Study On Localized Sheet-bulk Forming And Its Influence On Material Properties

Sheet-bulk metal forming(or forging forming)is a kind of forming method for the plastic deformation of slab to obtain some local non-uniform thickness geometric features.In recent years,the technology has gained a lot of attention due to its special advantages in satisfying structural lightweight and reducing process.However,sheet-bulk metal forming is different from that of traditional plate forming or volume forming in the aspects of force and deformation.At the same time,the widely used metal plates in practice have been subjected to rolling and subsequent processing,which can form obvious anisotropy due to the preferential orientation and fiber structure of grain.In addition,the metal will also appear in the process of cold plastic deformation work hardening etc.Phenomenon,therefore,further study of rolling slab related law of plastic deformation volume,master sheet metal bulk forming impact on the microstructure and macro properties of the slab,it is very necessary.In this paper,the plastic forming process of sheet material and its effect on the properties of rolled slab are studied.In this paper,the influence of process factors such as forging process and friction on forming is discussed.In this paper,the microstructure and the evolution law of microstructure and macroscopic mechanical properties of rolled plate are analyzed with 16MnCr5 steel plate and 6061 aluminum plate.The main conclusions are as follows:(1)the friction state of different contact parts of the mold and the slab has different influences on the forming process.Among them,friction within the mold cavity can hinder the flow of metal,which is not conducive to filling.In addition,the friction force of the contact part of the plate can increase the resistance of the metal to the external flow,which is beneficial to the tooth filling.Therefore,the filling capacity of the cavity can be improved by adjusting the local friction force and without increasing the load.(2)local shape deformation area has significant effect on the tensile properties of the sample: circular pressure tank sample pulled the maximum tension value maximum,V groove sample maximum tension times,and the rectangular pressure tank sample the most easily broken This phenomenon is related to the stress distribution characteristics of the local deformation region in the specimen stretching,especially the stress concentration.(3)with the increase of the deformation amount,the original ellipsoidal grains that are elongated along the rolling direction will be broken.Due to the increase of dislocation density,the hardness of the material can be significantly improved.Measure the different orientation of specimen deformation zone profile microhardness,found 90 ° orientation average highest hardness on the surface of the specimen deformation zone,and 45 ° orientation lowest average hardness on the surface of the sample.(4)the results of microhardness test for the finished product of the synchronizer gear ring showed that the anisotropy was also present in the parts after the sheet volume was formed;Carburizing will improve the overall surface hardness of the parts,but will not change the original hardness distribution.