On the issue of selecting and optimizing parameters of continuous laser welding of cast iron

OBRABOTKAMETALLOV Vol. 23 No. 3 2021 technology Ta b l e 5 Grey relational grade results № x 1 x 2 x 3 x 4 g Rank 1 0.48 1 0.58 0.33 0.6 2 2 0.61 0.62 0.7 0.33 0.56 4 3 1 0.4 1 0.33 0.68 1 4 0.33 0.62 0.36 0.37 0.42 8 5 0.33 0.33 0.33 0.33 0.33 9 6 0.63 0.33 0.55 0.52 0.51 5 7 0.33 0.52 0.33 0.63 0.45 6 8 0.36 0.36 0.33 0.73 0.45 7 9 0.53 0.33 0.44 1 0.57 3 Fig. 4. Main effects plot for Grey relational grade Grey relational grades averaged over the factor variation levels are shown in Fig. 4. The horizontal line on the graph corresponds to the average relational grade in the experiment. The graph in Fig. 4 and the data in table 5 show that the most attractive parameters from the viewpoint of obtaining a maximum penetration weld seam with a minimum width, convexity (concavity) and hardening zone are the minimum power and maximum welding speed, which corresponds to mode No. 3. In addition, at the given parameters, the process maximum productivity and economy are achieved. Let us require fulfilling these conditions in the optimization problem:         → → − = + + = −   + = ≤ ≤ ≤ ≤  min max 1.979 2.889 0.021 0.079 0.083 0.00 0.6 1.3 14 56 p v d p v m p v d m t p v where p – is laser power , kW; v – is welding speed, mm/s; d – is melting zone penetration, mm; m – is hardening zone size from the solid phase, mm; t – is weld seam penetration, mm. Restrictions on the penetration of the melting and hardening zones were taken in accordance with the obtained regression models (Table 2), the intervals for varying the power and speed were taken in accordance with the levels of factors adopted during the experiment (Table 1).