UCI hardness testing is suitable for incoming goods inspection, production control or maintenance on integrated components. Using cable-connected pin-shaped slim UCI measurement probes with standard test loads, tests can be carried out in all directions or in areas that are difficult to reach.
The UCI method measures the frequency shift of vibration in the material and determines the corresponding hardness value. It does not leave a visible indentation like the traditional Vickers hardness tester method.
The UCI method measures the comparative hardness of metallic samples using an ultrasound technique. It is based on the frequency shift in the mechanical resonant frequency of the probe due to the contact between the Vickers diamond indenter on the end of the test instrument and the material being tested.
The frequency increase depends on the material being tested, as well as the mechanical parameters of the probe (coupling strength and Young’s Modulus). The influencing factors are determined during the calibration of the device using test blocks made of different metal materials.
FOERSTER offers mobile UCI hardness testers for the most diverse applications. The portable SONODUR 3 can be used with cable-connected UCI probes of the SONO-H/M/S series in various versions and test loads (10 N, 49 N, 98 N). The SONODUR 3 is also equipped with optional weights for increasing the test force by moto. This allows the device to be used for testing difficult-to-access positions and component geometries such as tooth flanks or root areas.
Young’s modulus, also called the elastic modulus or tensile modulus is a physical property of linear elastic materials like rods, wires and such. It describes how easy it is to bend or stretch the material. It is one of the most important numbers when it comes to material properties.
The UCI method invented by Claus Kleesattel is based on the measurement of the change in the frequency f of the resonance vibration caused by the coupling between the Vickers diamond and the test material. Unlike the classic hardness testing methods, the UCI method is independent of the measuring force and mechanical parameters of the probe. The influencing factors come only from the material being tested, namely the rod property “k”, the coupling strength and the effective Young’s modulus determined from the diamond and material.
The adjustment of a UCI instrument to materials with deviating Young’s modulus has been simplified by means of a comparative measurement using the new one-point adjustment system. This procedure is much faster than the traditional calibration of a hardness tester and does not require any additional measuring plates.
UCI hardness testing is used to measure the elastic properties of materials under load. The measured frequency change df of the mechanical resonator is inserted in a conversion formula, together with known values for the modulus of elasticity E and transverse contraction ratio g, to determine the hardness value HV.
Coupling strength can be optimized by tuning the bias field angle of the resonator. Fig. 23 shows a transmission spectrum at th = 0deg and th = 90deg, with the solid curves representing fits according to Eq. (64).
The measuring process is quick and does not harm the sample. This makes it ideal for incoming goods inspection, mix-up checks and production control, even in areas that are difficult to access with conventional Vickers tests. It is also possible to perform measurements on metals with a complex forms and thin walls, such as gear teeth and saw blades. The NOVOTEST T-U2 offers a manual or motorized measurement probe and an instrument to assess, save and compare the measured values.
The UCI method measures the resonant vibration frequency of the diamond in contact with the test material, as well as the resulting change in the oscillation frequency at the point of impact (frequency shift). This measurement data can be converted into hardness values.
The system of the SONODUR 3 with cable-connected SONO-H/M/S series probes can be used for mobile UCI hardness testing. The portable device with its flexible application possibilities is ideal for weld inspection, heat-affected zone, ion-nitride stamping dies and molds, thin-walled parts, bearings, and tooth flanks as well as in the field, workshop or laboratory.
The comparability to the standardized classic Vickers hardness scale and the immediate conversion into all common hardness scales make the UCI testing method ideal for incoming goods inspection, mix-up checks and quality assurance in production. Unlike Dynamic Impact testers, UCI testers can also be used in difficult test positions and for complex component geometries such as the base of gear teeth.