Strain Analysis And Crystal Plasticity Finite Element Simulation Body Diameter Plastic To Forging Process

Radial forging of barrel is a complex plastic forming process, and the process includes many local forming stages. The concept of local forging ratio is proposed, and the relationship of local and whole forging ratio is derived. The increment strain of single forging is derived from local forging ratio based on constant volume and small deformation principle, and the whole strains of radial forging are obtained by accumulation of increment strains. The traditional FEM is used to solve the whole strain, and the solutions are very consistent by analytic method and FEM.The sinking stage and forging stage are proposed in radial forging process of barrel’s bore, and the effects on plastic strain of their forging ratios are studied by the above method of strain analysis. Under the condition that whole forging ratio is constant, the effects on plastic strain of inner surface and forging force are studied by change the forging ratio of sinking and forging stage each other. The requirement of bore’s forming is discussed, and the actual example of forging is used to prove the requirement. The calculation results indicate that too large forging ratio of sinking stage can result in tension strain increase and compress strain decrease on the inner surface of barrel, so it is bad to bore’s forming. In the case of whole forging ratio remain unchanged, the forging force growth quickly with the growth of forging ratio of sinking stage, it will result in power consumption grow quickly, and the life of hammers decrease too.To study the evolution of barrel’s texture, the crystal plastic finite element method (CPFEM) is introduced. The subroutine UMAT which is used into CPFEM is studied, and the Asaro hardening model is used in the constitutive law. The different poly crystalline geometry models are established base on Voronoi method, and the models are imported into ABAQUS by script interface and element sets methods. The simulation of tensile test is implemented by CPFEM, and the parameters of constitutive model are estimated by fitting the stress-strain curve of tensile test. The evolution of grain’s orientation is studied in the necking zone; moreover, the uneven character of plastic strain in the tensile sample is studied.The polycrystalline FEM model of barrel in the process of radial forging is established by ABAQUS and the process of deform is simulated. During sinking and forging stage, the deformed characters of grains on the inner and outer surface of barrel are studied, and the evolution of grain orientation is gain by pole figures. The result indicate that the rotation angle of grain on the inner surface larger than that of grain on the outer surface. In deformed barrel and single grain, the plastic strain are studied, the result indicate that the plastic strain in the deformed barrel and single grain are uneven, but the plastic strains in all direction are consistent with strains each other by analytic method and traditional FEM.