Case Hardening is the heat Treatment Process for Steel, it is one of the Surface Duffision Engineering. Presently, we measure the Case Depth by Destructive Testing Method so that the material of the tested part is cutted and Polished then Etched and viewed by Metallurgical Microscope then Interpret the Diffusion Layer i.e Case Depth, it is very difficult to measure 100% of the component Non destructively.
I would like Interested to determine the Case Depth and Hardness by Nondestructive Technique of Ultrasonic Testing.,
This is a very interesting question. In theory yes you can obtain a sense of the hardened depth, however, in practice this needs a careful pre-calibration and testing of different models to come out with precise measurement that suit your application. Remember that in general, case hardened steel will have a depth of 2-3 mm so we are talking about 1mm difference and your measure should come out with far higher precision to make such application useful. Of course different materials and different cooling rate will produce different hardness (and different microstucture) therefore if all parameters are kept constant apart from only one single parameter that affect the hardened depth than you will have a better change to make your application successful.
I hope the above help.
Best regards
The ultrasonic testing depends on the reflection of the sound waves at defects/ anomalies in the material. So the nature of the case as well as the substrate would affect the response of Ultrasonics.
If you are looking at alternative NDT techniques, Please go through the attached link.
Hope this helps.
http://www.izfp.fraunhofer.de/content/dam/izfp/de/documents/aktuelles/2015/Themenflyer/3MA-Grundlagen-en.pdf
Dear Shri Anand Pai,
Thank you for your immeadiate response, i unable to recive your attached link, I request you to kindly send me the link once again.
Regards,
P.Kuppuraj
There are few papers in the net which deals with this subject. This means that definitely this is possible.
1-NONDESTRUCTIVE DETERMINATION OF HARDENING DEPTH IN INDUCTION HARDENED
COMPONENTS BY ULTRASONIC BACKSCATTERING
H. Willems
2-Method of case hardening depth testing by using
multifunctional ultrasonic testing instrument
Y A Salchak1, , D A Sednev1, , M Kroening2, and I B Ardashkin
They may help
Hi,
Case-depth measurement using Low frequency Magnetic Barkhausen Noise would be successful for case-depth upto about 1 to 1.5 mm.
Recently, I have used a new, but very simple approach based on Distortion analysis of Magnetic Excitation (DAME) voltage for case-depth measurements in carburised and Nitrided samples.
Ultrasonic back scattered technique would be useful only for induction hardened parts (with sharp gradient in HV profile) and successful only when case-depth is greater than 2 mm. It does not work well for shallow case-depth.
You may refer to my papers in Research gate using MBN and DAME methods.
If you could not find, please contact me.
Best wishes
Moorthy
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