15th Asia-Pacific Conference for Non-Destructive Testing (APCNDT2017) Singapore, November 16, 2017

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Josephine Ann Conley
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Advancements of ultrasonic contact impedance (UCI)

during the indentation process, and practical benefits

(APCNDT2017) Singapore, November 16, 2017 C. Frehner, R.

1 Advancements of ultrasonic contact impedance (UCI) hardness testing based on continuous load monitoring during the indentation process, and practical benefits 15th Asia-Pacific Conference for Non-Destructive Testing (APCNDT2017) Singapore, November 16, 2017 C. Frehner, R. Mennicke, F. Gattiker, D. Chai* Proceq SA and Proceq Asia Pte Ltd. Proceq

UCI is one of the most commonly used portable testing methods Portability: small probe, even smaller nozzle Simplicity: straightforward use, incl.

2 UCI is one of the most commonly used portable testing methods Portability: small probe, even smaller nozzle Simplicity: straightforward use, incl. uneven surfaces Speed: short measurement cycle time Proceq 2017 Advancements of UCI hardness testing based on continuous load monitoring during the indentation process 2

Ultrasound excitation is used to determine the hardness of the test piece Longitudinal oscillation of resonating rod Vickers indenter forced into test piece Measured frequency shift ~ material

3 Ultrasound excitation is used to determine the hardness of the test piece Longitudinal oscillation of resonating rod Vickers indenter forced into test piece Measured frequency shift ~ material properties Dynamic principle probe and materialdependent conversion curves Proceq 2017 Advancements of UCI hardness testing based on continuous load monitoring during the indentation process 3

International standards ASTM A1038 and DIN 50159 specify UCI in detail UCI frequency shift is an indirect measure of indentation size Indentation size measured directly in stationary Vickers method

4 International standards ASTM A1038 and DIN specify UCI in detail UCI frequency shift is an indirect measure of indentation size Indentation size measured directly in stationary Vickers method Stationary Vickers method uses diamond indenter Diamond indenter in UCI: same tip shape as in stationary Vickers Hardness scale: HV, indicated as HV(UCI) Proceq 2017 Advancements of UCI hardness testing based on continuous load monitoring during the indentation process 4

Compared to stationary methods, UCI is fast, orientation-independent, precisely positioned Probe can be used in any orientation Orthogonal to surface Precise positioning, high accessibility

5 Compared to stationary methods, UCI is fast, orientation-independent, precisely positioned Probe can be used in any orientation Orthogonal to surface Precise positioning, high accessibility Diamond indenter Thin and long nozzle Only 1-2 seconds of load application Proceq 2017 Advancements of UCI hardness testing based on continuous load monitoring during the indentation process 5

UCI is often used to test hard-to-access and

2017 Advancements of UCI hardness testing based

6 UCI is often used to test hard-to-access and small pieces Heat-affected zones of welds Gear teeth Bearings Image source: Wikipedia Image source: Wikipedia Image source: Wikipedia Proceq 2017 Advancements of UCI hardness testing based on continuous load monitoring during the indentation process 6

For UCI, test pieces must fulfill requirements on thickness, mass, surface roughness Thinner / lighter pieces: Oscillations Ultrasonic wave reflections Adhesive coupling

7 For UCI, test pieces must fulfill requirements on thickness, mass, surface roughness Thinner / lighter pieces: Oscillations Ultrasonic wave reflections Adhesive coupling to thicker / heavier pieces Average roughness depth 5 μm Proceq 2017 Advancements of UCI hardness testing based on continuous load monitoring during the indentation process 7

The UCI nozzle must be used orthogonally to the test piece surface Deviation from 90 angle: biased hardness readings Small indentations in hard materials: may allow probe movement during testing ± 5

8 The UCI nozzle must be used orthogonally to the test piece surface Deviation from 90 angle: biased hardness readings Small indentations in hard materials: may allow probe movement during testing ± 5 vs. the surface normal is allowed by the standards Limitation more relevant as test loads increase Proceq 2017 Advancements of UCI hardness testing based on continuous load monitoring during the indentation process 8

9 New Proceq probe with adjustable test load reduces the need for multiple probes Test load Typical application HV10 HV5 HV1 Cast material, forgings, weld inspection General UCI applications, machine parts, shafts, weld inspections, etc. Thin-walled parts, coatings, bearings, tooth flanks, etc. Since 2016: latest generation of UCI probes Integrated load sensor Test load set before first reading of the series A single probe can flexibly cover multiple applications in the same environment. Proceq 2017 Advancements of UCI hardness testing based on continuous load monitoring during the indentation process 9

10 The integrated load sensor monitors the test load application and the frequency shift Complete indentation process monitored and logged: Speed of applying the load Load curve User guided through all the steps of the process reduced user dependence Constant and continuous load application stable, reliable and repeatable results Proceq 2017 Advancements of UCI hardness testing based on continuous load monitoring during the indentation process 10

11 Test load [N] Monitoring of test load vs. frequency shift allows better material characterization HV5 547 HV5 859 HV5 Left flank: indentation process Right flank: release of the probe Characterization of the plastic deformation '500 91'000 91'500 92'000 92'500 93'000 Resonating frequency [Hz] Instrumented indentation hardness test with a portable UCI probe Proceq 2017 Advancements of UCI hardness testing based on continuous load monitoring during the indentation process 11

12 Tests reveal the benefits of user guidance during measurements with the new UCI probe Standard deviation on test block 864 HV5 Tester 1 Tester 2 Tester 3 Tester 4 Tester 5 Tester 6 w/o w user guidance 6 users, little to no UCI prior experience User guidance: on vs. off Setup: Calibrated test block HV5 test load 12 readings per person Measure of repeatability: standard deviation after removal of 2 outliers Proceq 2017 Advancements of UCI hardness testing based on continuous load monitoring during the indentation process 12

New UCI probes with continuous load monitoring provide a swath of benefits One probe covers multiple applications Test load can be adapted to the application Measurement process can be precisely

13 New UCI probes with continuous load monitoring provide a swath of benefits One probe covers multiple applications Test load can be adapted to the application Measurement process can be precisely analyzed User guidance with hints and warnings Quality of measurement quantified, stored Significantly improved repeatability Proceq 2017 Advancements of UCI hardness testing based on continuous load monitoring during the indentation process 13

Performance of phased array and conventional ultrasonic probes on the new ISO reference block

Performance of phased array and conventional ultrasonic probes on the new ISO 19675 reference block C. Udell, D. Chai 1 and F. Gattiker Proceq S.A., Ringstrasse 2, Schwerzenbach, Switzerland. More info