Strains under Angular Pressing of a Strip from a Cylindrical Billet

The scheme of non-equal channel angular pressing (non-ECAP) of a magnesium billet has been analyzed. The modeling was performed by DEFORM-2D software. A high level of strain is shown to be achieved during non-ECAP. It leads to more homogenous structure refinement of magnesium and plasticity improvement that could favorably affect the subsequent deformation of a Mg-strip by cold rolling. At non-ECAP-process, the upper part of the strip is noted to be hardened more than the lower one. The lower part is supposed to be formed by extensional strain mainly, meanwhile for the upper one, the prime mechanism is likely to be shear strain. Based on hardness measurement of the samples cut from the obtained Mg-strip, conclusions have been made about the influence of the accumulated strain during non-ECAP on the strength properties of the strip.

Analysis of deformation of non-stiffbillets depending on the clamping scheme and cutting modes

Clamping of non-stiff thin-walled billets on machine tools for various machining operations is accompanied by the appearance of significant deformations in them. The new approach to the analysis of the billetdeformations from the clamping forcesis developed on the base of finite element method. The calculation error of billet fixing is estimatedon the example of a cylindrical billet. For various fixing schemes the corresponding boundary conditions are developed. The error analysis results obtained by finite element method for various fixing schemes, billet geometry and cutting modes are presented.

Numerical Simulation of Al 6062 Alloy Deformation Behavior Using Equal Channel Angular Extrusion Process with Different Die Angles

The equal channel angular extrusion (ECAE) is one of the most important methods used for bulk metal forming. In which die angles are the most importent parameter. This paper attempts to determine the effect of different die angles during ECAE process for 6062 aluminum alloy deformation. Numerical simulations are performed for ECAE process on cylindrical billet of 6062 aluminum alloy at a constant frictional coefficient (μ) of 0.08 and punch speed of 15 mm/sec. Die has made with inner corner angles of (φ) =105°, 115°, 125°and 135° by fixing the outer corner angle (ψ) of 6°, punch is designed with a radii (R) of 4.75mm and height of 50mm. From the simulation results, tha data has been obtained in the form of load stroke behavior, and energy consumend during the punch stoke. It is observed that the maximum load and more energy consumption during the process is noted for lower angle.

Analysis of Transient Thermal Processes in the Steel Billet at Different Regimes of Air Cooling

The work deal with numerical modeling of the air cooling of cylindrical billet. The solution is carried out taking into account the dynamics of environmental air, radiation heat transfer, turbulence of the flow and conjugate heat transfer. The modeling process was realized in the accordance with a scheme of manufacturing of alloys with the structure of lower carbide-free bainite. A mathematical model has been developed by means of the finite-volume software Ansys CFX. The most effective mechanisms to control the cooling speed of the billet have been identified during numerical experiments.

Cold Piercing of Cylindrical Aluminum Billet with Counter Punch Pressure

To make a hole with a high aspect ratio (depth/diameter) for lightweight structural components, piercing of cylindrical billet of aluminum alloy was carried out against a counter pressure on a servo-controlled double axis press. To obtain smooth shear surface of pierced hole, the counter pressure was applied to the billet by a counter punch from the opposite side of a piercing punch during piercing. Irrespective of amount of clearance of die–piercing punch, ratio of the length of shear surface/depth of pierced hole in the pierced billet reached about 0.9 by applying a counter punch pressure of 0.2 GPa. The maximum aspect ratio of the hole in the proposed piercing method was estimated to be approximately of 15 for the aluminum billet from viewpoints of buckling and strength of the punch.

Experimental Study of Hot Forming Process by Direct Resistance Heating

In order to increase heating efficiency and decrease heating time, a new hot-forging method by means of direct resistance heating was investigated in this paper. Based on the approach, the hot upsetting experiments with cylindrical billet of 42CrMo4 were performed. Moreover, the influence of the multi-layer aluminium foils inserted between the billet and the die as a forming condition on heating and forming was researched. The results of the experiments show that prior to forming the billet could be heated quickly to forming temperature in about 10 seconds. During the upsetting process the billet cooling rate was effectively decreased and the forming time was extended in relation to the resistance heating. The insertion of multi-layer aluminium foils not only improved the efficiency of the heating, but also avoided the plastic deformation of the die and the occurrence of cracks on the billet’s surface. Keywords: Resistance heating, Hot forging, upsetting, Aluminium foils Introduction