Improvement of the wear resistance of cold work tool steel wire drawing jaws using the thermochemical bording method

In this study, the boridability of cold work tool steel wire drawing jaws was investigated by thermochemical boriding method. The aim of the research is to increase the lifespan of wire drawing jaws, which wear out and become unusable in a short time, by improving the surface hardness and wear resistance properties by boriding. For this purpose, wire drawing jaw samples were boronized at different temperatures (900 °C, 950 °C and 1000 °C) for 6 hours. It was prepared metallographically to examine the coating sections of the borided samples. Microstructural examinations of the obtained coating layers, coating layer thicknesses, elemental distribution and phase structure of the coatings were determined by optical microscope, scanning electron microscope (SEM), energy dispersion spectrometry (EDS), and X-Ray Diffraction (XRD). Microhardness and wear tests were applied to determine microhardness, fracture toughness and wear resistance values. As a result, it was observed that a homogeneous two-layer coating layer consisting of FeB and Fe2B was obtained. It has been observed that coating thicknesses increase with increasing coating temperatures. In addition, thicker coatings were obtained on the gear surfaces of the samples compared to the flat surfaces. It was determined that the microhardness of the coatings was 5-6 times higher than the substrate material. Although the fracture toughness values increased slightly with increasing coating temperature, no significant difference was observed. As a result of the wear tests, it was observed that the wear rates decreased approximately 4 times in the coated samples.