Study On Technology And Properties Of Laser Cladding With Deflection Angle

Laser cladding technology has been widely used in the manufacturing and remanufacturing of complex parts and large engineering equipment in aerospace,automobile manufacturing,marine and other fields.However,because the workpiece volume is too large to be disassembled or the surface shape is too complex,the laser cladding head needs to deflect a certain angle before processing,and the molten pool morphology is complicated due to the influence of gravity and gas-powder coupling.Firstly,the process test of single deflection angle of cladding head was carried out.It was found that with the increase of deflection Angle,the arc scanning pool morphology along Y-and Y+ directions tended to be flat,and the top of the pool shifted from center to Y-direction along X direction.The influence of process parameters on the molten pool morphology was studied when the cladding head deflected 5°.The optimized multi-pass forming process parameters were as follows:carried gas 9 L/min,protective gas 8 L/min,and powder feeding 12 r/min.Secondly,the process test of double deflection angle of cladding head and substrate was carried out.The scanning direction had little effect on the pool morphology when the two were perpendicular,while the deflection Angle had a certain effect on the height and width of the pool morphology,and the pool morphology was arch shape.The influence of process parameters on the molten pool morphology was studied when the cladding head and substrate were doubledeflected by 5°.The optimized multi-pass forming process parameters were as follows: carried gas 9 L/min,shield gas 10 L/min and powder feeding 16 r/min.Then,the coupling model of gas-powder flow field under two different deflection angles was established,and the trajectory of powder particles and the convergence of particles on the substrate were obtained.When the cladding head was deflected,the convergence center gradually moved up,and the amount of upward movement was the smallest at 5°,which was 0.961 mm.The maximum displacement was 6.132 mm at 35°.When the cladding head and the substrate were doubledeflected,the convergence center also moved upward gradually,and the minimum shift was 0.523 mm when the cladding head was 5°.The maximum displacement was 6.813 mm at 35°.The simulation results provided a theoretical basis for the realtime adjustment of defocus.Finally,the multi-channel multilayer blocks were formed under three conditions of vertical cladding head,deflection of cladding head 5°,and double deflection of cladding head and substrate 5°.The double deflection of cladding head and substrate5° was less than that of the double deflection of cladding head 5°,and the direction of dendrite changed due to the change of deflection angle.The tensile strength of the cladding head and substrate was 524 MPa,the elongation was 25%,the fracture had neck contraction and fewer defected,the layer to layer bonding was good,and the mechanical properties were better than the cladding head deflection of 5°.