How can temperature variations affect Eddy Current Testing?

Temperature variations can significantly influence the conductivity and permeability of materials, which are critical factors in Eddy Current Testing (ECT). As temperature increases or decreases, the electrical resistivity of the material can change, leading to altered eddy current flow. In conductive materials, such as metals, an increase in temperature typically results in higher resistivity and lower eddy current intensity, which can affect the depth of penetration and the amplitude of the signals received during testing.

Similarly, the magnetic permeability of ferromagnetic materials is also temperature-dependent, particularly near their Curie temperature, where they can change from a ferromagnetic state to a paramagnetic state. When these properties change due to temperature fluctuations, the ability of the Eddy Current Testing method to accurately detect flaws or assess material properties can be compromised. Therefore, understanding and controlling temperature conditions are crucial for obtaining reliable and valid test results in ECT.