This allows you to measure the hardness of small forgings, cast materials, weld inspection areas, ion-nitride stamping dies and molds, forms, presses, thin-walled structures and parts, bearings and tooth flanks in any workshop or field condition. It is also ideal for a variety of other tasks that require speed and efficiency, such as quality assurance during production. It’s easy to use, and can be set up quickly with a “plug and measure” interactive interface and programming functions.

Portable

UCI hardness testing can be used to measure the hardness of objects with a complex shape (gear teeth, saw blades or various metal fasteners) or with thin walls (thicker than 1 mm). It also enables the measurement on positions that cannot easily be reached using a Leeb probe.

The diamond indenter of the UCI hardness tester leaves much smaller prints than a Leeb test. This makes it non-destructive and very portable. It is ideal for use on the job site, in workshop and field conditions.

The UCI method measures the comparative hardness of a material sample by measuring the change df in the frequency f of the resonator caused by the load on the diamond indenter. The measured change in frequency is then converted to a hardness value using a standard conversion formula. The measurement is quick and easy. The results are shown immediately on the display. The probe can be withdrawn when the measurement is complete and the instrument indicates this with an acoustic signal.