Research On The Process Optimization Of Plasma Spheroidization Of GH4169 Powder And The Performance Of Laser 3D Printed Parts

Compared with traditional spherical powder preparation methods,RF plasma spheroidization has high energy density,high gas ionization degree,high plasma torch temperature,no electrode pollution,flexible and controllable reaction atmosphere,and can achieve spheroidization of various powders.Processing,preparation of high performance,high-quality powder particles,especially for the preparation of refractory powder particles has great advantages.In this paper,GH4169 powder discarded after repeated laser 3D printing is used.The powder has many defects.In order to improve the recycling of GH4169 powder,the waste powder particles are re-engineered.The RF plasma spheroidization technique was used for powder.The single factor variable method was used to study the effect of powder feeding rate,carrier gas flow rate,and hydrogen flow rate on the spheroidization effect of powder particles during RF spheroidization.The morphology of the powder before and after spheroidization was analyzed to optimize the RF plasma process parameters to ensure the stable production of spheroidized milling.The results show that the optimum process parameters of spheroidized GH4169 powder are: the powder feeding rate is 30g/min.The carrier gas flow rate is 3L/min.The hydrogen flow rate is 20ml/min.The central gas flow rate is 40 L/min.The sheath gas flow rate is 75 L/min.The power is 13 kW.The pressure is 82.68 kPa.The main working gas is argon,and the auxiliary working gas is hydrogen.The surface of the powder particles produced during the spheroidization process is cleaned to further improve the powder properties.The microstructure,chemical composition and powder properties of the powder before and after spheroidization were analyzed.The results show that the microstructure of the spheroidized powder particles mainly includes cell crystals,columnar crystals and a small number of crystallites.The chemical composition of the powder remained basically unchanged before and after spheroidization,and the powder fluidity and bulk density were improved after spheroidization,and the particle size distribution was narrowed.Laser 3D printing of GH4169 powder before and after spheroidization was carried out to analyze the microstructure and mechanical properties of the formed cube and tensile parts.The results show that the regularity of the gap between the spherical powder and the appropriate particle size distribution makes the powder accumulation state the closest and the surface of the molded part is smooth.The microstructure of the powder molded parts before and after spheroidization is similar,mainly including cell crystals and columnar crystals.After spheroidizing,the density and tensile strength of the powder molded part is higher than that of the spheroidized powder molded part,and the microhardness of the powder molded part after spheroidization changes uniformly,and the deviation is small.It shows that the comprehensive performance of the powder molded parts after spheroidization is improved,and the powder morphology and particle size distribution of the laser 3D printing have a significant influence on the quality of the molded parts.