in this paper, the direct extrusion process of bimetallic rods in conical dies is analyzed by an improved upper bound method. the deformation zone is subdivided into six smaller zones and by considering a non-spherical entrance boundary to the deformation zone, a velocity field is presented which is different from velocity fields employed in previous studies. the total power consumption of the ...

the accumulative roll bonding (arb) as a severe plastic deformation (spd) procedure aimed at enhancing the mechanical properties of metals and alloys. in the present study, a new slab method is proposed for estimating the forming stress field for cold extrusion of metals cross the alumina interlayer powder particles by accumulative roll bonding process. plastic deformation behavior of the metal...

Autonomic control of food extruders has attracted considerable in recent years. With limited understanding of the complex physio-chemical interactions during the food extrusion process, designing a control system for food extruder is not easy. The common approach is to determine the operating conditions and then to maintain these values as closely as possible using various control loops, if not...

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...

The accumulative roll bonding (ARB) as a severe plastic deformation (SPD) procedure aimed at enhancing the mechanical properties of metals and alloys. In the present study, a new slab method is proposed for estimating the forming stress field for cold extrusion of metals cross the alumina interlayer powder particles by accumulative roll bonding process. Plastic deformation behavior of the metal...

In this paper, a generalized expression for the flow field in axisymmetric extrusion process is suggested to be valid for any dies and the boundary shapes of the plastic deformation zone. The general power terms are derived and the extrusion force is calculated by applying upper bound technique for a streamlined die shape and exponential functions for shear boundaries. It is shown that assuming...

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...

Twist extrusion process is a rather new route to produce highly strained materials. In this process, severe plastic deformation is applied by large shear strains. In current article, required energy for twist extrusion by use of admissible velocity field together with the upper bound technique is predicted. The proposed model is capable of considering the effect of various parameters such as di...

Abstract: In this paper, the forming process of a central hub by radial-forward extrusion is analyzed by using the finite element software, ABAQUS. Radial-forward extrusion is used to produce hollow parts that generally feature a central hub with radial protrusions. Effective design factors such as mandrel diameter, die corner radius, die fillet radius, mandrel corner radius, tube wall thick...