## 5 Results
### Analysis of Rope in the Second Quality Class  
Table 4 shows that the majority of wire strength values fall outside the nominal accuracy range, specifically outside the interval \(\langle 1770;\ 1911.6\rangle\) MPa. The target accuracy value for the second quality accuracy class is 1759 MPa. The highest variation range (V\({}_{\text{x}}\) = 152.87) is observed for Wire No. 2, which also exhibits the highest standard deviation (s = 42.07). The corresponding variance (s\({}^{2}\) = 1769.66) confirms notable variability in wire strength. \begin{table}
\begin{tabular}{c c c c c} \hline \hline  & **Wire 1** & **Wire 2** & **Wire 3** & **Wire 4** \\ \hline Arithmetic mean [MPa] & 1725.84 & 1782.17 & 1769.84 & 1804.67 \\ Maximum value [MPa] & 1754.35 & 1847.13 & 1791.40 & 1831.21 \\ Minimum value [MPa] & 1692.64 & 1694.27 & 1691.88 & 1771.50 \\ Variation range (V\({}_{\text{x}}\)) [MPa] & 61.71 & 152.87 & 99.52 & 59.71 \\ Standard deviation (s) [MPa] & 14.73 & 42.07 & 23.49 & 24.11 \\ Variance (s\({}^{2}\)) [MPa] & 217.00 & 1769.66 & 551.83 & 581.07 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Statistical analysis of the strength of four wires from second-quality-class rope. Figure 9: Process capability indices for a third-quality-class rope (3 wires). Similarly, Wire No. 3 presents a higher variation range (V\({}_{\rm x}\) = 99.52) and a standard deviation of 23.49, further indicating inconsistency in mechanical properties. A higher accuracy dispersion value indicates significant differences in the measured accuracy values of the respective wires. From the perspective of tensile performance, these values highlight the characteristic strength behavior of wires used in steel ropes of the second quality class (construction type: 22.4 6x27 NS SFC 1570 U sZ. The histogram presented in Figure 10 clearly confirms a deviation from normal distribution, as indicated by its irregular shape. Most of the observed values lie within the interval \(\left<1745;\ 1755\right>,\) which is significantly below the acceptable range. Furthermore, the target strength value of 1759 MPa falls outside the specified tolerance limits (Lower Specification Limit--LSL = 1770 MPa; Upper Specification Limit--USL = 1911.6 MPa), confirming that the measured tensile strengths are generally insufficient. This deficiency in wire strength directly impacts the overall quality and performance of the steel rope. Additionally, the majority of the strength measurements are below both the LSL and the target value, as shown in Figure 10. The uneven distribution of data, particularly in intervals below the LSL, further supports the conclusion of inadequate process control and non-compliance with the specified quality requirements. Figure 11 illustrates that the measured tensile strength values of the wires fall outside the nominal accuracy interval of \(\left<1770;\ 1911.6\right>\) MPa. Given that the assumption of normal distribution is not satisfied, the application of capability indices (e.g., C\({}_{\rm p},C_{\rm pk}\)) is not justified and may lead to misleading conclusions. Based on the findings from Figures 10 and 11, it can be concluded that the process lacks both stability and capability. The distribution of the measured strength values clearly reveals a deficiency in wire strength, further reinforcing concerns about the quality and reliability of the steel rope in the second quality group. Figure 11 reveals that wires No. 1, No. 2, and No. 3 exhibit minimum tensile strength values below the nominal threshold of 1770 MPa. Given that the manufacturer specifies a nominal accuracy interval of \(\left<1770;\ 1911.6\right>\) MPa, the measured values fall outside the defined specification limits. Figure 10: Histogram and capability analysis of wire strength in a second-quality-class rope (4 wires). As a result, due to the substandard values below the lower specification limit (LSL = 1770 MPa), it can be concluded that the customer's requirements for wire strength are not fulfilled.