## 3 Results and Discussion
### Mixing Behavior in Laser Cold-Wire Test Welds  
Figure 15 shows EDS mapping results for the laser cold-wire test welds. The images in Figure 15 show chromium distribution in weight-% for each test weld cross-section. Figure 16 presents tabular data for average values of filler metal mixing determined at the measurement lines ML1-ML4 of the laser cold-wire test welds. Examination of Figure 15a-e shows a clear difference in filler metal  
Figure 14: Filler metal mixing results from EDS stepwise characterization. (**a–d**) Filler metal mixing-% profiles of measurement lines 1–4 (ML1–ML4) from test weld LAH6 (**e**). In figures (**a–d**) one step between adjacent measurement points in the horizontal axis equals 100 micrometres. Figure 13: Filler metal mixing results from EDS stepwise characterization. (**a–d**) Filler metal mixing-% profiles of measurement lines 1–4 (ML1–ML4) from test weld LAH5 (**e**). In figures (**a–d**) one step between adjacent measurement points in the horizontal axis equals 100 micrometres. mixing between the weld surface part (upper half) and the weld root part (lower half) of the weld cross-sections when the root gap of the I-groove was closed or 0.4 mm. In Figure 16, average filler metal mixing values in test welds LCW3 and LCW4 are around \(\sim\)32-36% in the lower half of the weld cross-sections (ML3-ML4), whereas the level in the upper half of the weld is much higher, \(\sim\)48-54%. The same mixing behaviour can be seen for both leading and trailing filler wire feeding. Comparison of the EDS-mapping images of welds LCW3 and LCW4 in Figure 15c,d indicates that slightly more intensive mixing occurred in the lower half of the joint in weld LCW3, which was produced with leading wire feeding. Figure 15: EDS mapping images (**a**–**h**) showing the distribution of chromium in laser cold-wire test welds. When the root gap was widened to 0.8 mm, leading wire feeding still has a clear difference in mixing between the upper and lower half of the weld cross-section, Figure 15e. However, the results of trailing wire feeding with 0.8 mm root gap show enhanced mixing behaviour across the whole weld cross-section in terms of higher chromium weight-% and more homogenous distribution, Figure 15f. Figure 16 shows average filler metal mixing values between 39% and 42% for test weld LCW6 at measurement lines ML3 and ML4. In addition, Figure 17d, which presents the mixing profile for the weld root portion, shows homogenous mixing at the bottom of the groove. In the closed square butt weld with zero root gap, the filler metal mixing behaviour was remarkably inhomogeneous. In Figure 15a,b, distinctive colour contrast can be seen between high chromium and low chromium weight-% areas. Figure 18 shows mixing profiles derived from the EDS-line scans and micrographs taken at the same locations (Figure 18a). Local inhomogeneous mixing is clearly visible in the EDS chromium mapping image of the zero root gap test weld LCW1. Mixing profiles at the measurement lines 2 and 3 (Figure 18d,e) point out acute local changes in weld metal chemical composition. Micrographs (Figure 18b,c) reveal that composition variations in the weld metal have  
Figure 16: Tabular data presenting average values of filler metal mixing-% from the data of measurement lines ML1-ML4 in laser cold-wire test welds. Figure 17: Filler metal mixing results from EDS stepwise characterization. (**a–d**) Filler metal mixing-% profiles of measurement lines 1–4 (ML1–ML4) from test weld LCW6 (**e**). In figures (**a–d**) one step between adjacent measurement points in the horizontal axis equals 100 micrometres. induced a change in weld solidification mode from primary austenite to primary ferrite solidification. Microstructural solidification features of both modes can be seen side-by-side and solidified islands of primary ferrite are present in locations where the weld metal contains a high amount of filler metal. Large local spikes in the mixing profiles indicate that the difference between the high and low mixing value levels could be almost 45%-units.