# Barley Malt as a Binder for Moulding Sands--Gas Evolution and Surface Quality of Iron Castings
## 3 Results and Discussion
### Macroscopic Examination of Castings  
Gray cast iron EN-GJL-200 was used to make the castings with EN-JIL1030 standards. The grade of cast iron selected by the foundry is used for castings that require good strength, tightness, and wear resistance. Gears, worm wheels of machines, cylinders, pistons, engine bodies, and guides are made of EN-GJL-200 cast iron. Two moulds were made for the experiment. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Sample**} & \multirow{2}{*}{\
\begin{tabular}{c} **Mass of Sample** \\ **[g]** \\ \end{tabular} } & \multirow{2}{*}{
\begin{tabular}{c} **Volume of Gases** \\ **[dm\({}^{3}\)/kg m.s.]** \\ \end{tabular} } & \multicolumn{4}{c}{**Emission of BTEX [mg/kg m.s.]**} \\ \cline{3-6}  & & **Benzene** & **Toluene** & **Ethylbenzene** & **Xylenes** \\ \hline D1 & 142.37 & 17.62 & 287.63 & 16.71 & 0.21 & 7.51 \\ \hline D2 & 134.03 & 17.97 & 254.47 & 14.18 & 0.23 & 7.20 \\ \hline Mean & 138.20 & 17.79 & 271.05 & 15.44 & 0.22 & 7.36 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Gas emissions from moulding sand (mg/kg moulding). \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Marking of a Moulding Sand Sample**} & \multirow{2}{*}{
\begin{tabular}{c} **Volume of Gases** \\ **[dm\({}^{3}\)/kg m.s.]** \\ \end{tabular} } & \multicolumn{4}{c}{**Gas Emissions [mg/kg.s]**} \\ \cline{3-6}  & & **Benzene** & **Toluene** & **Ethylbenzene** & **Xylenes** \\ \hline Oil & 112.100 & 2646.22 & 61.05 & 4.87 & 22.15 \\ \hline Green sand with lustrous carbon carrier & 19.11 & 386.73 & 9.76 & 0.13 & 1.19 \\ \hline Phenolic & 17.37 & 325.89 & 29.33 & 0.22 & 1.86 \\ \hline Alphaset technology & 11.303 & 246.7 & 2.1 & 0.3 & 0.02 \\ \hline Geopol (inorganic) & 9.90 & 37.00 & 0.58 & 0.01 & 0.00 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Comparison of emissions from moulding sands with various binders [10; 14; 15]. The moulds were poured horizontally. The poured moulds are shown in Figure 8, and the raw casting before knocking out the moulds is shown in Figure 9. After being knocked out, the castings were surface cleaned by sandblasting. Figure 10 shows the cleaned castings. Figure 8: View of the casting moulds after casting. Figure 9: View of the casting mould after opening but before knocking out. The results of roughness measurements of the produced castings are presented in Table 3 and Figure 11. During the measurements, the values of Ra and Rz were determined [16; 17]. The obtained results were compared with the values given in the table specifying the roughness of castings according to the casting methods. According to that classification, the obtained castings were classified as accurate sand casting and ordinary die casting (blue marking in Table 4). Figure 11: Surface profile of one of the two analysed castings. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Industrial Castings** & **Ra\({}_{\mathbf{av}}\)** & **R\({}_{\mathbf{zav}}\)** \\ \hline Average value from measurements & 12.33 & 54.12 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Results of roughness measurements of castings made in industry in moulds made of moulding sand with a binder of 2%. Figure 10: View of the casts: (**a**) No. 1; (**b**) No. 2. In order to compare the basic properties of the analysed sands, Table 5 shows a comparison of the research results of moulding sands with different binders. The analysed mass was presented first. The second and third moulding sands are sands commonly used in industry. The remaining masses are masses containing plant organic binders. Compared to the results of other moulding sands, the moulding sand with barley malt obtained the best results in terms of compressive strength and permeability. Other properties such as dry tensile strength, dry bending strength, dry wear resistance and flowability gave good results in comparison with the remaining compositions of the moulding sands.