The article covers experimental research on the forming of products made of 7075 aluminum alloy. This aluminum alloy grade is characterized by high strength, but due to its low formability in T6 temper, its use in the stamping processes of complex structural elements is limited. The authors have manufactured a U-shaped element at an elevated temperature and determined the optimal parameters of the process. Conventional heating of the sheet and shaping it at the temperature of 100 and 150 °C allowed to obtain a product of high strength similar to the T6 state, above 540 MPa. Due to the excessive springback of the sheet during forming, these products were characterized by a large deviation of the shape geometry, exceeding the allowable values of + / − 1 mm. Only the use of an alternative method of heating the sheet to temperatures of 200 and 240 °C (between plates at 350 °C, heating time 2 min, heating rate 1.8 °C/s) allowed to obtain a product that meets both the strength and geometric requirements. The determined optimal process’ parameters were later transferred to the stamping process of elements of a more complex shape (lower part of the B-pillar). The sheet was heated up and formed in the previously pre-heated tools. In the subsequent series of tests, the heating method and the blank’s temperature were being analyzed. In the case of the foot of the B-pillar, it was necessary to lower the initial blank temperature to 200 °C (heating in a furnace with a temperature of 340 °C, heating speed 0.5 °C/s). The appropriate combination of the process parameters resulted in the satisfactory shape deviation and reaching the product’s strength comparable to the strength of the material in as-delivered T6 temper. Using electron microscopy, it was verified that the structure of the finished product contained particles MgZn₂ that strongly strengthen the alloy. The obtained results complement the data on the possibility of using 7075 aluminum alloy to produce energy-absorbing elements of motor vehicles.

The purpose of the work was to test the welded joints of aluminum alloys EN AW-7075 and EN AW-6082, which are used to join individual structural elements of car bodies, e.g., B-pillar with the body. The joints were made using the low-energy cold metal transfer (CMT) arc welding method. The results of the structure investigations of lap and butt joints, as well as tests of mechanical properties are presented. The influence of linear energy and the way of arranging materials in lap joints on the possibility of hot cracks occurrence has been demonstrated. The shear strength of lap joints was equal to 150 MPa, while the tensile strength of butt joints was equal to 375 MPa. The highest hardness reduction was observed in the heat affected zone (HAZ) from the EN AW-7075 alloy side in the range of 98 to 138 HV 0.05. In addition, a significant reduction of the corrosion resistance in the transition zone between HAZ and the base material (EN AW-7075 alloy) in the medium salinity environment, corresponding to the sea conditions according to ASTM G85 was indicated.

The global production of die forgings is an important branch of the motor industry for obvious reasons, resulting from the very good mechanical properties of the forged products. The expectations of the recipients, beside the implementation of the forging process, include also a range of supplementary procedures, such as finishing treatment including shot blasting, thermal treatment, and machining, in order to ensure the proper quality of the provided semi-product or the ready detail for the assembly line. Especially important in the aspect of the operational properties of the products is the thermal treatment of the forgings, which can be implemented in many variants, depending on the expected results. Unfortunately, a treatment of this type, realized separately after the forging process, is very time and energy-consuming; additionally, it significantly raises the production costs due to the increased energy consumption resulting from the necessity of repeated heating of the forgings for such thermal treatment. The article reviews the most frequently applied (separately, after the forging process) thermal treatments for die forgings together with the devices/lines assigned for them, as well as presents an alternative (thermoplastic) method of forging production with the use of the forging heat. The paper also presents a prototype semi-industrial controlled cooling line developed by the authors, which allows the development of the assumed heat treatment of forgings directly after forging with the use of forging heat, together with sample results of conducted tests.

This article presents a study on symmetric cyclic torsion with the application of electric pulses and their effect on the formability of α-brass CuZn30 at room temperature. Preliminary tests were carried out using a conventional monotonic torsion test. The obtained results served as a reference for the subsequently conducted symmetric cyclic torsion tests. Then, under analogical deformation conditions, tests were conducted with the application of electric pulses featuring various parameters: different pulse durations and different periods, i.e., intervals between successive pulses. Microstructural studies of the deformed material were conducted, including examinations using a microscope equipped with an electron backscatter diffraction (EBSD) detector. Based on the results, it was found that the application of electric pulses during cyclic torsion tests consistently leads to a reduction in stress compared to cyclic torsion tests conducted at ambient temperature without current flow. In most cases, it also results in an increase in strain compared to tests without the application of electric pulses. The electroplastometric torsion tests carried out in this study within the bulk forming process are the first of their kind to combine cyclic torsion with electrically assisted forming (EAF). The proposed combination may lead to the development of new deformation methods in real manufacturing processes.

This article presents the results of research on electrically assisted forming (EAF) in the process of cyclic oscillatory torsion of CuZn30 brass. Experiments were conducted using pulsed electric current with varying parameters: pulse durations of 0.5, 2.5, and 5 ms, and pulse intervals ranging from 0.5 to 30 ms. Reference data for the electrically assisted torsion tests were obtained from conventional tests performed under identical conditions without current flow. A pronounced thermal effect was observed for specific current parameters. To accurately determine the impact of temperature rise on the deformability of CuZn30 brass during cyclic torsion, the authors conducted additional tests at elevated temperatures—corresponding to the average temperatures recorded during the EAF trials—without current application. In all investigated cases, EAF during cyclic oscillatory torsion led to a flow stress reduction ranging from nearly 8% to almost 25% compared to current-free trials. Furthermore, applying current parameters where the pulse interval exceeded the pulse duration resulted in a significant increase in strain to failure, ranging from nearly 25% up to 110% relative to the reference samples. The study also examined isophase current characteristics (where pulse duration equals pulse interval), which yielded results that clearly deviated from other configurations. The application of isophase pulses triggered a different material response, leading to a degradation of deformability by more than 21%. The presented research and findings may contribute to the further development of novel, energy-efficient, and advanced manufacturing processes in metal forming.