# Comparison of Abrasive Wear Resistance of Hardox Steel and Hadfield Cast Steel
## 4 Discussion  
This paper presents the results of abrasive wear testing of Hardox steel and Hadfield cast steel, which was taken from equipment components used in the mining industry. According to the presented results, the abrasive wear of high-manganese steel is comparable with the resistance of Hardox 600 steel. In martensitic steels, the relationship of hardness and abrasive wear resistance shows a linear correlation. The comparable resistance of steels with a hardness not exceeding 450 HBW and C45 steel in the as-normalized condition (hardness of 220 HBW) is determined by the wear mechanism. C45 steel is composed of 50% ferrite, which undergoes plastic deformation, and the increase in resistance is only pronounced for steel with a hardness of 500 HBW, as it was already noted in the [43]. Also, according to the results presented in [44; 45], steel with ferritic-peariltic-bainitic microstructure may show an advantage over martensitic steel. In this case, the main wear mechanism is microploughing, and mass loss occurs only as a result of repeated plastic deformation of the material and thus its mechanical strengthening. Microloughing alone--unlike microcutting--does not result in mass loss, and caution should be exercised within ferrite-containing steels when evaluating abrasive wear resistance as a function of mass loss. However, it is not always the case, and Hardox 450 steel is considered more advantageous in terms of abrasive wear resistance in comparison to S355]2G3 steel [34]. The obtained correlation between hardness and abrasive wear resistance is consistent with the results presented in [46]. In the aforementioned work, [PERSON] studied eight steels with carbon contents in the range of 0.31-0.41 wt%, which were characterized by different content of manganese, chromium, vanadium, as well as boron. All the materials were hardened to a martensite microstructure, and in this state their wear intensity was related to carbon content and hardness, and, in the course of later studies, to yield strength [47]. In the paper [48], five commercially available martensitic steels with hardnesses of 400, 500 (three types) and 600 HBW were tested. Each of the used test methods (crushing pin-on-disc, high-speed slurry-pot and impeller-tumbler device) conditioned the generation of high stresses that led to the crushing of the abrasive, plastic deformation of the tested surface and the formation of adiabatic shear bands inside the material. Nevertheless, in each case, the steel with a hardness of 400 HBW showed the least favourable wear rates, while the steel with a hardness of 600 HBW exhibited the lowest mass consumption. In the work [33], the material with the highest hardness of 49.9 HRC (the steel used for polyughshares by Lemken) also showed the most advantageous wear resistance, both in laboratory and field tests. However, in the work presented here, within the martensitic microstructures, the relationship between hardness and abrasive wear resistance was not observed. Hardox 500 steel (hardness of 47.1 HRC) showed higher wear rates compared to B27 steel (hardened state with a hardness of 45.7 HRC and low-tempered state with a hardness of 44.2 HRC), which was associated with a change in the nature of wear. The problem of uneven behaviour of different steels with a hardness of 400 HBW, which is caused by the strengthening of subsurface layers due to plastic deformation, is also pointed out by the authors of the paper [49; 50; 51]. Nevertheless, in the above cases, the variation in hardness between the analyzed grades does not exceed 50 Brinell units, and clarification of these relationships requires further research related to the correlation of microstructural and mechanical properties with chemical composition. It should be noted that the relationship of hardness and wear resistance within martensitic steels seems reasonable only for loose (dry) abrasive (Figure 8).