Research On Influence Of Forging Ratio To Mechanical Properties And Microstructure Of Forgings

Microstructure and mechanical properties of forgings are related with many factors, and the forging ratio is one of the most significant factors which influence the quality of the forging. Forging ratio is an indication of metal deformation degree of forging. The greater forging ratio, the higher deformation degree of forgings. And the deformation degree, which is directly related to the eventually inclusion size of material, the eutectic carbide fragmentation degree of material, and the fiber direction and density of material after eventually forming, have a significant impact on the comprehensive properties of materials. Research on influence of forging ratio to mechanical properties and microstructure of forgings has very important practical significance for effective controlling properties of forgings.Hot-upsetting experiments of45#rolled steels with various forging ratio were conducted at same heat treatment condition to acquire various forging ratio forgings, and through the secondary development of numerical simulation software, acquired the forgings’ distribution of forging ratio, equivalent strain, temperature field and other parameters, and provide the basis for selection of the mechanical properties of the sample. The simulation results show that, forging ratio (the degree of plastic deformation) distribution with different foraging ratio forgings is not uniform, were divided into large forging radio region, average forging ratio region and small forging ratio region.Designed mechanical properties sample selection program of different forging ratio forgings. Tension tests and impact test of forgings with different forging ratio to investigate how the forging ratio influences the mechanical properties of rolled steels. Results of mechanical properties experiments show that, in the same heat treatment conditions, Strength and toughness of forgings can be significantly increased by plastic deformation with a certain forging ratio, when the forging ratio reached a certain value, structure and property changes of forgings is intense,its strength increased to the best, but the toughness decreased.Microstructure observation of forgings with different forging ratio investigates how the forging ratio influences the microstructure of rolled steels. The results show that, at the same strain rate conditions, the forging ratio (the degree of plastic deformation) of forgings were more greater, the dynamic recrystallization of forgings were more obvious, when forging ratio reached a certain value, the original grain will be replaced by new recrystallized grains, there is a completely dynamic recrystallization.Based on the analysis of upsetting of the anvil causes of forging ratio uneven in plate upsetting, three kinds of process scheme for improving forging ratio uniformity of rolled steel upsetting were determined, were changing the boundary conditions between billet and mold, blank shape and forming methods. Forging radio and geometrical size uniformity of various measures’ forgings were comparative analyzed with numerical simulation. The simulation results show that, the change of deformation mode of plate upsetting can effectively improve the forging ratio and geometrical size uniformity.