Cold Backward Extrusion Research Articles

Processing Techniques and Metallurgical Perspectives and Their Potential Correlation in Aluminum Bottle Manufacturing for Sustainable Packaging Solutions

This study explores the potential of aluminum wine bottles as a sustainable alternative to traditional glass bottles, emphasizing their recyclability and environmental advantages. It reviews the potential use of Al-Mn-Mg 3xxx alloys in beverage can bodies and examines various applications of aluminum containers in packaging, including recyclable beverage containers. The manufacturing processes for aluminum bottles, including casting, rolling, punching, and deformation techniques, are discussed in detail, with a particular focus on their impact on mechanical properties and microstructure. The preference for 1xxx aluminum alloys in impact extrusion is explained, highlighting their lower flow stress and higher formability compared to 3xxx alloys, and the microstructural changes induced by various processing steps are analyzed. Challenges related to using recycled aluminum and their effects on mechanical properties and microstructure during aluminum bottle production are also addressed. One objective is to increase the proportion of recycled alloyed material used in aluminum bottle manufacturing. Depending on the technique employed, the fraction of alloyed recycled material can vary. The percentage of recycled alloyed material (3xxx series Al alloys) in cold backward impact extrusion could be raised by 60%. High-speed blow forming could facilitate the production of aluminum bottles with a recycled alloyed material ranging from 50 to 100% of the 3xxx series aluminum can body alloys. The high-speed drawing and ironing (DWI) process can produce large-format aluminum bottles (up to 750 mL), utilizing at least 90% of the recycled 3xxx series can body stock. Furthermore, the paper discusses the importance of optimized heat treatment designs in enhancing mechanical properties and controlling microstructural evolution in alloyed aluminum materials, such as 3xxx series alloys. The study concludes with a need for further research to deepen our understanding of the metallurgical aspects of aluminum bottle manufacturing and to optimize the use of recycled aluminum in packaging solutions, with a specific focus on improving mechanical properties and microstructural integrity. This comprehensive review aims to contribute to the development of more sustainable packaging practices in the beverage industry by providing insights into the interplay between manufacturing processes, mechanical properties, and microstructure of aluminum bottles.

Determination of Force and Pressure Functions for Backward Cold Extrusion of Aluminum Alloy 1350

A key indicator for the design of cold extrusion technology and materials is the force and pressure required to perform the process under different production conditions. Hence, this work is concerned with finding force and pressure functions of Aluminum 1350 for backward cold extrusion using regression method of experimental data. In order to find force and pressure functions considered, different mathematical formulas are used to obtain the optimum relations where several variables such as cavity diameter, semi-finished sizes, and extrusion strain are taken into account. Lack of data necessary for the calculation of the functions considered, depending on the different technological and construction parameters such as extrusion process, processed material, degree of deformation, form and dimensions of the part, semi-finished product and active elements of the molds requires the continuation of studies and research in this field. Analytical formulas, obtained using regression method, are considered essential for design and optimization purposes concerning backward extrusion for Aluminum 1350. Three different mathematical formulas have been developed for both pressure and force where good agreement has been found when compared to experimental records. Furthermore, cavity diameter and extrusion strain are found to be influential factors that affect the coefficients of force and pressure functions of cold backward extrusion.

Heat Transfer Coefficient of Zinc Phosphate Coating with Metal Soap during Cold Backward Extrusion

In cold forging, the temperature difference between the workpiece and the tool is small and thus deformation analysis is rarely coupled with thermal analysis. However, the friction coefficient of zinc phosphate coating with metal soap has a large temperature dependence. Consideration of the effects of workpiece and tool temperature change on the friction coefficient is thus expected to improve the analytical accuracy of cold forging. Thermally coupled cold forging analysis requires thermal conductivity, specific heat, heat transfer coefficient between the workpiece and the tool, in addition to the temperature dependence of flow stress and friction coefficient. The heat transfer coefficient between workpieces coated with zinc phosphate with metal soap and tools is investigated in this paper. Cold backward extrusion was performed with a 50% reduction of area, and the temperature history in the punch was measured with a thermocouple. The forging speed was 1, 3, and 10 spm. FEM analysis was performed to simulate the experiment by considering the temperature dependence of flow stress and friction coefficient. The heat transfer coefficient was estimated at 20 kW/(m2•°C) by comparing the experimental result and calibration curves.

Метод создания и расчет противодавления в экспериментах по холодному обратному выдавливанию магния

Метод создания и расчет противодавления в экспериментах по холодному обратному выдавливанию магния

Reduction in Axial Extrusion Load by Torsional Oscillation in Cold Backward Cup Extrusion

To reduce axial load in cold backward extrusion, torsional oscillation with a maximum frequency of 1.5 Hz around the extrusion axis was superposed with axial deformation. A cylindrical aluminum workpiece was simultaneously extruded in the axial direction and twisted in the circumferential direction between extrusion and knockout punches with a maximum axial speed of 0.1 mm/s, an alternating amplitude of 5°, and a maximum angular speed of 5 rpm at room temperature. The relationship between the torsional oscillation conditions and the axial load was investigated in backward extrusion with reductions in cross-sectional area of 0.17-0.69. The maximum reduction in axial load was obtained with approximately 20% in backward extrusion with a reduction in cross-sectional area of 0.51 under rotation/extrusion speeds higher than 60°/mm. The influence of the friction condition, the work-hardening characteristic of the workpiece, and the reduction in cross-sectional area on the reduction in axial load was discussed using the results of finite element simulation.

Maximum Reduction of Axial Load in Cold Backward Extrusion with Torsional Oscillation

Maximum Reduction of Axial Load in Cold Backward Extrusion with Torsional Oscillation

The analysis of distributions of effective strain and flow stress in longitudinal sections of cold backward extruded copper cans for different punch-face shapes

The paper presents computer modelling results of researches on cold backward extrusion of copper cans. The calculations were carried out using the commercial code QFORM-2D, based on the Finite Element Method (FEM). The simulation of cold backward extrusion process was performed for different punch-face shapes (flat; flat and conical with conical angle 900 and 1500; as well as concave). On the basis of obtained results, the analysis of distributions of effective strain and flow stress in longitudinal sections of cold backward extruded copper cans was conducted.

The Effect of Equivalent Strain on Punch Load for Cold Backward Extrusion of Copper Cans

The paper presents experimental and computer modelling (FEM) results of investigations into cold backward extrusion of copper cans. The simulations were performed using QFORM software based the finite element method (FEM). The samples used in investigations were pieces of copper rods having the diameter d0 = 24,5 mm and height h0 = 16 mm (h0/d0=0,65). The billets were heat treated (annealed). Heat treatment is used to increase the plasticity of the material before cold backward extrusion. The material was annealed at 550°C for a period of 1 h, and then subjected to solution treatment in water. The flat and conical punch-face shapes with different diameter of punch used for cold extrusion (ds=15mm; 16mm; 17mm; 19mm and 20mm, respectively). The deformation ratios of material in paper was defined as relative: strain of can bottom thickness εh =Δh/h0 (where Δh – the punch displacement, h0 – billet height), reduction in area εA= (A0-A1)/A0 and equivalent strain ε= ln (A0/A1) (where A0 – cross sectional area of the billet, A1 - cross sectional area of the die stamping). In investigations, computer calculated and experimental force waveforms as the function of displacement and εh were obtained. Comparing changes in forces in cold backward extrusion for different diameter of punch, it is stated that the load Pw increases with an increase in εh. The effect of equivalent strain ε on punch load Pw for cold backward extrusion of copper cans is presented. Both in experimental and modeling investigations, the axial force increased together with an increase in the equivalent strain.

Wpływ kształtu stempla na siłę nacisku przy wyciskaniu na zimno wyprasek w kształcie naczyń cylindrycznych z miedzi

Wpływ kształtu stempla na siłę nacisku przy wyciskaniu na zimno wyprasek w kształcie naczyń cylindrycznych z miedzi

The Influence of Extrusion Ratio on Contact Stresses and Die Elastic Deformations in the Case of Cold Backward Extrusion

In this paper, the distribution of contact stresses along the die-workpiece interface as well as elastic deformation behavior of the die in the cold backward extrusion of steel billets have been investigated both experimentally and numerically. For the experiments, a special tooling set including a pin load cell measuring device was designed and made. Contact stresses were recorded at various points in time and at various locations during the extrusion process, i.e. for different punch strokes (part’s bottom thickness). The research focus was on determining the extrusion ratio’s influence on the distribution of the contact stresses and therefore the experiments were performed using five punches of different head diameters. In the next step, based on the measured contact stresses, radial displacements of the inner die wall were calculated by applying Lame’s equation. Furthermore, an extended finite element analysis of the investigated extrusion process was carried out using Simufact.forming software. The results of numerical simulations for the contact stresses were compared with experiments. The benefits and weaknesses of the pin load cell measuring technique and Lame’s formula when it is employed for determination of the die elastic deformation were also examined, as well as were the contribution of the die elastic deformation to dimensional errors of the extruded parts.

Evaluation of the Possibility of Performing Cold Backward Extrusion of Axisymmetrical Thinwalled Aluminum Die Stampings with Square Section / Ocena Możliwości Wyciskania Przeciwbieżnego Na Zimno Osiowosymetrycznych Wyprasek Z Cienką Ścianką O Przekroju Kwadratowym Z Aluminium

The paper presents evaluation of the possibility of performing cold backward extrusion of axisymmetrical thin-walled aluminum (Al 99.50, ENAW-1050A) die stampings with a square section at the strain ε=ln(A0/A1)=2 (where A0 - cross sectional area of the billet, A1 - cross sectional area of the die stamping), and the ratio h1/b=3.6 (where h1 - height of the die stamping in mm, b - width of the base of the die stamping in mm). The analysis was conducted on the basis of the results of computer modelling (FEM) and experimental investigations on backward extrusion. The boundary conditions for numerical calculations were determined experimentally with respect to the flow curve and mechanical properties of aluminum. The results of investigations into backward extrusion of thin-walled square-sectioned aluminum die stampings might be used as guidelines to develop a technological process for industrial practice.

Study on the deformation behavior of polyamide under the backward extrusion process

Abstract This study explores the deformation behavior of polyamide in the process of backward extrusion at room temperature by both finite element (FE) and design of experiment (DOE) procedures. The distributions of effective strain through the length and the thickness of processed polyamide tube by cold backward extrusion are investigated and compared with ductile metals. The die parameters are comprised of slope angle, corner radius of punch and container which are selected as input parameters. The Taguchi DOE approach is exploited in order to decrease repeated simulations, after which 16 results are carried out. Analysis of variance is performed on simulation results, and it is proved that the corner radius of punch has the greatest effect among die parameters in the mentioned process, in reducing the processing load. The influence of this parameter is obtained as 98%. Eventually, the optimum condition is proposed. Also, the deformation behavior and the probability of failure based on the normalized Cockroft-Latham criterion are studied under this condition.

Influence of Processing Parameters on Bonding Conditions in Backward Extrusion Forged Bonding

In this study, conditions of metallurgical bonding between steel and aluminum in cold forging process is investigated. Two-layered cylindrical cup of the materials is produced in cold backward extrusion in five processing velocity conditions. Small tensile test specimens are cut off at the bonding boundary in the product using a wire-cutting machine and the bonding strength on the boundary is measured in tensile test using the specimens. Fractured contact surfaces are observed with an electron microscope for investigation of bonding. Finite element analyses for the backward extrusion are conducted and surface expansion ratio and interface pressure on the boundary are calculated. The influence of process conditions, extrusion velocity and surface expansion ratio and boundary pressure, on the bonding are investigated.

Cold Backward Extrusion of Titanium Billet with Pulsating Lubricant Supply on Servo Press

To prevent seizure in backward extrusion of holes for lightweight structural components, an extrusion method utilizing a punch having an internal channel for supplying liquid lubricant to the punch nose was applied to forming of pure titanium billet using a servo press. On the servo press, the punch was pushed into the billet in a manner combining pulsed and stepwise modes. The sufficient amount of the liquid lubricant was pulsating supplied to the cavity formed at the bottom of the hole. Appropriate punch ram motion and forming limit for preventing seizure are determined from the surface observation of the formed hole and the punch.

鋼板の精密穴抜き加工におけるPWパンチの耐焼付き性評価

In piercing, a smooth shearing surface can be obtained by reducing the clearance between the punch and the die. However, continuous piercing in a small clearance is difficult during mass production, since adhesion may easily occur. A Press Working punch (PW punch) is a punch for piercing a steel plate developed on the basis of cold backward extrusion technology. However, the dimensions of the PW punch were not evaluated accurately. In this study, we evaluated the adhesion resistance of the PW punch when used for the fine piercing of a steel plate. Experiments on continuous piercing using a PW punch with a 10 mm diameter and 0.5 % clearance are performed on a hot-rolled steel plate having a thickness of 4.5 mm. Experiments using a conventional right angle punch are also performed for comparison. A mirrorlike shearing surface was obtained using a ceramic-coated PW punch without causing adhesion in 600 continuous piercings. As a result, the PW punch was found to be highly advantageous for the piercing of steel plates.

Improvement of Forgeability of a Commercial AZ31B Magnesium Alloy in Cold Backward Extrusion with Counter Pressure

In order to improve the forgeability of a commercial wrought AZ31B magnesium alloy (Mg-3%Al-1%Zn) at room temperature, backward extrusion is carried out with applying counter pressure. A counter pressure is applied from a die exit of backward extrusion. By applying counter pressures of 100–200 MPa during backward extrusion, the critical punch stroke for fracturing is improved by 20% because the ductility increases under a high pressure. To predict the occurrence of fracturing of magnesium alloys, the distributions of the stress, strain and temperature during forging are calculated by the finite element simulation because the existing fracture criteria are not adequate to predict the occurrence of fracturing of magnesium alloys in forging. The mechanism of fracturing is discussed on the basis of plastic deformation, and a fracture criterion of magnesium alloy in cold forging is suggested. The newly proposed criterion provides much better results than the existing criteria. [doi:10.2320/matertrans.MC200710]

Fracture of Magnesium Alloy in Cold Forging

In order to clarify the forming limit of magnesium alloy in cold forging, the workability of magnesium alloy AZ31B (Mg-3%Al-1%Zn) is examined by upsetting and backward extrusion. In the upsettability test, shear type fracture occurs at a small equivalent strain of about 0.15 at temperatures lower than 170 °C. At a higher temperature, the flow stress curve has a peak at an average equivalent strain of 0.2–0.3, showing a clear tendency to work soften. In cold backward extrusion with a conical punch, the local strain can reach a very large value, 3.0 or greater, without fracture. To explain the experimental results, the mechanism of fracturing is discussed on the basis of strain localization, and a fracture criterion of magnesium alloy in cold forging is suggested. The newly proposed criterion provides much better results than the existing criteria.

A design method for cold backward extrusion using FE analysis

The dimensional accuracy of the cold forged products is strongly dependent on the elastic characteristics of the die. Therefore, a design method that makes the elastic deformation of the prestressed die as small as possible has been proposed for precision cold forging. For the purpose, applying the hard materials such as sintered carbide to the first stress ring is considered in die construction. For the design, Lamé's equation is used and the diameter ratios and interferences are determined by using the maximum inner pressure without yielding of rings after shrink fitting and during cold forging. The rigid-plastic FE analysis of backward extrusion process using DEFORM has been performed and the analysis of elastic deformation of the dies has been done by using ANSYS with non-linear contact. In the simulation results, it has been found that the use of high stiffness materials to the first stress ring of forging dies can reduce the elastic deformation of die insert without failure.

Prediction of Dimensional Difference of Product from Tool in Cold Backward Extrusion

The effects of forming stresses and generated heat on the dimensional change of punch, die and work piece during forging are discussed analytically. The change in outer and inner diameter of backward extruded cup is investigated numerically using thermo-elastic-plastic FEM code according to the actual forging sequence, namely extruding, unloading of punch force, and ejection and air cooling of extruded cup. The calculated results of outer and inner diameters of product are in good agreement with the experimental results. The simulation can be used to determine the initial tool dimensions for precision parts in the tool design process of cold forging.

Influence of different friction conditions on the process of cold backward extrusion of steel

Backward extrusion of steel is a deformation process in which very high forces and tool pressures occur. Reduction of such high forces and tool pressures is possible by using an efficient lubricant. This paper describes an experimental investigation of the influence of different lubricants on the stress-strain state within the workpiece volume as well as on the stressing of the die. Best results were obtained when a phosphate-coated specimen was lubricated with MoS2.