Establishment Of Modify Yield Model And Finite Element Simulation During Powder Compacting Process

Powder metallurgy(PM) parts has been widely applied in industry, such asaerospace, ransportation, onstruction engineering, mechanical engineering,electrochemical engineering environmental engineering and so on,mainly because ofthe characteristics of structural materials and functional materials. To obtain morereliable PM products, many secondary processes are applied to PM preforms, amongwhich powder forging is particularly attractive because it allows the cost and materialsaving advantages of conventional PM, as well as the high production rates andproperty enhancement of forging. The Paper has systemieally studied the deformationlaw and the densifieation mechanism during Powder forging Process(especially coldforging) based on the eombined methods of Theoretical study, experimental testingand nurnerical simulation.In theoretical study field of Plastic forming for Porous metal matetials, accordingto a modified yield model has been established based on the assumption ofcontimuum theory by modifying the expression of possion’s ratio and relativedensity and flow rule model.In experiment study field, according to copper powder, ferrous powder andaluminium powder experimental results of upsetting, we fix the material constant mby fitting the relationship between axial strain and relative density, and furtherobtain the specific expression of modified yield model. The theoretical results (suchmaso rdeelal tiaonnds hriephl ab tthievtoews eede oenfn speioxtysp seaiorinnmd’ sed rniatfsft,eio wre and relative density, coefficient of flow stresshnitc hy iveeldri fmy othdee lv atrliadcikty inan dJ1u n i veJr2′plane) arecompared witsality of thenew model.In finite element numerical simulation study field, author simulated the processof powder upsetting forming by using the software of MSC.MARC and the effect ofdifferent friction factor, compaction velocity on the deformation law and thedensifieation mechanism during Powder upsetting.This research provides a theoretical basis for the plastic processing technologyand has important significance on enriching and precision plastic forming theory ofporous material...