Using & Calibrating Ultrasonic Micrometer

I am looking for some information / assistance in the use and calibration of ultrasonic micrometers.

We have been using an ultrasonic micrometer to verify the thickness of a coil steel strip in our pickling line. The US Micrometer calibration frequency was 365 days. We send it out for "calibration" to original place of purchase, also a 17025 cal lab. When it came back from them we started having some on and off problems with it's readings running from .003" / .010" higher than it should have been reading. Inquiries to the Calibration & Sales source resulted in us being told that we have to use the alloy compensation in order to get accurate readings in different grades of mild steel, (ie:1010 - 1050, 050, etc), which we have never done.

We have gone back to a manual check of the strip using a deep throat micrometer until we can resolve this issue and develop a degree of confidence in it's output.

We are using a CL 400 - Krautkramer. Any help we can get will be greatly appreciated.

Hello, Bigfoot. BTW, I have a size 16, can you beat that?


When you sent the micrometer in for calibration, did they make any adjustments of any kind?

I'm not real familiar with this piece of equipment. Is the mfg. still around? While they are usually not one of my first sources for calibration, it may be in order in this situation.

Hi Bigfoot,

Ultrasonic micrometers such as this Mitutoyo MU-Gage Sries 179 call for a different transducer to be used for aluminum and steel. With its proper transducer and step block for calibrating, I have not seen the need for compensating for ferrous and nonferrous metals.

No I can't 13 EE. When I contacted the calibration service they said no adjustments were made. It was OK as received. They suggested we try using the coupler more frequently without knowing the frequency we were using it. I've had the same person using this unit for the last 3 years without incident until now. I haven't tried contacting the manufacturer yet, but will likely end up doing so. Thanks for the suggestion though.

Jennifer Kirley said:

Hi Bigfoot,

Ultrasonic micrometers such as this Mitutoyo MU-Gage Sries 179 call for a different transducer to be used for aluminum and steel. With its proper transducer and step block for calibrating, I have not seen the need for compensating for ferrous and nonferrous metals.

Click to expand...

Jennifer,
You are absolutely correct about different transducers for Steel & Aluminum. We don't process any Aluminum. The step block is another issue. The Ultrasonic mic came with 2 step blocks, 1 is .500" & 1 is a 1.00". We have used both to set the ultrasonic for different thicknesses of steel over the last 3 years. When we started having problems the calibration source told us that we needed to buy a different transducer for use with the 1" step block.

Hopefully there are others here who have Ultrasonic micrometers who can provide some of their experience with them.