# Comparison of Abrasive Wear Resistance of Hardox Steel and Hadfield Cast Steel
## 2 Materials and Methods
The differences in the chemical composition between samples 1 and 2 also resulted in a different level of hardness (sample 1-299 HBW, sample 2-256 HBW). The chemical composition of Hardox steels allows them to be classified as low-carbon (Hardox 450) and medium-carbon steels (Hardox 500, 600, Extreme). Increasing the amount of carbon lowers the austenite stability temperature, with a similar effect also exerted by non-carbide-forming elements, i.e., manganese, nickel and copper. The delay in diffusion transformation (the shift of the curves on the CTP diagram to the right) is the result of the use of both non-carbide- and carbide-forming elements, with manganese, molybdenum, chromium, silicon and nickel having the strongest effect on hardenability, respectively. The addition of boron in each of the analyzed steels occured in the maximum permissible concentration--0.002%. Larger amounts can cause coagulation of Fe\({}_{2}\)B compounds which favour nucleation of the ferritic phase. The content of nickel, also added to lower the temperature of the ductile-brittle transition, was highest for Hardox 600 steel (2.03%). Slight amounts of silicon, which are the residue of ferrosilicon, i.e., the compound used during the deoxidation process, showed an effect on improving hardenability. Trace amounts of titanium and aluminium could also be distinguished in all grades. Boron, having a strong affinity for oxygen and hydrogen, reacts with these elements to form boron nitrides or oxides. Titanium and aluminium additives bind the above gases into non-metallic phases, so that an adequate amount of boron remains dissolved in the matrix, guaranteeing the material's hardenability. In addition, these compounds, forming barriers to dislocation movement, slow down austenite grain growth. Vanadium micro additive can also have a similar effect. The amount of harmful admixtures (phosphorus and sulphur) is negligible, so that high strength and ductility indices are retained. For microscopic studies, a Nikon Eclipse MA200 light microscope (Nikon Corporation, Tokyo, Japan) was used. Samples were examined after etching with a 3% HNO\({}_{3}\) solution (Mi1 Fe). Nikon DS-Fi2 digital cameras, coupled to the microscopes, and Nikon's Photodocumentation NIS-Elements software (Nikon Corporation, Tokyo, Japan) were used to record and analyze images. Images of surfaces subjected to wear testing were taken with a Phenom XL electron microscope (Eindhoven, The Netherlands), using BSE imaging and a 15 keV accelerating voltage. Examinations of abrasive wear resistance were performed using a T-07 ribotester (Radom, Poland), with loose abrasive material acc. to GOST 23.208-79 [38], under constant load F = 44 N (\(\Delta\)F = 0.25 N). The T-07 tester was designed in the Institute for Sustainable \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline  & **Sample 1** & **ISO** & **Sample 2** & **PN-88/H-** & & & & **Hardox 450** & **Hardox 500** & **Hardox 600** & **Hardox Extreme** \\  & **GX120 MnCr17-2** & **13521:1999** & **L120G13T** & **83160** & & & & & **Hardox 500** & **Hardox Extreme** \\ \hline C & 1.23 & 1.20 & 1.10 & 1.00–1.40 & 0.17 & 0.29 & 0.44 & 0.45 \\ Mn & 18.00 & 17.50 & 12.50 & 12.00–14.00 & 1.00 & 0.74 & 0.53 & 1.00 \\ Si & 0.35 & 0.60 & 0.50 & 0.30–1.00 & 0.32 & 0.28 & 0.17 & 0.14 \\ P & 0.015 & - & 0.009 & \textless 0.100 & 0.010 & 0.007 & 0.006 & 0.006 \\ S & 0.009 & - & 0.008 & \textless 0.030 & 0.001 & 0.001 & 0.002 & 0.002 \\ Cr & 1.80 & 2.00 & 1.30 & \textless 1.00 & 0.45 & 0.61 & 0.31 & 0.07 \\ Ni & 0.35 & - & 0.50 & \textless 1.00 & 0.05 & 0.06 & 2.03 & 0.70 \\ Mo & - & - & - & - & 0.08 & 0.02 & 0.14 & 0.07 \\ B & - & - & - & - & 0.001 & 0.001 & 0.002 & 0.001 \\ Al & - & - & - & - & 0.032 & 0.054 & 0.039 & 0.040 \\ Ti & - & - & - & - & 0.016 & 0.003 & 0.006 & 0.003 \\ V & - & - & - & - & 0.005 & 0.012 & 0.006 & 0.008 \\ \hline hardness & 299 & 270–310 & 256 & 170–217 & 434 & 487 & 596 & 618 \\ \(\left[\text{HBW}\right]\) & & & & & & & & \\ \hline \hline \end{tabular}
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