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A. Gontarz and G. Winiarski

Abstract

The paper presents the numerical and experimental results of a new method for producing flanges on hollow parts. With this new method, the flange is extruded by a movable sleeve. This innovative technique is modelled numerically by the finite element method. The effect of workpiece and finished product geometries on the forming process is investigated and failure modes are identfied. The numerical reults are then verified in experiments. The tests are conducted using a three-slide forging press equipped with a special device. The numerical and experimental results show a good agreement, which proves that the developed method is correct.

Open access

A. Gontarz, A. Dziubińska and Ł. Okoń

Determination of Friction Coefficients at Elevated Temperatures for Some Al, Mg and Ti Alloys

The results of research on friction conditions of alloys: magnesium Mg4AlZn, titanium Ti6Al4V and aluminum 6101A are presented in this paper. The aim of these research was determining values of friction factors and coefficients, which characterize constant friction model and Coulomb's model within the range of hot metal forming temperatures at various lubrication conditions. In the research works the ring tests were applied. For the alloy Mg4AlZn the samples were heated to the temperatures: 250°C, 350°C and 450°C, for aluminum alloy 6101A to the temperatures: 350°C, 400°C, 450°C and for alloy Ti6Al4V to the temperatures: 850°C, 900°C, 950°C. Tests were made in conditions of friction without lubrication and with the application of lubricants: tallow with graphite, Aquagraphite CP, Lubrodal-F318 and on the basis of molybdenum disulfide.

Friction factors and coefficients values were determined on the basis of comparison of experimental research results wih results of the conducted tests simulations. The value of factor and coefficient which guaranteed the best convergance of theoretical and experimental dimensions of upset samples was assumed as optimal. On the basis of the obtained results the influence of temperature on friction conditions and effectiveness of the used lubricants were determined in relation to analyzed alloys.

Open access

A. Gontarz, Z. Pater and K. Drozdowski

This paper presents the research results of hammer forging process of a plane wheel rim forging from titanium alloy Ti6Al4V. The research works were divided into two stages. The first concerned the theoretical analysis based on numerical simulations of the worked out forging technology. Distributions of temperature, strain, damage criterion according to Cockroft-Latham, material flow kinematics and force parameters were evaluated. It was stated that the danger of overheating and material cracking in the forging does not exist. Large force values present in the process means that problems with tools durability may appear. Satisfactory results of the theoretical analysis provided the basis for conducting the second stage of the research works, that is experimental tests in industrial conditions. After dies making forging tests were made in one Polish forging plants, in which a product of good quality was obtained. Manufactured forgings were free from cracks, shape faults and fulfilled requirements concerning mechanical properties.

Open access

A. Dziubińska, A. Gontarz and K. Dziedzic

Abstract

The paper reports a selection of numerical and experimental results of a new closed-die forging method for producing AZ31 magnesium alloy aircraft brackets with one rib. The numerical modelling of the new forming process was performed by the finite element method.The distributions of stresses, strains, temperature and forces were examined. The numerical results confirmed that the forgings produced by the new forming method are correct. For this reason, the new forming process was verified experimentally. The experimental results showed good agreement with the numerical results. The produced forgings of AZ31 magnesium alloy aircraft brackets with one rib were then subjected to qualitative tests.

Open access

A. Gontarz and G. Winiarski

The paper presents the numerical and experimental results of a new method for producing flanges on hollow parts. With this new method, the flange is extruded by a movable sleeve. This innovative technique is modelled numerically by the finite element method. The effect of workpiece and finished product geometries on the forming process is investigated and failure modes are identfied. The numerical reults are then verified in experiments. The tests are conducted using a three-slide forging press equipped with a special device. The numerical and experimental results show a good agreement, which proves that the developed method is correct.

Open access

G. Winiarski and A. Gontarz

Abstract

The paper presents a new metal forming process for producing two-step external flanges on hollow parts. With this method, the flange is extruded by a movable sleeve, which moves in the opposite direction to the punch. This reduces the phenomenon of buckling of the tube wall, which allows extruding flanges with relatively large volumes. The new method was applied to produce a two-step flange on the end of a tubular billet made of 6060 aluminum alloy. This cold metal forming process was designed based on numerical simulations and experimental tests. The effect of the basic technological parameters on metal flow was investigated and limitations of the process were identified. The experimental results confirmed the possibility of forming a two-step flange with a diameter that is approximately twice as big as the external diameter of the tubular billet.

Open access

R.E. Śliwa, T. Balawender, E. Hadasik, D. Kuc, A. Gontarz, A. Korbel and W. Bochniak

Abstract

The work presents an analysis of selected magnesium alloys as structural materials to be used in production of aircraft parts as well as their technological parameters in some manufacturing processes. Upsetting test, backward extrusion and Kobo extrusion of complex cross-sectional profiles and forging process were realized using magnesium alloys AZ31, AZ61, AZ80, WE 43 and Mg alloy with Li for production of thin - walled aircraft profiles and forged aviation parts. The range of temperatures and extrusion rate for the manufacturing these profiles were determined. Tests also covered the analysis of microstructure of Mg alloys in the initial state as well as after the extrusion process. It has been proved that the proper choice of parameters in the case of a specific profile extruded from magnesium alloys allows the manufacturing of products of complex cross-sections and the quality required in aerospace industry. This has been demonstrated on the examples of complex cross-sectional profiles using elements of varied wall thickness and examples of forged aviation parts: aircraft wheel hub and helicopter lever for control system.