Fig. 1. Finite element model of laser additive spheroidal graphite cast iron. (a) Schematic of laser additive area of ductile iron model； (b) finite element model

Fig. 2. Temperature changes of paths A and B at different powers. （a）Temperature change curves of side path A；(b) temperature change curves of bottom path B； (c) schematic of paths

Fig. 3. Temperature curves changed with time at the monitoring point when the laser additive scanning distance is 0.01 m

Fig. 4. Molten pool depth curves under five critical conditions. (a) The depth of the side of molten pool; (b) the depth of the bottom of molten pool

Fig. 5. Sections at the highest temperature point when the laser additive scanning distance reaches 0.01 m under five critical conditions. (a) P=2 kW，V=1 mm/s； (b) P= 3 kW，V=2 mm/s； (c) P= 4 kW，V=5 mm/s； (d) P=5 kW，V=7 mm/s；(e) P=6 kW，V=10 mm/s

Fig. 6. Contour maps of temperature gradient in z direction under five critical conditions. (a) P=2 kW，V=1 mm/s； (b) P= 3 kW，V=2 mm/s； (c) P= 4 kW，V=5 mm/s； (d) P=5 kW，V=7 mm/s； (e) P=6 kW，V=10 mm/s

Fig. 7. Organization and temperature gradients of the additive layer under P=2 kW and V=1 mm/s. (a) Top organization of additive layer cross-section; (b) horizontal and vertical temperature gradients at the same location