Measuring the nodularity of cast iron is possible by measuring the ultrasonic sound velocity in the material. The grade of nodularity of cast iron can be indirectly determined by measuring the ultrasonic sound velocity of the casted product.
Nodularity is proportional with the sound velocity of the cast iron, which means that by measuring the propogation speed of sound in the casted product itis possible to determine the nodularity level.
What do you need ?
Determination of the sound velocity can be done manually with a simple ultrasonic gauge and a mechanical caliper.
With a mechanical caliper the thickness is measured and at the same spot the ultrasonic time of flight is measured by simply placing a transducer ( probe) on the material using a little coupling fluid.
The ultrasonic gauge measures the time which is needed for a short ultrasonic puls to travel through the product, bounce bach at the rear side and received back into the pobe . Same like a typical sonar system. The materials sound velocity V can then be calculated . V = thickness/ time of flight in meter/second or inches/second
Inspection Technology Europe BV has developed a practical tool to carry out this measurement quick, with minimum effort and accurate. The systems grip contains a caliper which mechanically measures the thickness of the product and with an automatic water supply system the ultrasonic probe in the tip of the caliper is acoutically coupled.
Ultrasonic coupling can also be done with conventional couplant gel without using water supply.
ultrasonic measurement of nodularity
The result shows the sound velocity which is immediately visible on a display and the user can set the alarm limits for accept / not accept measurements and optionally store the data in a database.