# Comparison of Abrasive Wear Resistance of Hardox Steel and Hadfield Cast Steel
## 2 Materials and Methods  
For abrasive wear testing of Hardox steel, 10-mm-thick steel sheets provided by the authorized distributor, STAL-HURT company, were used. On the other hand, samples for testing abrasive wear of Hadfield steel in the post-operational condition were taken from the following assemblies of mine machinery and equipment structures:  
* material of the jaw crusher (Sample 1)
* ball mill liner plate material (Sample 2). The above components come from one of the melaphyre mines located in Lower Silesia (Poland). Melaphyre belongs to magmatic rocks formed during the Palaeozoic period. In terms of quality, it corresponds to tertiary basalts and is a raw material for the production of various types of aggregates. These aggregates are produced in fractions from 2 to 63 mm. Their applications are very wide and apply to wearing layers, binders and substructures in road construction, aggregates for concrete, as well as aggregates for railroad ballast. After mining, melaphyre is crumbled using crushers, with the fastest consumable elements being their jaws. It is then ground into various fractions in ball mills (the critical elements are the liner plates). Subsequently, the excavated material is deposited in stockpiles through a system of conveyor belts and transfers (the critical elements of the transfers are the liner plates as well). Figures 1 and 2 show macroscopic photos of the tested components in their post-operational state. As can be seen from the photographic documentation, the wear on the working surfaces of samples 1 and 2 consists of abrasion of their surfaces and a change in geometry--in the case of the jaw crusher, a reduction in the height of the protrusions on the working surface, and in the case of the ball mill liner plate, a fairly uniform ploughing. In both cases, no cracks of a macroscopic nature were found on the surfaces of these samples. While the changes in the condition of the working surface of the jaw crusher indicate the loss of the assumed properties, the condition of the surface of sample 2 suggests the possibility of the continued operation of the liner plate. The hardness was measured using a Zwick/Roel ZHU 187.5 universal hardness tester (Zwick Roell Gruppe, Ulm, Germany) using the Brinell method, in accordance with PN-EN ISO 6506-1:2014-12 [35]. A carbide ball with a diameter of 2.5 mm was used, with a load of 187.5 kgf (1838.7469 N) applied for 15 s.  
Analyses of chemical composition were carried out using the spectral method via a Leco GDS500A glow discharge emission analyser (LECO Corporation, St. Joseph, MI, USA). During the analyses, the following parameters were used to allow ionization of the inert gas: U = 1250 V, I = 45 mA, 99.999% argon. The obtained results were the arithmetic average of at least five measurements. The results of chemical analyses of samples 1 and 2 confirm that the post-operational samples represent high-manganese cast steels (Table 1). The chemical composition of sample 2 met the requirements of PN-88/H-83160 standard [36], showing an overestimated (by 0.3%) content of chromium, which stabilizes the microstructure by blocking the separation of manganese cementite and increases wear resistance due to the presence of carbides. In  
Figure 1: Sample 1. Macroscopic image of the condition of the working surface of the jaw crusher for squashing rocks with a volume of 10–1000 mm. Operating time of about 350 h, throughput of about 80.00 tons. Figure 2: Sample 2. Macroscopic image of the surface condition of the ball mill liner plate covering part of the contracture of the chute. Material volume of 100–1200 mm, throughput of about 200.000 tons. sample 1, the manganese content (at 18%) was significantly higher than in in the case of sample number 2, while the chromium content was 1.8%. The established chemical composition of this material allows it to be classified as steel grade GX120 MnCr 17-2, captured in the ISO 13521:1999 [37] standard.