What To Know About Eddy Current Testing
Eddy current testing is a way for those who work with specialty metals to test for imperfections, such as cracks or gaps. These flaws are detected by electromagnetic induction. It can catch these flaws on the surface of the material, but also in the sub-surface. Not only that, but eddy current testing can also be used to measure the conductivity and thickness of a material. Here are some things that you might find interesting about eddy current testing.
Nondestructive Testing (NDT)
Eddy current testing is categorized as a nondestructive testing method. This means two things. For one, the system is reliable, safe, and cost-efficient. The other is that the testing is conducted without causing harm to the material or any parts connected to it. It will also do nothing to affect the use of them in the future. There are several NDT techniques, including simply using the eyeball test, and eddy current testing is one of the most important.
It is Vital in Everyday Life
It may surprise you to hear that eddy current testing is an important part of our lives, but it is absolutely true. Eddy current testing is used in many industries and for many of the products we interact with daily. As an example, eddy current testing is the preferred method to use for testing oil and gas pipelines, chemical manufacturing, nuclear reactors, and our local water systems. There is portable equipment for eddy current testing to perform inspections on site, such as on bridges. Public safety is greatly enhanced by using eddy current testing, which makes it important to us. Not only can it be used for those large components, but it can also be used for smaller parts that also have an impact on safety.
Different Probes Depending on the Mode
ECT uses test probes that come in several styles and sizes. They do not just have different shapes, but also have varying modes of operation. Take, for example, an absolute measurement probe. This probe creates eddy currents by using a coil. These currents then track any changes in the current field. Another probe has two coils, so that the operator can use comparisons to find flaws. If there is a coil lingering over an imperfection, and the other is over a good spot, then the operator gets a signal.
There are Several Factors That Can Affect Eddy Current Testing
Eddy current testing equipment generally comes with several settings. There is amplitude, frequency, and sensitivity, among others. These all need to be considered when performing ECT. That said, there are other factors in play as well. You must consider anything that might affect the flow of the currents, such as any properties of the material you are testing. If there are obstructions, then an adjustment to the settings may be required.
Magnetic permeability is one of those factors that can affect how easily the currents flow through a material. When measuring permeability, there can be interference created when using ferrous materials. That makes it hard to use eddy current testing for accurate results. To get over this, technicians can use magnetic saturation or different coil arrangements to get accurate readings.
When it comes to interference, even ambient room noise can cause problems for eddy current testing. The best option is to try to filter out any noise in the environment to get a good signal. There can also be issues if the part or material being tested has sharp or geometrical edges. Technicians can use a special scanning technique to overcome this.
The eddy current testing procedure is used on several materials, such as tungsten and molybdenum rods. It is an effective way to inspect materials for damage, cracking, fractures, and pitting.
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