control-webseitenbanner.jpg§baq-anim-front.jpg§bq_anim_rockmod(dsc0307).jpg§bq_anim_start.jpg§bq_anim_dsc0256.jpg§bq_anim_alphadur_mini.jpg§bq_anim_ut200.jpg§bq_anim_alphadur_ii.jpg§bq_anim_shore_analog.jpg§bq_anim_shore_digital.jpg§bq_anim_kalo_max.jpg

Control 2018 - the International trade fair for quality assurance§Halle 4 - Stand 4220§24. - 27. April 2018§

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Vollautomatische Härteprüfung§ROCKWELLmodul§für die normgerechte Prüfung in der Produktion§2001

Mobiles Rückprall-Härteprüfgerät §dynaROCK II§für die schnelle und einfache Messung§1981

BAQ bietet ein breites Spektrum an §Schlaggeräten §für verschiedene Anwendungsfälle der Rückprall-Härteprüfung§

Mobiles UCI-Härteprüfgerät §alphaDUR mini§für die schnelle und einfache Messung§1976

Vollautomatischer UCI-Härtescanner§UT 200§für hochaufgelöste Härteverteilungen§2000

Universelles Härteprüfgerät§alphaDUR II§für Rückprall- und UCI-Messungen§1726

Durometer zur Härteprüfung von Kunststoffen§SHOREanalog§Shore A und D§1980

Durometer zur Härteprüfung von Kunststoffen§SHOREdigital §Shore A und D§1979

Kalottenschleifgeräte der Serie§kaloMAX§zur Schichtdicken- und Verschleißprüfung§1996

files/news/12/bild.jpg§https://www.hk-awt.de/§_blank§5000§Cologne 2018-10-16 - 2018-10-18§Stand A110§ 

files/news/1/bild.jpg§§§5000§ § § §

files/news/2/bild.jpg§template.cgi?page=artikel_detail&id=2001&lang=en§§5000§Fully automised hardness testing§ROCKWELLmodule§for standardized testing in the production

files/news/3/bild.jpg§template.cgi?page=artikel_detail&id=1981&lang=en§§5000§Mobile rebound hardness tester§dynaROCK II§for fast and easy testing

files/news/4/bild.jpg§§§5000§BAQ offers a large scale of§Impact Devices§for different applications of hardness testing

files/news/5/bild.jpg§template.cgi?page=artikel_detail&id=1976&lang=en§§5000§Mobile UCI-Hardness tester§alphaDUR mini§for fast and easy testing

files/news/6/bild.jpg§template.cgi?page=artikel_detail&id=2000&lang=en§§5000§Fully automised UCI-Hardness scanner§UT 200§for high-resolution hardness distribution

files/news/7/bild.jpg§template.cgi?page=artikel_detail&id=1726&lang=en§§5000§Universal hardness tester§alphaDUR II§for Rebound and UCI-Testing

files/news/8/bild.jpg§template.cgi?page=artikel_detail&id=1980&lang=en§§5000§Durometer for hardness testing of plastic§SHOREanalogue§Shore A and D

files/news/9/bild.jpg§template.cgi?page=artikel_detail&id=1979&lang=en§§5000§Durometer for hardness testing of plastic§SHOREdigital§Shore A and D

files/news/10/bild.jpg§template.cgi?page=artikel_detail&id=1996&lang=en§§5000§Calotester of the series§kaloMAX§for determination of layer thickness and wear resistance

control-webseitenbanner.jpg§baq-anim-front.jpg§bq_anim_rockmod(dsc0307).jpg§bq_anim_start.jpg§bq_anim_dsc0256.jpg§bq_anim_alphadur_mini.jpg§bq_anim_ut200.jpg§bq_anim_alphadur_ii.jpg§bq_anim_shore_analog.jpg§bq_anim_shore_digital.jpg§bq_anim_kalo_max.jpg

Control 2018 - International trade fair for quality assurance§Halle 4 - Stand 4220§24. - 27. April 2018

 § § 

Fully automised hardness testing§ROCKWELLmodule§for standardized testing in the production§2001

Mobile rebound hardness tester§dynaROCK II§for fast and easy testing§1981

BAQ offers a large scale of§Impact Devices§for different applications of hardness testing§

Mobile UCI-Hardness tester§alphaDUR mini§for fast and easy testing§1976

Fully automised UCI-Hardness scanner§UT 200§for high-resolution hardness distribution§2000

Universal hardness tester§alphaDUR II§for Rebound and UCI-Testing§1726

Durometer for hardness testing of plastic§SHOREanalogue§Shore A and D§1980

Durometer for hardness testing of plastic§SHOREdigital §Shore A and D§1979

Calotester of the series§kaloMAX§for determination of layer thickness and wear resistance§1996


 
 
 

Measuring Methods

Hardness testing:

The UCI-Method
The Leeb hardness testing method
The Ultrasonic-Backscattering-Procedure

Determination of layer thickness:

Determination of layer thickness with a spherical cap grinder (Calotest)





Hardness testing - The UCI method

The UCI method (Ultrasonic Contact Impedance) is successfully used in hardness testing since many years. The probes of the alphaDUR II or alphaDUR mini and the Hardness scanner UT200 work according to this method. A rod is excited into a longitudinal oscillation. At the tip of the rod, a Vickers diamond is placed. This diamond is pressed to the specimen with a discrete test load. Mostly the test load F is applied through a spring. The rod oscillates with its self-resonant frequency which depends essentially on its length. When the Vickers diamond penetrates the specimen, the oscillation of the rod is damped. This causes a shift Df of the resonance frequency, which can easily be measured.



The damping of the rod and the resulting shift in resonance frequency depends on the size of the area of contact between the diamond and the specimen and therewith on the hardness of the material if the test load is constant. Beneath the hardness, the elastic modulus of the material also affects the frequency shift. The hardness of the material can be calculated from the known test load, the measured frequency shift and the material calibration factor (for taking the elastic modulus into account). The advantages of the UCI method are the ease of automation and the very good reproducibility of the hardness readings. The reproducibility of the measurements is better than with optical methods of hardness testing because the total area of contact (proportional to d2) enters into the measurement and not only the diagonal d or a diameter. Moreover the measurement results are independent from the subjective view of a single examiner and the test is very fast executable. For carbon steel and low alloyed steel, hardness reference samples are used for purpose of calibration. The low variation of the elastic modulus of this group of materials can be neglected. For defining the necessary testload of the UCI-Probe in accordance to the hardness of the samples and the desired intendation diagonals or penetration depth please use the Diagram Penetration depth. The layer thickness (or depth of the hardening) should be 10 times higher than the penetration depth.
Further Informationen for UCI-Hardness testing: Specimen requirements, Selection of the right UCI-Probe, Minimum thickness and mass of the workpiece, Execution of a measuring UCI-Information-sheet (PDF-Download).

Hardness testing – the Leeb hardness testing method

The Leeb hardness testing method is a dynamic hardness testing procedure. The portable hardness testers dynaROCK II and Hartipp1800B work according to this procedure.
Over the spring force a impact device (Carbide balls, for special applications a diamond tip) is fired onto the sample surface. The measurand is the difference between the impact and rebound speed of the impact body. The loss of the velocity is directly related to the hardness, taking account of the calibration and in accordance to influence of the mass and the surface of the sample.
Further Informationen for Leeb-Hardness Testing (Rebound): Specimen requirements (Mass, wall thickness, roughness), Selection of the right impact device, measuring accuracy. Leeb-Information-sheet (PDF-Download).


The Ultrasonic-Backscattering-Procedure

For the measuring of the depth of the hardening of heat-treated parts, the Ultrasonic-Backscattering-Procedure is very suitable. Thereby the differences in the grain structure between the case and the core are used. While the hardened case shows a very fine-grained Martensite-structure the core has, depending on the pretreatment, a coarser core. This means that at the transition to the core a higher sound scattering occurs, owing to the coarser grain-structure.
The procedure works with oscillating-impulses, which frequency is 20 MHz, so that the scattering for the measuring is sufficient. The oscillating-impulses are created by the measuring electronic and emitted by a test head. The backscattered sound intensity is captured by the same test head and analyzed by the measuring electronic.
Therewith the soundwaves can get into the work piece, a medium between the test head and the work piece which can transport the ultrasonic-impulses, is necessary. Air is not suitable for this procedure. Due to this, the parts are measured in a water bath, where a corrosion inhibitor is added if needed.
The soundwaves spread as longitudinal waves in the water. If they hit the work piece surface in a defined angle, they were converted into transverse waves, which can spread in steel. At the surface of the work piece a part of the sound intensity is reflected and hits the test head again. The duration of the radiated sending-impulse is essentially shorter than the runtime of the signal from the test head to the surface and vice versa. Owing to this, no overlays between the sended and the received signal occurs.
The entered soundwaves travels unimpeded through the hardened marginalized layer, so that barely no soundwave are backscattered and hit the test head from this area.



First at the border to the base material the backscattering increases abrupt. The sound signal is partially reflected into the direction of the test head. At the surface the transverse waves are reconverted into longitudinal waves, which are spreading in the water and reach the test head.
The measuring electronic records the receive-signal from test head constantly. The signal curve contains a strong surface echo, then a minimum and subsequent a more or less steep rise which results of the reflection at the transition from the marginalized layer to the core material.

For measuring the depth of the hardening, the distance between the surface and the boundary layer in millimeters has to be determined out of the signal curve. The runtime of the sound between the surface and the boundary layer can be determined from the measuring curve. Here the time between the maximum of the surface echo and the first rise of the signal after the minimum is used for evaluation. With the known sonic speed in steel the migration distance in millimeters can be calculated.

Determination of layer thickness with a spherical cap grinder (Calotest)

With the layer thickness measuring device kaloMAX II the layer thickness is determined purely geometrical.


With a steel ball a spherical cap is ground through the layer on the sample into the base material.
h - desired layer thickness
R - Radius of the ball
T - total penetration depth of the ball
t - depth of penetration in the base material
D - diameter of the spherical cap at the surface of the sample
d - diameter of the boundary between coating and base material

The total penetration depth of the ball is:


The depth of penetration in the base material is:


The thickness of the layer results from the difference:


If the layer is very thin and the spherical cap is ground into the base material only a little, the diameters D and d are very small compared to the radius of the ball. In this case the equation can be simplified to:


This formula shows, that the accuracy of layer thickness measurement by means of spherical cap grinding depends on the accurate measurement of the two diameter D and d, because the error of R is less then 1 ‰. Furthermore the meticulous measurement of the two diameters is important because the square of these items is used in the calculation. In general, the spherical cap should not be ground too deep into the base material in order to achieve high accuracy.

When the sample is cylindrical, the shape of the spherical cap is elliptic instead of circular. The calculation of layer thickness can be done with the same equations as for plane samples but it is essential to take D and d from the longitudinal axis of the ellipse.