Chinese Journal of Lasers, Volume. 50, Issue 4, 0402021(2023)
Optimization of Laser Polishing Parameters of 304 Stainless Steel and Performance Analysis of Polishing Layer
Figures & Tables(20)
Fig. 2. Schematics of energy density distribution in laser spot and defocus distance. (a) Energy density distribution in laser spot; (b) schematic of defocus distance
Fig. 3. Schematics of laser polishing experimental device and laser scanning trajectory. (a) Laser polishing experimental device; (b) laser scanning trajectory
Fig. 5. Range effect diagrams for different parameters. (a) Laser power; (b) defocus distance; (c) repetition frequency; (d) scanning speed
Fig. 6. 3D surface topographies. (a) Original surface; (b) polished surface under optimal parameters
Fig. 7. Surface profiles of samples before and after laser polishing. (a) Along x direction; (b) along y direction
Fig. 9. Morphologies and EDX diagrams of polished surfaces under optimal parameters
Fig. 10. XRD patterns of 304 stainless steel sample before and after laser polishing
Fig. 11. Locally amplified XRD patterns of 304 stainless steel sample before and after laser polishing
Fig. 12. Grain plots of sample surface before and after laser polishing. (a) Initial surface; (b) polished surface
Fig. 13. Grain sizes of sample surface before and after laser polishing. (a) Initial surface; (b) polished surface
Fig. 14. Polarization curves of 304 stainless steel before and after laser polishing
Table 1. Level values of orthogonal experimental factors
View tableTable 1. Level values of orthogonal experimental factors
Variable Level 1 Level 2 Level 3 Laser power P /W 9 10.5 12 Defocus distance h /mm 2 3 4 Repetition frequency ƒ /kHz 60 70 80 Scanning speed ν /（mm·s-1） 1650 1700 1750
Table 2. Orthogonal experimental design matrix and results
View tableTable 2. Orthogonal experimental design matrix and results
No. P /W h /mm f /kHz ν/（mm·s-1） Rax/μm Ray/μm Ra/μm 1 9.0 2 60 1650 0.3262 0.3156 0.3209 2 9.0 3 70 1700 0.4131 0.4093 0.4112 3 9.0 4 80 1750 0.4622 0.4824 0.4723 4 10.5 2 70 1750 0.2515 0.2497 0.2506 5 10.5 3 80 1650 0.3819 0.3871 0.3845 6 10.5 4 60 1700 0.4152 0.3874 0.4013 7 12.0 2 80 1700 0.2869 0.2655 0.2762 8 12.0 3 60 1750 0.3274 0.3360 0.3317 9 12.0 4 70 1650 0.3812 0.3578 0.3695
Table 3. Range analysis results
View tableTable 3. Range analysis results
Parameter K1 K2 K3 R P/W 0.4015 0.3455 0.3258 0.0757 h/mm 0.2826 0.3758 0.4144 0.1318 ƒ/kHz 0.3513 0.3438 0.3777 0.0339 ν/（mm·s-1） 0.3583 0.3629 0.3515 0.0114
Table 4. Measured surface residual stresses before and after laser polishing
View tableTable 4. Measured surface residual stresses before and after laser polishing
Result Sample 1 Sample 2 Sample 3 Mean value Initial surface residual stress /MPa -112.8±63.1 -124.1±85.3 -118.6±67.7 -118.5±72.0 Polished surface residual stress /MPa 124.3±69.4 152.6±78.6 141.8±58.0 139.6±68.7
Table 5. Surface hardnesses before and after laser polishing
View tableTable 5. Surface hardnesses before and after laser polishing
Result Sample 1 Sample 2 Sample 3 Sample 4 Sample 5 Mean value Initial surface hardness /HV 359 362 346 333 326 345.2 Polished surface hardness /HV 294 296 287 295 288 292.0
Table 6. Self-corrosion potentials and self-corrosion current densities of 304 stainless steel before and after laser polishing
View tableTable 6. Self-corrosion potentials and self-corrosion current densities of 304 stainless steel before and after laser polishing
Surface Self-corrosion potential /V Self-corrosion current density /（μA/cm2） Initial surface -0.028 2.858 Polished surface -0.093 13.836
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Daoqi Li, Tao Wang, Zifan Yang, Yubin Li, Shuwen Wang. Optimization of Laser Polishing Parameters of 304 Stainless Steel and Performance Analysis of Polishing Layer[J]. Chinese Journal of Lasers, 2023, 50(4): 0402021
Paper Information
Category: laser manufacturing
Received: Apr. 7, 2022
Accepted: Jul. 12, 2022
Published Online: Feb. 2, 2023
The Author Email: Wang Tao (wtao_1@163.com)
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