| Stainless Steel-Carbon Steel laminated plates are made of the base layer(carbon steel)and the cladding layer(stainless steel)mainly by explosion,rolling and other processes.Compared with single stainless steel plate or carbon steel plate,stainless steel laminated plates not only have great advantages in corrosion resistance,strength and stiffness,but also can save 30%-50% of production cost.The longer service life and wider application scope make them strong market and price advantages.Laser bending technology is a typical flexible hot forming process.The high-energy laser beam is irradiated on the surface of the plates to be bended.And the instantaneous high temperature causes the thermal stress inside the plates to produce two-dimensional and three-dimensional bending deformation.It is easy to conduct the forming of groove,saddle and spherical crown.In this paper,stainless Steel-Carbon Steel laminated plates were studied.The effects of laser processing parameters,sheet geometry parameters and scanning path on bending forming were studied.The scanning path of spherical canopy forming was planned and the forming accuracy was analyzed by measuring and analyzing the characteristics of the scanned sector sample with laser scanner.The laser concentric arc scanning bending of sector stainless steel laminates was numerically simulated by finite element method.The main contents of the work are as follows:(1)Experiments on concentric arc scanning bending of sector laminates.Under the condition of coupling mechanism,single variable is strictly controlled.Taking the bending angle and surface deformation of sheet metal as the reference basis for the three-dimensional forming accuracy of sector sheet,the influence of the laser processing parameters: laser power P,defocusing H,scanning speed V,scanning times N and geometric parameters of sheet metal: central angle of sector sheet ?,length of free end of sheet metal L,radius of laser scanning line R,radius of pressing sheet r and thickness of sheet metal on bending angle and surface deformation were studied.The bending angle increases with the increase of P,N and R,decreases with the increase of H,V,L and plate thickness,and increases first and then decreases with the increase of ? and r.(2)Measurement of surface deformation characteristics of laser bending parts.Under the technological conditions of temperature gradient mechanism,selecting the sample with obvious deformation in the experiment of forming law.The appearance was measured by laser scanner and data processing by Geomagic,UG.It was concluded that the bending angles at the laser scanning line were different,in which the angle of the end plates were large,however,the middle's were small.The bending produced not only in the direction of scanning line but also bending deformation around the central axis of the fan-shaped plate.In the areas on both sides of the laser scanning line,the surface near the clamping end protruded to the Z-axis and the other end concaved along the radial direction.Finally,based on the bending deformation of the sector plate,six scanning paths based on straight line and circular line were proposed to form the spherical crown,and the forming accuracy was guaranteed.(3)Numerical simulation of laser arc scanning bending.Based on ABAQUS finite element analysis software,a laser concentric arc scanning bending model of stainless steel sector laminated plates was established.A subroutine of moving heat source was written in Fortran language and applied to the model to obtain the calculation results of temperature field,stress-strain field and displacement field.After one scanning,there was a large downward depression at the end of the scanning line.The scanning line was arched in the Z-axis direction,and the scanning line becomes thicker.In this paper,the concentric arc scanning deformation characteristics of sector laminated plates are obtained by experiments and measurements,and the forming principle of sector laminated plates is analyzed by finite element method.Six scanning paths are proposed for spherical crown forming,which is of great significance to study the three-dimensional forming characteristics and mechanism of sheet metal and to broaden the application fields of laminated plates. |
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