# The Predictive Model of Surface Texture Generated by Abrasive Water Jet for Austenitic Steels
## 3 Results and Discussion
### Interpretation of Obtained Results and Design of Using them for the Application Sphere
Based on the verification of the prediction model (10), for all four categories, the following can be recommended:  
* For a material thickness of 0.1-5 mm, the roughness of 1-6.3 \(\upmu\)m is guaranteed, abrasive 130 g-min\({}^{-1}\),
* For a material thickness of 5-20 mm, the roughness of 3.2-12.5 \(\upmu\)m is guaranteed, abrasive 180 g-min\({}^{-1}\),
* For a material thickness of 21-50 mm, the roughness of 6.3-25 \(\upmu\)m is guaranteed, abrasive 250 g-min\({}^{-1}\),
* For a material thickness of 51-80 mm, the roughness of 12.5-40 \(\upmu\)m is guaranteed, abrasive 300 g-min\({}^{-1}\) (usually without roughness guarantee for cutting with an allowance),
* For a material thickness of over 80 mm, cutting with an allowance, abrasive 350 g-min\({}^{-1}\). The optimal set of factors were identified from a physical, technological, and technical point of view in relation to the quality and productivity of the hydro-abrasive erosion process. The impact of technical factors on the hydro-abrasive manufacturing process largely affects the continuity of the manufacturing process, so the whole complex of these factors can significantly affect the overall productivity of the manufacturing process. The decisive factors are water specification, hydraulic and high-pressure systems, as well as the choice of water and abrasive nozzles. The publication also provides specific recommendations for practice based on the specific requirements of customers from practice based on the achieved results according to the prediction model (10):  
**1. Recommendations for a group of materials of austenitic steels 30 mm thick:**  
* For a thickness of 0.1-5 mm, a roughness of 1-3.2 \(\upmu\)m, a speed of 250-800 mm-min\({}^{-1}\) is guaranteed,
* For a thickness of 5-10 mm, a roughness of 3.2-12.5 \(\upmu\)m, a speed of 110-250 mm-min\({}^{-1}\) is guaranteed,
* For a thickness of 10-20 mm, a roughness of 6.3-12.5 \(\upmu\)m, a speed of 70-110 mm-min\({}^{-1}\) is guaranteed,
* For a thickness of 20-30 mm, a roughness of 6.3-15 \(\upmu\)m, a speed of 25-70 mm-min\({}^{-1}\) is guaranteed. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Water Nozzles** & **Focusing Nozzles Recommended by the Manufacturer** & **Focusing Nozzles Designed and Verified in WATTING Preslov** \\
**[mm]** & **[mm]** & **[mm]** \\ \hline
0.20 & 0.76 & 0.76 or 1.02 \\
0.25 & 0.76 or 0.80 & 0.76 or 1.02 \\
0.30 & 0.90 & 0.76 or 1.02 \\
0.35 & 1.10 & 0.76 or 1.02 \\ \hline \hline \end{tabular}
\end{table} 
Table 12: Standard and proposed nozzle (jet) configurations. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Water Nozzles** & **Focusing Nozzles Recommended by the Manufacturer** & **Focusing Nozzles Designed and Verified in WATTING Preslov** \\
**[mm]** & **[mm]** & **[mm]** \\ \hline
0.20 & 0.76 & 0.76 or 1.02 \\
0.25 & 0.76 or 0.80 & 0.76 or 1.02 \\
0.30 & 0.90 & 0.76 or 1.02 \\
0.35 & 1.10 & 0.76 or 1.02 \\ \hline \hline \end{tabular}
\end{table} 
Table 13: Sizing variants for splitting water jet. Recommendation of constant parameters for the following stated material thicknesses:  
* Water flow 0.25 mm,
* Abrasive weight max. 200 g\(\cdot\)min\({}^{-1}\),
* Abrasive nozzle 0.76 mm,
* Water pressure 300 MPa.