PSI - Issue 36

Pavlo Prysyazhnyuk et al. / Procedia Structural Integrity 36 (2022) 130–136 Pavlo Prysyazhnyuk et al. / Structural Integrity Procedia 00 (2021) 000 – 000

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Studies of the worn surfaces after impact-wear tests using SEM (Fig. 5) show, that its wear morphology significantly differs, indicating different dominant wear mechanisms. The surface of the sample with EMH hardfacing (Fig. 5a) is covered with shallow grooves, resulting of abrasive particles micro-ploughing action, occurring after the direct impact penetration. Carbide particles remain fixed in austenitic matrix, preventing surface from micro-cutting action by sharp edges of abrasive particles. So, in the given case the wear proceeds mainly by formation of relatively small fatigue craters, as a result of cyclic impact loads with further rolling of abrasive particles. On the worn surface of a sample, deposited with a commercial ESAB OK 13MN electrodes, most defects are caused by delamination of deformed layers, leading to the formation of relatively deep craters (Fig. 5b). The presence of scratches, resulting from micro-cutting abrasive particles action was also observed at the surface. The worn surface of HSS sample (Fig. 5c) has traces of brittle fracture, represented by microcracks in form of the discrete local networks causing the occurrence of surface chipping. Due to high surface hardness of HSS with respect to other tested materials, wear traces such as scars, scratches, grooves etc., were not observed. The wear of the St. 45 at given conditions accompanied by severe surface damage associated with developing of catastrophic wear (Fig. 5d). The surface morphology consisted of wide regions with deep caverns and craters producing high volumes of wear debris. 4. Conclusion The impact-wear resistance of surfaces, deposited with experimental and commercial high-manganese steel-based hardfacing materials as well as high speed steel and mild carbon steel has been investigated. According to obtained experimental results it can be concluded, that alloying of high-manganese steel-based hardfacing FCAW material with refractory carbides of Ti, Nb, Mo and V in equimolar ratio, allows to increase its impact-wear resistance up to 3 times, which is almost equal to impact-wear resistance of high-speed steel samples tested under the same conditions. Such an improvement in properties was attributed to the formation of single complex carbide phase of cubic crystal system (T, Nb, Mo, V)C during FCAW hardfacing process. This phase precipitates at high temperature and characterized by multicore/rim structure, so after the ending of solidification process the hardfaced layer consists of manganese austenite matrix comprising (Ti, Nb, Mo, V)C carbide inclusions in form of uniformly distributed faceted grains with an average size about 2 µm and total volume content of approximately 12%. The hardness of such hardfaced layer can be increased from 46 to 57 HRC by work-hardening under impact conditions. Therefore, FCAW hardfacing with electrode materials of a high-manganese – complex (Ti, Nb, Mo, V) carbide system can be suggested for recovering and hardening the wear parts of mining, milling, earth-moving and similar equipment. References Ayadi, S., Hadji, A., 2020. Effect of chemical composition and heat treatments on the microstructure and wear behavior of manganese steel. International Journal of Metalcasting 15(2), 510 – 519. doi:10.1007/s40962-020-00479-2 Bayhan, Y., 2006. Reduction of wear via hardfacing of chisel ploughshare. Tribology International 39(6), 570 – 574. doi:10.1016/j.triboint.2005.06.005 Bazaluk, O., Velychkovych, A., Ropyak, L., Pashechko, M., Pryhorovska, T., Lozynskyi, V., 2021. Influence of heavy weight drill pipe material and drill bit manufacturing errors on stress state of steel blades. 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