Stress Analysis Based On Fluid-structure Coupling Method And Experimental Study On WC Strengthening Of Injection Molding Machine Screw

In order to obtain the high wear-resisting and corrosion-resistant injection molding machine screw coating material that meets the actual production life requirements,and the coating material can meet the cracking and falling off under complex stress state.This study is based on the Fluid-Structure Interaction method first is to simulate the influence of different material viscosity,screw speed and screw material on the force and strain of the screw,especially the screw edge,in the integrated simulation environment of ANSYS.On the basis of numerical simulation.Through the hardness,composition,macroscopic morphology,microstructure,wear rate,corrosion rate,etc.Inspected wear resistance and corrosion resistance of Hot isostatically pressed samples content with 25%,30%,35%,82%WC,and high-velocity oxygen-fuel pressed samples content with 82%WC at different load,temperature,and corrosive medium.Through numerical simulation,it is found that the greater the viscosity of the processed material,the larger the equivalent stress of the screw and the larger the strain.The maximum equivalent stress is 305.45 MPa,which is located at the junction of the screw and the spline,which is much smaller than the maximum allowable of the screw material.The stress is 557 MPa,so the structural requirements are met.In the direction from the inlet to the outlet,the equivalent stress of the screw is gradually reduced.The average compressive stress of the top surface,the back surface and the facing surface of the screw edge are in turn.The reduction,and the three surfaces on the spiral edge are the most compressive stress at the middle of each face.When the screw rotation speed increases,the compressive stress of the spiral backing surface increases,and the compressive stress of the surface is reduced.The surface compressive stress is almost constant and is affected by the screw's own weight.The main strain of the screw in the barrel is in the vertical direction,that is,the screw is “up and down vibration” in the barrel,and the change of the screw material has no influence on the stress of the screw.The rule is that the larger the Young's modulus of the screw material is,the smaller the screw strain is,and the effect variable of the unit body is gradually reduced from the root of the spiral rib,that is,the easy cracking position of the screw edge is located at the root of the spiral.The experimental results show that the wear resistance and corrosion resistance of the sample increase with the increase of WC content,and the wear and tear of the cutting layer under small load,and gradually change into abrasive wear and oxidative wear with the increase of temperature and wear.Under the large load,the adhesive peeling layer wears.The coarse WC grain in the sample can improve the wear resistance and hardness of the sample,but it will greatly reduce the corrosion resistance and strength,so the coarse WC grain is harmful,supersonic flame sprayed samples have better performance than the hot isostatically pressed sintered samples.In the reductive acidic environment,the corrosion resistance of the samples mainly depends on the content of chromium and molybdenum.The increase of chromium content will increase.Corrosion,while molybdenum in the reducing acid corrosion medium will passivate the film on the surface of the sample to prevent further corrosion.The local corrosion mechanism should be galvanic corrosion and intergranular corrosion.