침탄 처리 소재의 표면 분석을 위한 나노압입시험법의 응용

In the automobile and shipbuilding industries, various materials and components require superior sur face strength, excellent wear resistance and good resistance to repeated loads. To improve the surface proper ties of the materials, various surface heat treatment methods are used, which include carburizing, nitriding, and so on. Among them, carburizing treatment is widely used for structural steels containing carbon. The effective car burizing thickness required for materials depends on the service environment and the size of the components. In general, however, there is a limit in evaluation of the surface properties with a standardized mechanical test method because the thickness or cross-sectional area of the carburized layer is limited. In this regard, the nanoin dentation technique has lots of advantages, which can measure the mechanical properties of the material sur face at the nano and micro scale. It is possible to understand the relationship between the microstructural change in the hardened layer by carburizing treatment and the mechanical properties. To be spread to practical applica tions at the industrial level, in this paper, the principle of the nanoindentation method is described with a repre sentative application for analyzing the mechanical properties of the carburized materia