It is generally known that severe plastic deformation processes with back pressure not only apply higher hydrostatic stress and more deformation compared to what a regular process can apply to a workpiece but also prevent surface defects in the workpiece during the process. Hydrostatic cyclic expansion extrusion (HCEE) was developed recently for processing long ultrafine-grained metals and allo...

The hydrostatic extrusion is a new method of extrusion process. The most important advantage of this method is reduction of friction and close tolerance for the coating thickness. In this study, the hydrostatic extrusion simulation of bimetallic wires has performed using of finite element method. In the following the advantages of hydrostatic extrusion compared to the direct extrusion are prese...

The hydrostatic extrusion is a new method of extrusion process. The most important advantage of this method is reduction of friction and close tolerance for the coating thickness. In this study, the hydrostatic extrusion simulation of bimetallic wires has performed using of finite element method. In the following the advantages of hydrostatic extrusion compared to the direct extrusion are prese...

Strain distribution of Al 1100 was numerically investigated during cyclic expansion extrusion (CEE) process using finite element method (FEM). Die angle, corner fillet radius and die chamber diameter were considered as die parameters and friction factor and number of passes as process parameters. The effects of these parameters were investigated on the effective strain and strain homogeneity in...

Introduction Bar extrusion is a process in which a block of metal (billet) is forced to flow by compression through a tool (die) opening of a smaller crosssectional area than that of the original billet. There are two basic types of bar extrusion: direct and indirect. The most important and common method used is the direct extrusion (Lange 1988). Figure 1 shows the principle of direct bar extru...

The objective of this paper is to investigate the viscous shear heating effect on the formation of minimum film thickness in inlet zone of the hydrostatic extrusion process as function of various operating parameters. Minimum film thicknesses in the inlet zone has been evaluated at various extrusion speeds, material parameters, extrusion pressures, and die semiangle for extrusion of low strengt...

Deformation of the material during cyclic expansion extrusion (CEE) is investigated using upper-bound theorem. The analytical approximation of forming loads agrees very well with the FEM results for different amounts of chamber diameter, friction factor and also for lower die angles. However, the difference between analytical and numerical solution increases at higher die angles which are expla...

The mechanical properties of titanium Grade 2 subjected to the hydrostatic extrusion technique (HE) were investigated. The hydrostatic extrusion technique is a method which refines the titanium grains to a nano-metric size. Compared with coarse grained titanium (CG-Ti), nanocrystalline titanium (NC-Ti) is characterized by a much higher yield stress, tensile strength and microhardness. The yield...