Author Affiliations
1 Airport College, Civil Aviation University of China, Tianjin 300300, China2 China North Engine Research Institute, Tianjin 300400, Chinashow less
Fig. 1. Three-dimensional finite element mesh model of valve seat
Fig. 2. Temperature field of laser phase-transformation hardening of valve seat versus time. (a) t=0.09 s; (b) t=5.4 s; (c) t=10.8 s
Fig. 3. Sectional temperature distribution of valve seat at t=10.8 s. (a) Temperature field distribution; (b) temperature contour plot
Fig. 4. Thermal cycle curves for different nodes in phase-transformation hardening area of valve seat at t=5.13 s
Fig. 5. Thermal cycle curves at peak temperature points corresponding to different time along scanning direction
Fig. 6. Temperature field distributions of valve seat for different laser powers. (a) P=1000 W; (b) P=900 W; (c) P=800 W; (d) P=700 W
Fig. 7. Peak temperature of valve seat and depth & width of hardened layer versus laser power. (a) Peak temperature of valve seat; (b) depth & width of hardened layer
Fig. 8. Temperature field distribution of valve seat versus laser scanning speed. (a) V=5 mm·s-1; (b) V=8 mm·s-1; (c) V=10 mm·s-1; (d) V=15 mm·s-1
Fig. 9. Peak temperature of valve seat and depth & width of hardened layer versus scanning speed. (a) Peak temperature of valve seat; (b) depth & width of hardened layer
Fig. 10. Temperature distribution in phase-transformation hardening area of valve seat versus laser spot radius
Fig. 11. Schematic of path nodes in inclined plane
Fig. 12. Temperature field distributions for different laser spot radii. (a) R=1.0 mm; (b) R=1.2 mm; (c) R=1.5 mm; (d) R=1.6 mm
Fig. 13. Peak temperature of valve seat and depth & width of hardened layer for different laser spot radii. (a) Peak temperature of valve seat; (b) depth & width of hardened layer
Fig. 14. Morphology of hardened layer
Fig. 15. Depth and width of hardened layer obtained by numerical simulation and experiment
Temperature T /℃ | Thermal diffusioncoefficient /(mm2·s-1) | Heat conductivity coefficientλ /(W·m-1·K-1) | Specific heatcapacity c /(J·g-1·K-1) |
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25 | 12.859 | 42.370 | 0.465 | 200 | 11.020 | 43.339 | 0.555 | 400 | 8.976 | 41.025 | 0.645 | 500 | 7.975 | 39.332 | 0.696 | 600 | 6.818 | 38.022 | 0.787 |
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Table 1. Thermophysical parameters of RuT300
Element | C | Si | Mn | P | S | Fe |
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Content | 3.5-3.9 | 2.2-2.8 | 0.4-0.8 | <0.06 | <0.04 | Bal. |
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Table 2. Chemical compositions of RuT300 (mass fraction, %)