New Design Of 316L Stainless Steel Cutting Nozzle And Simulation Of Its Forming Process

Cutting nozzle is the key component of a flame suction cutting torch.It is mainly used for cutting steel plate,iron plate,copper plate,and other metal materials in a wide application market.The cutting nozzle is a nondurable part,which are consumed in a large amount every year.Its form factor,selection of materials,processing methods,and process parameters will play a major role on the final performance of cutting nozzle.In this paper,the shapes of the inner pipe,the seat,and the shell of the cutting nozzle are all modified,and a new type of cutting nozzle is designed and developed.According to the velocity vector diagram of the cutting nozzle fluid,the flow velocities of the cutting nozzle before improvement,the first improved cutting nozzle,and the final improved cutting nozzle increase in sequence.The maximum flow velocities of the improved cutting nozzle are 684 m/s,782 m/s,and 901 m/s,respectively.It is the mixture of gas outlet velocity which has be evidently enhanced compared with the former two.From the velocity nephogram,it can be seen that in the air,the jet velocities of the improved cutting nozzle,the first improved cutting nozzle,and the final improved cutting nozzle reached 638 m/s,630 m/s,and 700 m/s respectively.It can be seen that the jet velocities of the new improved cutting nozzle are obviously improved and more suitable for cutting,and their flame shapes are more concentrated,so that the impact force and temperature are more concentrated during cutting.The cutting speed is consequently more efficient,resulting in a stronger cutting ability.It proves that the new design of the improved cutting nozzle is feasible.The raw material was changed from copper to 316 L stainless steel.Metal powder injection molding process is used to process.The injection molding simulation of the new cutting nozzle is carried out by the software of ANSYS FLUENT fluid simulation.The results of pressure analysis,velocity analysis,and temperature analysis show that the optimum process parameters of the improved cutting nozzle are injection pressure as 110 MPa,injection speed as 0.82 m/s,model temperature as room temperature.The results of the two-phase analysis also show that the injection rate of 0.82 m/s is feasible.According to the simulation results,the actual production of the new cutting nozzle is carried out.The main processing processes are injection molding,degreasing and sintering.Finally,the density,hardness,service life and micro-morphology of the finished products were analyzed and tested.Injection molding is set according to the best simulated process parameters;the method of degreasing is solvent degreasing plus thermal degreasing.Solvent degreasing is to immerse the raw billet of the cutting nozzle in trichloroethylene solvent for 7 hours,the degreasing temperature is 70?C.Thermal degreasing refers to heating from room temperature for 1 hour to 220?C and holding for 2 hours,then heating to 500?C and holding for 2 hours at 1?C/min,and sintering temperature is chosen to rise from 5?C/min to 1360?C and keep for 1 hour,then drop to room temperature at 10?C/min.There are many defects in the material of the new cutting nozzle,but the pore size is not large,and its relative density is 95.61%.The average Vickers hardness at the outlet,the interior and the outlet of the new cutting nozzle is 108 HV,105 HV,and 109 HV,respectively.The hardness of the new cutting nozzle is higher than that of the traditional cutting nozzle.The average service life is about 200 hours,which is much higher than the average service life of 40 hours for ordinary cutting nozzles.Therefore,the results show that the cutting nozzle has good performance,which proves that the process parameters are in line with the production requirements.