Research On Experiment And Design Of Wide-beam Nozzle In Laser Cladding

Laser cladding technology has become a research hotspot of scientific research institutions and industry at home and abroad because of its ability to perform surface modification with low cost and high performance.In practical applications,spot laser spot laser cladding has a small coverage area and a large number of overlaps,which directly affects the processing efficiency and forming quality.The high-power broadband spot laser greatly improves the working efficiency and improves the surface quality because of its large spot size and small overlap.In the process of broadband laser cladding,how to make the alloy powder into the laser spot area the stablely,uniformly and accurately is of great significance for improving the quality of the cladding.Therefore,the process of wide-band laser cladding powder feeding nozzle and wide-band laser cladding is carried out.Research is of great significance.In this paper,the functional requirements of the laser cladding process for the powder feeding nozzle are analyzed.The parameters and structural requirements of the welding process for the powder feeding convergence are studied.The functional adaptability and processability of the designed nozzle are considered.The coaxial broadband powder feeding nozzle was established and its numerical simulation model was established.The orthogonal experimental design method was used to optimize the nozzle structural parameters,and the DPM discrete phase model and the standard k-? turbulence model were used to numerically study the flow field problems of particles and gases.Calculation.The study found that when the horizontal tilt angle is 70 degrees,the nozzle exit gap is 2.5 mm,and the center distance is 10 mm,the powder feeding nozzle has the best powder feeding effect.Three key process parameters combined experimental schemes were designed based on the central composite test method of the RSM response surface analysis method to study the influence of process parameters on the macroscopic morphology,microstructure and microhardness of the cladding layer.The data of the cladding layer is analyzed by DesignExpert data analysis software.The results show that as the laser power increases,the width of the cladding layer increases,the surface molten pool collapses,the melting height decreases,and the width and height The ratio is increased;the greater the scanning speed,the less the laser energy received by the melt channel per unit area,resulting in a smaller width of the cladding layer,a higher height,and a smaller aspect ratio.In the unit time,the larger the powder feeding speed,the more the powder is melted,so that the width of the cladding layer is larger,and the height is increased,the influence on the height is more remarkable,and the aspect ratio is decreased.The microstructure and microhardness of the cladding layer under different process parameters were observed and measured by metallographic microscope and microhardness tester.The results show that within a certain range,the laser power and the faster scanning speed are larger.And a smaller powder feeding speed is beneficial to improve the surface hardness of the cladding layer.To this end,the designed coaxial broadband laser cladding powder feeding nozzle has the characteristics of accurate,stable and anti-oxidation of powder feeding,and can be applied in practical engineering.The related research work provides a theoretical basis for the process optimization of broadband laser cladding technology,and has certain academic value and engineering practical significance.