Selected NDT Techniques in Heat Treatment Control

Abstract

The article deals with the control possibilities of chemical heat treatment of two types the most frequently used steels using common non-destructive testing techniques of materials. Nitriding and cementation processes were chosen as chemical heat treatment. The properties and thus the quality of the layers formed by this chemical heat treatment were determined using the eddy current method, ultrasonic technique and also the acoustic emission technique. These selected techniques are frequently used to flaws detection, which also arise in chemical heat treatment processes. As the thickness and properties of the surface layers significantly affect the electrical and acoustic properties of the substrate material, these techniques can also be used to control the performance of chemical heat treatment without the need to engage in destructive metallographic techniques. From the analyzes, the possibility of verifying the quality of chemical heat treatment using NDT techniques was confirmed. This could in the future lead to the possibility of including some NDT techniques in the process of material output control, both in the case of piece and serial production.