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1
Content available Prediction of Waviness Values in Skew Rolling Using Machine Learning Methods
Lis Konrad, Pater Zbigniew, Tomczak Janusz, Bulzak Tomasz Adam, Kusiak Tomasz
Advances in Science and Technology. Research Journal
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2023
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Vol. 17, no 5
350--359
EN
Skew rolling with three rolls is used for producing axisymmetric parts. In this method, the tools are spaced every 120° on the circumference of the workpiece. They are also set askew relative to the rolling axis. Cross sectional reduction is made effective by moving the tapered rolls closer to or away from the center line of the workpiece. Experiments were conducted with variable initial conditions of the rolling process to examine surface topography of rolled parts. Obtained experimental results were then analyzed using machine learning methods in order to determine the most effective regression model with the highest coefficient of determination R2 for waviness prediction.
2
Content available Multi-Variant Analysis of the Cross Wedge Rolling Process for Producing Railcar Axles
Pater Zbigniew, Tomczak Janusz, Bulzak Tomasz Adam
Advances in Science and Technology. Research Journal
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2023
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Vol. 17, no 5
208--219
EN
This study investigates the cross wedge rolling (CWR) process for manufacturing a rail axle in a scale of 1:6. Three cases of the rolling process are modelled numerically: standard rolling, wasteless rolling and rolling from a preform. The rolling cases under analysis are compared in terms of material and energy consumption, forming loads as well as propensity to internal and external defect formation. Using the Cockcroft-Latham criterion and the limits of this criterion determined by the rotary compression test, an assessment was made of the propensity of the material to fracture during the rolling processes analysed. Based on numerical results, standard CWR is selected for experimental verification. Obtained experimental results confirm that CWR is an effective method for producing railcar axles that are free from both internal and external defects. The experimental and numerical results obtained confirm that cross wedge rolling technology can be successfully used under industrial conditions for the production of long axles or shafts.
3
Content available Numerical Analysis of a Six Stage Forging Process for Producing Hollow Flanged Parts from Tubular Blanks
Winiarski Grzegorz, Bulzak Tomasz Adam, Wójcik Łukasz, Szala Mirosław
Advances in Science and Technology. Research Journal
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2020
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Vol. 14, no 1
201--208
EN
This paper presents the results of a numerical analysis of a cold forging process for a hollow flanged part. The analysis was performed using Deform 2D/3D. 42CrMo4 steel tubes were used as the billet material, and their material model in the annealed state was described by a constitutive equation. The forming process was performed in six stages with the use of methods such as extrusion with a movable sleeve, open-die extrusion, and upsetting. The objective of the study was to determine whether the proposed forging technique could be used to produce hollow parts with flanges. The determination was made based on the analysis of product geometry quality and process parameters, including the Cockcroft-Latham ductile fracture criterion and forming forces.
4
Content available A New Method of Flanges Extrusion in Hollow Products – Analysis of the Limiting Phenomena
Winiarski Grzegorz, Bulzak Tomasz Adam, Wójcik Łukasz, Szala Mirosław
Advances in Science and Technology. Research Journal
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2020
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Vol. 14, no 4
78--85
EN
The paper presents an innovative method of metal forming of hollow flanged elements. In this process, flanges are formed using a movable sleeve, which moves in the opposite direction to the punch. The movement of the sleeve causes a closed impression to open, due to which the flange is also formed in a semi-free impression. The tube billets were made of the 42CrMo4 grade steel deformed under the cold metal forming conditions. The calculations were conducted using the finite elements method in Deform-2D/3D. Various technological parameters of the process were analysed, among others the diameter of the flange and the initial height of the impression of the movable sleeve. On the basis of the obtained results, the limiting phenomena of the process were determined and the influence of the analysed technological parameters on these phenomena were presented.
5
Content available Effect of Tool Kinematics on Tube Flanging by Extrusion with a Moving Sleeve
Winiarski Grzegorz, Bulzak Tomasz Adam, Wójcik Łukasz, Szala Mirosław
Advances in Science and Technology. Research Journal
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2019
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Vol. 13, no 3
210--216
EN
This paper presents the results of a numerical investigation into tube flanging by extrusion with a moving sleeve. Two cases of the extrusion process are investigated, each described with a different tool kinematics. Effects of flange diameter, gap height and tool motion on the extrusion process are examined. The numerical analysis is performed on 42CrMo4 steel tubes deformed at ambient temperature. Obtained numerical results are then used to determine metal flow patterns and examine force parameters in the extrusion process, as well as to determine a technological window for the investigated method.
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