Overcoming Plate Lamination Defects with Ultrasonic Testing – UT
Lamination in metal plates is a serious defect that can compromise performance and strength. By far the best way to check for this is using ultrasonic testing (UT).
It’s one of the easiest forms of NDT, whereby a probe or transducer is used to pass sound waves through the plate. It provides immediate results, can be done on a single side of the plate, and registers defects at surface level and deeper.
Metal plates are made by running the metal through a series of rollers. This is either a hot or cold process. But the result of either is to gradually reduce the plate to the desired thickness. However, any tiny flaw within the metal can elongate during the process, causing lamination that follows the direction of the rollers. Another common anomaly is caused when layers of metal are compressed together to create the plate. While this is effective, the process doesn’t cause the metals to bond, so they can separate with use.
The UT inspection process is simple. A sound metal plate won’t return any abnormality to the sound waves. But a defect will cause the wave to bounce away. This allows a 3D visualisation to be formed that shows where in the plate the defect/s is located.
Loss of Strength and Integrity
Lamination can occur anywhere in the plate – within the body, on a surface or at the edge. Wherever it’s located, such a flaw significantly reduces the strength of the plate. In the worst-case scenario, this also impairs the loading performance, even causing the plate to buckle or fail completely.
Edge defects pose additional issues. The loss of integrity can compromise any connections – such as welds.
This highlights the importance of regular testing and UT is by far the premier way to do this. This mainstay of NDT is relatively inexpensive and can reduce the risk of far more costly outcomes that come from using a plate with lamination defects.
Ultrasonic testing, also known as ultrasonic thickness measurement (UTM), sonic testing (ST) and ultrasonic thickness testing (UTT) is just one of the non-destructive testing methods that Nexxis provide advanced equipment for. With a wide selection of UT testers available off the shelf, we also specialise in curating bespoke testing options to suit even the most challenging of scenarios.
Check out The Benefits of Ultrasonic Testing for Composite Structures to find out more!