Experimental And Simulation Study On Guillotine Shearing Process Of 304 Stainless Steel Sheet

With the rapid development of ships,petrochemicals,new energy vehicles,IT and other industries,the application fields of metal sheets are more extensive,which puts forward higher requirements for its precision slitting technology.During the slitting process,the shear clearance and the radius of the cutting edge have a decisive influence on the quality of sheet metal processing.It is of great significance to study and reveal the influence mechanism of the shear clearance and the radius of the cutting edge on the shearing process of the sheet.In this paper,304 stainless steel sheet is taken as the research object.Firstly,the effect of shear clearance on the shear process of 304 stainless steel sheet is analyzed based on the oblique edge transverse shear experiment and numerical simulation.The results show that with the increase of the shear clearance,the height of the sag angle and the tear angle increase gradually,the height of the shear band first increases and then decreases,and the height of the fracture zone decreases first and then increases,and the relative shear clearance increases,and the shear section quality is best at 4%.In addition,the plastic deformation zone of the sheet increases with the increase of the shear clearance.The shear clearance also has significant effects on the degree of work hardening after shearing.The maximum hardness of the shear edge increases gradually and then decreases.The hardness reaches the maximum at the junction of the shear band and the fracture zone.The shear force has a certain regularity with the change of the shear clearance.The Z-direction shear force F_z gradually increases and then decreases with the increase of the shear clearance.The Y-direction shear force F_y follows the shear clearance.The increase is gradually increasing.Secondly,shear experiments were carried out on different thickness 304 stainless steels by different tool edge transition arc radius.The characteristics of steel section,work hardening and shearing force were analyzed.The results show that the radius of the cutting edge directly affects the crack generation and expansion of the plate.With the increase of the arc radius of the cutting edge,the change trend of the shear section shape of different thickness plates is basically the same,the sag angle and the burr height increase gradually,and the shear band height first increases and then decreases.For the radius of the cutting edge with different thicknesses is 20?m,the height of the shear band reaches the maximum;the depth of the relative hardened layer with different thicknesses-steel sheet increases continuously,but the maximum machining hardening value of the shear edge varies in different thicknesses;F_y keeps increasing,and F_z basically decreases first and then increases.The thinner the steel sheet,the more severe the influence of the radius of the transition arc of the cutting,the greater tensile stress during the shearing process,and the more obvious the warping degree of the steel sheet.Thirdly,the influence of the combination of the shearing radius of the upper and lower cutting edges on the shear process of 304 stainless steel sheet was studied by experiment and simulation.It was found that the shearing radius of the upper and lower cutting edges were both small,the deformation of the plates accumulates,resulting in a plate fracture zone and a reduced shear band height.On the contrary,when the shearing radius of the upper and lower cutting edges were both large,it is more difficult for the tool to cut into the plate,and the plate is more obviously bent by tension,and the sag angle is increased.And the sag angle is more affected by the radius of the upper cutting.The burr is greatly affected by the radius of the lower cutting.In addition,different combinations of upper and lower tool edge transition arc radii have a great influence on the shear quality.It is found that when the transition radius of the upper cutting edge is small,even if the transition arc radius of the lower edge is larger,the better shear section quality can be obtained.Finally,the significance of the synergistic effect of shear clearance and edge transition arc radius on the shear section quality,work hardening degree and shearing force of the sheet was studied,combined with theory,experiment and simulation.And the mechanical model of sheet metal shear processing was established.It is found that the radius of the edge transition arc mainly affects the height of the roll-over and the shearing force.The shear clearance has a more significant effect on the height of the shear band,the height of the fracture zone,the height of the burr and the depth of the work hardened layer.