Conference Agenda

This study investigates the effects of cold plastic deformation at room temperature using a Bridgman anvil, in combination with different heat treatment conditions, on the hardness, wear resistance, and microstructure of X160CrMoV12 cold work tool steel. The samples were divided into three groups: Batch I (As-Hardened), Batch II (Hardened and Tempered), and Batch III (Hardened and Plastically Deformed), with hardening performed at 1100°C, 1150°C, and 1200°C. Batch I served as the baseline, where the samples were hardened without tempering or deformation. The results showed that the retained austenite content was highest at 1200°C (69.02%) and lowest at 1100°C (17.36%), with the latter promoting a more martensitic structure and higher hardness. In Batch II, after tempering at 600°C for 1.5 hours, the retained austenite content significantly decreased, with a corresponding reduction in hardness but improved toughness. Batch III explored the effect of cold plastic deformation. After hardening, the samples were plastically deformed, leading to a significant increase in surface hardness, with a hardened depth of about 0.08 mm. The plastically deformed samples showed superior wear resistance compared to both the hardened-only and tempered samples. Notably, the best wear resistance was achieved in samples hardened at 1100°C, which showed the lowest retained austenite and a stable martensitic structure. X-ray diffraction (XRD) and scanning electron microscopy (SEM) revealed the microstructural changes. The XRD results confirmed higher levels of retained austenite at higher hardening temperatures, while SEM images showed finer microstructures in the plastically deformed samples, contributing to improved wear performance. In conclusion, cold plastic deformation significantly enhanced surface hardness and wear resistance, especially when combined with lower hardening temperatures. The optimal hardening temperature for maximum wear resistance was 1100°C, while tempering reduced retained austenite but also decreased hardness. This study suggests that cold plastic deformation is a promising method for improving the wear resistance of cold work tool steels, offering a cost-effective alternative to additional heat treatments. In summary, plastic deformation after conventional hardening increases the hardness and refines the microstructure of cold work tool steel, resulting in slight increase of wear resistance comparing with as-hardened samples. This highlights the importance of combining heat and mechanical treatments to achieve better properties of cold work tool steels.

The aim is to overcome the issues of high-hardness material welding by different additives used to achieve the desired improvements. The research is focused on Hardox 450 steel welding and factors to be considered in order to maintain the required mechanical properties of the weld. The selection of best suited welding materials or additives, including filler metals and shielding gases, are within the important factors to be taken into account. During the welding of Hardox 450 steel, cobalt, nickel, tungsten and titanium additives and cobalt and tungsten mixture additives were used and their influence on the microstructure and mechanical properties of the fusion and heat-affected zones was investigated. The microstructure of the weld zone is related to certain mechanical properties of the weld and heat-affected zone, such as hardness, tensile and bending strength, yield strength, strain at ultimate tensile strength, the Young’s modulus and elongation. Research has shown significant differences in the mentioned parameters depending on specific additives used in the welds. It can be concluded that tungsten, used as an additive, increased the hardness of the heat-affected and fusion zones up to 478 HV; the combined presence of cobalt and tungsten additives improves the strength of the seam up to 744 MPa during tensile; and in the case of bending, nickel, when used as an additive, increased ductility (the bending modulus reached the limit of 94 GPa) and at the same time, decreased the risk of cracking. The obtained results highlight the possibilities for strengthening the welded joint of Hardox 450 steel using different additives or their mixtures. The research conclusions and recommendations aim at improving the quality and mechanical properties of welded Hardox 450 steel joints in various applications.