## 3 Analysis of Experimental Results  
### Analysis of Grinding Surface Quality  
Grinding is often used for material removal, eliminating excess weld height, or polishing, which also makes the weld surface smoother. The surface of the grinding workpiece is observed by an optical microscope at 50\(\times\) magnification. We obtained an observation graph, as shown in Figure 6A,A', respectively, which show the micrographs of the weld surface and the weld ridge before grinding. By comparing the micrographs before and after grinding, it can be seen from the figure that the surface texture before grinding is relatively messy with obvious texture fracture, while the surface texture after grinding is uniform and continuous. Figure 6 (a)-(d), (a')-(d') represents the surface machined under the grinding parameters in Table 3. Under different parameter conditions, the surface after grinding is different, but compared with the surface without grinding, it is relatively smooth, and the consistency of surface texture is very good. It can be seen that the diamond belt grinding can eliminate well the welding margin of titanium alloy electron beam welds so that the welding margin meets the requirements of parts and achieves a smooth transition between the machined surface and the substrate.  
In this experiment, the roughness instrument TR200 was used to measure the roughness parameter Ra. The surface roughness of the welded surface under the grinding parameters in Table 3 is measured, as shown in Figure 7.  
From the results of the roughness measurement, it can be seen that the roughness decreased after grinding with the decrease in feed speed. With the increase of belt speed, the roughness decreased after grinding. The surface roughness of the welded face was generally lower than that of the welded ridge, which shows better grinding machinability.  
Due to the larger width of the welding surface, grinding can reduce the surface roughness of the workpiece and improve the surface finish. Therefore, the face of EBW should be the main working face of the workpiece, while the ridge of welding should be the secondary working face or non-working face of the workpiece. Similarly, the belt grinding of titanium alloy EBW seam follows the basic rule of material removal. With an increase in cutting speed and decrease in feed speed, the surface quality and roughness improve. Therefore, when choosing the grinding speed of the belt, we should try to choose a faster belt speed and lower feed speed when considering the factor of roughness.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Project** & **Parameter** \\ \hline Belt width & & 5 mm \\ Particle size & & P200 \\ Feed mode & & Longitudinal \\ Cooling mode & & Air cooling \\ Contact wheel & & Natural rubber \\ \hline \hline \end{tabular}
\end{table}
Table 2: Grinding parameters.  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**The Experimental Group** & **(a) and (a’)** & **(b) and (b’)** & **(c) and (c’)** & **(d) and (d’)** \\ \hline Belt speed v\({}_{\text{s}}\)(m/s) & 10 & 15 & 15 & 15 \\ Feed rate v\({}_{\text{p}}\) (m/s) & 0.010 & 0.010 & 0.015 & 0.015 \\ Grinding positive pressure & & 10 & 10 & 10 & 15 \\ F\({}_{\text{n}}\) (N) & & & & & \\ \hline \hline \end{tabular}
\end{table}
Table 3: Experimental parameters.  
Figure 6: Surface of welded seam after grinding as seen through an optical microscope.