## 3 SB as SE Process--Review and Discussion  
### An Integrated Approach of SE Referred to SB  
At the core of SE is the idea of developing techniques/finishing processes to modify SL, and, thereby, improves the operational/functional behaviour of the components. This requires an integrated approach of studying the correlations between process (finishing), SI, and OB. This approach, applied to SB, is schematically presented in Figure 10.  
Figure 9: Percentage share of the methods of study.  
Figure 12 shows the relative share of the studied SI characteristics. The roughness estimated with the height parameter R\({}_{\text{a}}\)(S\({}_{\text{a}}\)) and the micro-hardness are most often the object of research, since their measurement requires rather affordable equipment and the least amount of time and resources. Half as much attention is given to the residual stresses, surface topography, and microstructure. Shape accuracy has only been investigated in [51]. Table 3 shows the methods used to determine the residual stresses. The experimental approach predominated (75%), whereas FEM was used in only six studies (21%). The preferred experimental method is X-ray diffraction (90%). The methods used to study the microstructure are shown in Table 4. The SEM analysis is used most often (55%), and the TEM analysis is used only in 6% of cases. This statistic is a consequence of the specifics of both types of electronic techniques. TEM analysis reveals information about the internal crystal structure of the studied material but requires high qualification to perform  
\begin{table}
\begin{tabular}{l l l} \hline
**Apex of the Triangle** & **Characteristic** & **References** \\ \hline
1. Physical nature of the & 1.1. Generated heat & [68, 69, 97] \\ SB process & 1.2. Study of the process thermo-mechanical nature & [68, 69] \\
1.3. Friction coefficient & [71] \\
1.4. Stressed state of the DB insert & [92] \\ \hline
2. SI of Shed surface & 2.1. Roughness R\({}_{\text{a}}\)(S\({}_{\text{a}}\)) & [37–39, 41, 42, 45–48, 54–57, 59–64, 66–68, 70, 72–79, 82, 84, 86, 88–90, 94, 94, 95, 98, 99] \\
2.2. Accuracy of the form & [51] \\
2.3. Surface stereometric structure (topography) & [36, 37, 40–43, 45–47, 50, 55, 60, 61, 75–79, 84, 90, 95] \\
2.4. Micro-hardness & [36, 37, 40–42, 44, 47, 49, 95, 53, 58–60, 64, 66, 88–28, 81, 84, 86, 87, 89, 90, 93, 95–99] \\
2.5. Residual stresses & [36, 37, 46, 47, 53, 57, 60, 61, 67, 69, 71–76, 84, 87, 91, 95, 96, 99] \\
2.6. Microstructure & [36, 40–43, 47, 65, 67, 68, 72–76, 79, 81, 83, 93, 94] \\ \hline
3. Operating behaviour of & 3.1. Wear resistance & [36, 40, 42–44, 77, 79] \\ the slide burnished surface & 3.2. Corrosion resistance & [90, 93] \\
3.3. Fatigue behaviour & [37, 45, 47, 67–70, 72–75, 81, 96] \\
3.4. Deniding properties & [90] \\ \hline \end{tabular}
\end{table}
Table 2: Classification of the investigations on SB by criterion apex of the triangle ‘SB–SI–OB’.  
Figure 10: Schematic presentation of the correlation ‘SB–SI–OB’.  
Regarding the OB of the Sbed surface, the effect of SB on the fatigue behaviour (57%) was most often studied, followed by the wear resistance (30%), corrosion resistance (9%), and bending properties (4%). This statistic confirms the potential of SB to be used as a hardening or mixed burnishing process.