Predictive Tools for in-Line Isothermal Extrusion of 6xxx Aluminum Alloys

During the last fifty years, the metal forming of aluminum alloys advanced significantly, leading to a more competitive market on which production rate and overall quality are kept as high as possible. Within the aluminum industries, extrusion plays an important role, since many industrial products with structural or even aesthetic functions are realized with this technology. Especially in the automotive industry, the use of aluminum alloys is growing very fast, since it permits a considerable weight loss and thus a reduction of the emission. Nevertheless, the stringent quality standards required don’t allow the use of extruded aluminum alloys produced for common building applications. An important parameter that can be used as an index of the quality of the extruded product is the emergent temperature: if the temperature at the exit of the press is kept constant within a certain limit, products with homogeneous properties and high-quality surface are obtained and the so called “isothermal extrusion” is achieved. As extrusion industries are spread all over the world with different levels of automation and control, a universal but simple on-line tool for determining the best process condition to achieve isothermal extrusion is of particular interest. The aim of this work is to implement this model, which allows evaluation of the thermal gradient which has to be imposed on the billet. Several experiments have been carried out on an industrial extrusion press, and the outer temperature was recorded and compared with the simulated one to demonstrate the model consistency.

Mathematical simulation of seamless pipes extrusion and rational calibration of die

Technology of seamless pipes production by extrusion enables to deform pipe workpieces made of low-plastic materials. However, low durability of the working instrument restricts the area of the technology application. The purpose of the work was to specify optimal parameters of technological processes of pipes extrusion. Minimization of energy and force parameters of the deformation zone and an increase of once-only metal deformation were accepted as criteria. They will enable to increase the presses productivity, increase durability of working instrument and accuracy of pipes geometric dimensions. A mathematical model of deformation zone and stressed state of pipe workpiece were elaborated. Influence of the die generatrix calibration and deformation zone parameters on the character of energy and force parameters change revealed. Dependence of energy and force parameters on the die calibration and geometric parameters of deformation zone for the press 50 MH was established. The results of mathematical simulation of pipes extrusion showed that along the whole deformation zone length, increase of metal flow speed results in an increase of tangential and normal stresses on the forming mandrel and calibrated die. The task of parametric optimization of die profile (calibration) was accomplished in interpretation of base variation Euler’s task for a determined functional of pipes extrusion. It was established that while the extrusion speed is increasing, the energy and force parameters of the deformation zone are getting pronounced dynamic character. At that, by optimization of die calibration, an increase of the extrusion press 50MH working instruments durability was reached, as follows: dies – by two times, mandrels – by 4 times, container bushes – by 40% and press-washers – by 2 times.

In-Depth Comparison of an Industrially Extruded Powder and Ingot Al Alloys

An industrial press was used to consolidate compacted aluminum powder with a nominal diameter in the range of 1 µm. Direct and indirect hot-extrusion processes were used, and suitable process parameters were determined from heating conditions, ram speeds and billet temperatures. For comparison, a direct-extrusion press for hot extrusion of a conventional aluminum alloy AA 1050 was used. The extruded Al powder showed better mechanical properties and showed a thermal stability of the mechanical properties after annealing treatments. To increase the theoretical density of the directly extruded Al powder, single-hit hot-compression tests were carried out. Activation energies for hot forming were calculated from hot-compression tests carried out in the temperature range 300–580 °C, at different strain rates. Processing maps were used to demonstrate safe hot-working conditions, to obtain an optimal microstructure after hot forming of extruded Al powder.

Analysis of the Possibility of Obtaining Aviation Profiles from 7039 Aluminum Alloy in the Extrusion Process

This article presents the process of extrusion shape of complex geometry cross-sectional 7039 aluminum alloy for use in aerospace industry. This study aims to characterize the properties of aluminum alloy as structural material and to determine the technological parameters of the indirect extrusion press and their influence on mechanical properties and the microstructure of the final product. It has been proved that the proper choice of parameters in the case of a specific profile extruded from 7039 aluminum alloy allows the manufacturing of products of complex cross-sections and the quality required in aerospace industry.

Analysis of possibilities for manufacturing of largesized powder parts of cup type on extrusion press with actively directed contact friction stresses

Two options for manufacturing parts of the cup type from iron powders, which differ in the sequence of pressing operations of the billet and its sintering is compared. The possibility of combining both of these technology options in the one technological process is considered. According to the transitions of forming workpiece on the created press with force of 6.3 MN the implementation of such technological process for the production of part with mass of 4 kg 790 g is considered.

A Numerical Study on Co-Extrusion to Produce Coaxial Aluminum-Steel Compounds with Longitudinal Weld Seams

The use of lightweight materials is one possibility to limit the weight of vehicles and to reduce CO2 emissions. However, the mechanical properties and weight-saving potential of mono-materials are limited. Material compounds can overcome this challenge by combining the advantages of different materials in one component. Lateral angular co-extrusion (LACE) allows the production of coaxial semi-finished products consisting of aluminum and steel. In this study, a finite element model of the LACE process was built up and validated by experimental investigations. A high degree of agreement between the calculated and experimentally determined forces, temperatures, and the geometrical shape of the hybrid profiles was achieved. In order to determine suitable parameters for further extrusion experiments, the influence of different process parameters on material flow and extrusion force was investigated in a numerical parametric study. Both the temperature and extrusion ratio showed a significant influence on the occurring maximum extrusion force as well as the material flow inside the LACE tool. The maximum force of 2.5 MN of the employed extrusion press was not exceeded. An uneven material flow was observed in the welding chamber, leading to an asymmetric position of the steel rod in the aluminum matrix.