A novel type of precision cropping machinery using rotary striking action

2009 ◽  
Vol 223 (8) ◽  
pp. 1965-1967 ◽  
Author(s):  
Y Tang ◽  
S D Zhao ◽  
Z W Wang
Keyword(s):  
Cross Section ◽  
Radial Displacement ◽  
Cold Forging ◽  
Cold Extrusion ◽  
High Quality ◽  
Rotary Swaging

In this article, novel precision bar cropping machinery, with a modified rotary swaging machine, which has been extended by the addition of a stroke adjuster, was designed and built. By adjusting the strike frequency and the radial displacement, a crack can be made to propagate quickly and regularly, leading to a final regular separation of the bar. Precision cropping experiments on several metal bars were conducted, which can be directly used in the subsequent process, such as cold-extrusion and cold-forging and so on because of the high-quality cross-section, high geometric and weight precision using this cropping device.

Increasing in rationality of using of cold extrusion in production of parts such as steel deep glasses

2021 ◽  
pp. 258-267
Author(s):  
A.M. Dmitriev ◽  
N.V. Korobova
Keyword(s):  
Production Process ◽  
Fatigue Resistance ◽  
Rational Design ◽  
Large Scale ◽  
Cold Forging ◽  
Cold Extrusion ◽  
Quality Of Products

The limited use of cold volume stamping for the production of parts only for narrow traditional range of such parts in mass and large-scale productions is shown. Original technological techniques that improve the quality of products and the punches fatigue resistance are developed to expand the application of this technology to new types of parts. Such techniques used at various stages of the production process by cold forging of deep steel glasses are described. The value of rational design of stamps and the example of design of well-proven production stamp are shown.

Numerical and Experimental Modelling of an Air Flow Field in the Chamber of a Rectangular Cross-Section Contraction

2015 ◽  
Vol 769 ◽  
pp. 161-165
Author(s):  
Vladimira Michalcova ◽  
Sergej Kuznetsov ◽  
Lenka Lausova ◽  
Iveta Skotnicova
Keyword(s):  
Cross Section ◽  
Rectangular Cross Section ◽  
Optimal Shape ◽  
High Quality ◽  
Ansys Fluent ◽  
Experimental Modelling ◽  
Software Models ◽  
Turbulent Characteristics ◽  
Fluent Software ◽  
Enclosed Chamber

The article describes the study of turbulent characteristics in the enclosed chamber of a rectangular corss-section nozzle using numerical calculations. Suitable Ansys Fluent software models were selected based on the measurements results comparison in an aerodynamic tunnel as the fluid exits the nozzle. Special attention is paid to profile velocity near the peripheral wall of the observed enclosed chamber in order to confirm the optimal shape of the contraction and thus take steps towards a high quality velocity field.

Comparison of Microstructure and Mechanical Properties of Semi-Solid Castings Produced Using Billets Made by EMS and SEED

2014 ◽  
Vol 217-218 ◽  
pp. 332-339 ◽  
Author(s):  
Xiao Kang Liang ◽  
Da Quan Li ◽  
Pascal Côté ◽  
Stephen P. Midson ◽  
Qiang Zhu
Keyword(s):  
Mechanical Properties ◽  
Cross Section ◽  
Dendritic Structure ◽  
Casting Process ◽  
Grain Structure ◽  
High Quality ◽  
Microstructure And Mechanical Properties ◽  
Grain Structures ◽  
Heat Treated ◽  
Semi Solid

The spheroidal grains in billets used for semi-solid casting are generally manufactured by electromagnetic stirring (EMS) during the casting process. This method however, is not economically applicable for small quantities of the thixo billets. Swirled Enthalpy Equilibration Device (SEED) has been developed as a rheocasting process, and the SEED process is of interest for developing new thixo alloys, as well as for optimizing the thixocasting processes for high quality components. The objective of this paper is to compare the microstructure and mechanical properties of aluminum alloy 319s billets and castings produced using EMS and SEED feed materials. The experimental results show that for as-cast billets made from SEED process, a well-developed spheroidal grain structure is distributed throughout the cross-section of the billet, while for as-cast EMS billets, the grain structure is inhomogeneous, i.e., a dendritic structure was present adjacent to the surface of the billet, while a uniform, spheroidal structure was present at the centre. After the thixocasting process, however, the both SEED and EMS billets have well-developed, spheroidal grain structures. Mechanical properties of thixocast and T61 heat treated components are comparable for the both SEED and EMS billets.

Research of Hot Ductility for ML40Cr with Cold Forging Steel

2011 ◽  
Vol 284-286 ◽  
pp. 1697-1700
Author(s):  
Zhan Ying Liu ◽  
Hong Qi Zhang ◽  
Yue Hua Hou
Keyword(s):  
Cross Section ◽  
Cold Forging ◽  
Hot Ductility ◽  
Temperature Range ◽  
Cross Section Area ◽  
Section Area

Hot ductility of ML40Cr steel at the temperatures from 700°C to 1300°C was measured on simulator Gleeble-1500. The results are as follows: the hot ductility reduces in temperature range of 950°C to 1300°C, and increases in temperature range of 700°C to 950°C. The reduction of cross section area is reduced obvious in temperature range of 950°C to 1300°C, and Extensibility fall is slow. The best hot ductility of ML40Cr steel is 950°C.

GROWTH OF ZnO NANOSTRUCTURES ON ZINC AND Pt SUBSTRATES

2007 ◽  
Vol 06 (01) ◽  
pp. 23-30 ◽  
Author(s):  
N. TABET ◽  
M. FAIZ ◽  
A. AL-OTEIBI
Keyword(s):  
Melting Point ◽  
Cross Section ◽  
Vapor Deposition ◽  
Type Structure ◽  
Metallic Zinc ◽  
Zno Nanostructures ◽  
High Quality ◽  
Hexagonal Shape ◽  
Dry Oxidation ◽  
Uniform Cross Section

Nanocrystalline ZnO of various shapes was obtained without the use of catalysts by dry oxidation of metallic zinc. Oxidation treatments performed below the melting point of Zn (T m = 419°C) led to the formation of flakes-type structure. At 500°C, long nanofibers of circular and uniform cross section covering the surface of the oxidized samples were observed. At 600°C, large density of cone-shape needles covered the oxidized surface. High quality nanocrystals of hexagonal shape were obtained by vapor deposition on Pt substrate. XRD results showed that the lattice parameters of the needles are 1% smaller than those of microcrystalline ZnO .

SYNTHESIS AND CHARACTERIZATON OF HIGH-QUALITY GaN NANORODS WITH TRIANGULAR CROSS SECTION

2005 ◽  
Vol 19 (15n17) ◽  
pp. 2859-2864 ◽  
Author(s):  
X. X. WU ◽  
J. J. FU ◽  
Y. YANG ◽  
Q. WU ◽  
Z. HU ◽  
...  
Keyword(s):  
Optical Properties ◽  
Cross Section ◽  
Optoelectronic Devices ◽  
Hexagonal Structure ◽  
Electron Microscopic ◽  
High Quality ◽  
Triangular Cross Section ◽  
Transmission Electron ◽  
Transmission Electron Microscopic ◽  
Potential Applications

High-quality GaN nanorods with triangular cross section were synthesized via a simple chloride-assisted vapor phase epitaxy method. High-resolution transmission electron microscopic observations show that the synthesized GaN nanorods are single crystal with wurtzite hexagonal structure. Raman and photoluminescence measurements were also carried out to study the optical properties of the as-prepared GaN nanorods, which suggests the potential applications in optoelectronic devices.

scholarly journals Simulation of a Steel Wire Straightening Taking into Account Nonlinear Hardening of Material

2012 ◽  
Vol 2 (6) ◽  
pp. 320-324
Author(s):  
I. Khromov ◽  
R. Kawalla
Keyword(s):  
Residual Stresses ◽  
Physical Model ◽  
Cross Section ◽  
Steel Wire ◽  
Small Diameter ◽  
Bending Moment ◽  
High Quality ◽  
Deflected Mode ◽  
Nonlinear Hardening

Straightening is used to ensure the straightness of a rod workpiece as well as to redistribute or reduce the residual stresses in a finished product. The accuracy of modeling the operation of this kind plays an important role when manufacturing high quality ropes and cables of a small diameter. The physical model of alternating wire bending in a straightener has been considered in the paper. Computer methodology has been developed to calculate deflected mode and internal bending moment in a cross section of a wire at the different stages of deformation, which allowed taking into account nonlinear hardening of the material.

scholarly journals A Combined Cold Extrusion for a Drive Shaft: A Parametric Study on Tool Geometry

Materials ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2244
Author(s):  
Tae-Wan Ku
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Groove Depth ◽  
Spur Gear ◽  
Finite Element Simulations ◽  
Drive Shaft ◽  
Cold Forging ◽  
Cold Extrusion ◽  
Tool Geometry ◽  
Shoulder Angle

Parametric investigations related to shoulder angle on tool geometry for a combined cold extrusion of a drive shaft, which consisted of spur gear and internal spline structures, were conducted through three-dimensional FE (finite element) simulations. The drive shaft was required to be about 92.00 mm for the face width of the top land on the spur gear part and roughly 22.70 mm for the groove depth of the internal spline section. AISI 1035 carbon steel material with a diameter of 50.00 mm and a length of 121.00 mm was spheroidized and annealed, then used as the initial billet material. A preform as an intermediate workpiece was adopted to avoid the excessive accumulation of plastic deformation during the combined cold extrusion. Accordingly, the cold forging process involves two extrusion operations such as a forward extrusion and a combined extrusion for the preform and the drive shaft. As the main geometric parameters influencing the dimensional quality and the deformed configuration of the final product, the two shoulder angles of θ1 and θ2 for the preform forging and the combined extrusion were both considered to be appropriate at 30°, 45°, and 60°, respectively. Using nine geometric parameter combinations, three-dimensional finite element simulations were performed, and these were used to evaluate the deformed features and the geometric compatibilities on the spur gear structure and the internal spline feature. Based on these comparative evaluations using the numerically simulated results, it is shown that the dimensional requirements of the target shape can be satisfied with the shoulder angle combination of (45°, 45°) for (θ1, θ2).

Part II. The Flattening of Monocoque Cylinders

1938 ◽  
Vol 42 (328) ◽  
pp. 302-319
Keyword(s):  
Variational Method ◽  
Potential Energy ◽  
Cross Section ◽  
Radial Displacement ◽  
Bending Moment ◽  
Experimental Investigations ◽  
Pure Bending ◽  
Centre Line ◽  
Thin Walled ◽  
The Cross

It is known from both theoretical and experimental investigations that St. Venant's assumption on the constancy of the shape of the cross section of girders in pure bending does not hold true in case of thin-walled sections. The greater flexibility than calculated according to ordinary bending theory of initially curved tubes, as experimentally found by Professor Bantlin, was perfectly explained by Professor von Kármán in 1911 on the assumption of a flattening of the section.In 1927 Brazier with the aid of the variational method determined exactly that the shape of an originally circular thin-walled bent cylinder corresponding to the least potential energy is quasi elliptical and that the cross section of the cylinder, therefore, must flatten, even if the centre line of the cylinder was originally straight. In consequence of the flattening St. Venant's linear law for the curvature loses its validity and the curvature increases more rapidly than the bending moment. For a certain value of the curvature the bending moment is a maximum, and after this value was reached the curvature increases even if the applied moment remains unchanged or decreases, fulfilling thereby the criterion of instability. This instability occurs when the rate of flattening, i.e., the maximum radial displacement of any point of the circumference of the tube divided by the original radius of the tube, will equal 2/9.

scholarly journals An analytical solution for static problems of curved composite beams

2019 ◽  
Vol 6 (1) ◽  
pp. 105-116 ◽  
Author(s):  
István Ecsedi ◽  
Ákos József Lengyel
Keyword(s):  
Analytical Solution ◽  
Cross Section ◽  
Radial Displacement ◽  
Fundamental Solutions ◽  
Composite Beams ◽  
Shear Stresses ◽  
Equilibrium Equations ◽  
Euler Beam ◽  
Internal Forces

AbstractAn analytical solution is presented for the determination of deformation of curved composite beams. Each cross-section is assumed to be symmetrical and the applied loads are acted in the plane of symmetry of curved beam. In-plane deformations are considered of composite curved beams. Assumed form of the displacement field assures the fulfillment of the classical Bernoulli-Euler beam theory. The curvature of beam is constant and the internal forces in a cross-section is replaced by an equivalent forcecouple system at the origin of the cylindrical coordinate system used. The internal forces are expressed in terms of two kinematical variables, which are the radial displacement and the rotation of the cross-sections. The determination of the analytical solutions of the considered static problems are based on the fundamental solutions. Linear combination of the fundamental solutions which are filling to the given loading and boundary conditions, gives the total solution. Closed form formulae are derived for the radial displacement, cross-sectional rotation, nomral and shear forces and bending moments. The circumferential and radial normal stresses and shear stresses are obtained by the integration of equilibrium equations. Examples illustrate the developed method.

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