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Challenges and Achievements in Metal Forming

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A special issue of Metals (ISSN 2075-4701). This special issue belongs to the section "Metal Casting, Forming and Heat Treatment".

Deadline for manuscript submissions: closed (31 January 2021) | Viewed by 51423

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Special Issue Editors

Dr. Gabriela Vincze

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Department of Mechanical Engineering, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal
Interests: microstructure/property relationships; plasticity; formability; crystallographic texture and constitutive modeling
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Dr. Marilena Butuc

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Department of Mechanical Engineering, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal
Interests: plasticity; formability; constitutive modeling; fracture; advanced high strength steels; aluminum alloys
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Assoc. Prof. Tudor Balan

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Arts et Métiers ParisTech – Metz Campus, 4 rue Augustin Fresnel, 57078 Metz Cedex 03, France
Interests: metal forming; constitutive modeling; plastic anisotropy; springback; process simulation

Special Issue Information

Dear Colleagues,

The continuous development of high-quality products, including mechanical properties, design and their impact on the environment, while at the same time maintaining a competitive price is a challenging task for all industrial production.

The quality of products depends strongly on the material properties, processing conditions and their behavior in service conditions. The mechanical properties are determined by chemical composition, precipitation state, strain hardening and crystallographic texture. Moreover, large strains and complex strain-paths are induced by the forming processes in order to achieve more and more challenging final shapes. As a consequence, undesirable effects arise, such as distortions due to the springback, softening, earlier plastic instability, fractures, etc. These effects are consequences of the material structure and process conditions, and are possible to control by a deep understanding of the process–structure relationship.

This Special Issue aims to present state-of-the-art research results related to several aspects of metal forming processes, taking into consideration all the factors involved, from the material structure to industrial applications. Full papers, communications and reviews are welcome.

Dr. Gabriela Vincze
Dr. Marilena Butuc
Assoc. Prof. Tudor Balan
Guest Editors

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Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Metals is an international peer-reviewed open access monthly journal published by MDPI.

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Keywords

Springback
Plasticity
Fracture
Microstructure
Texture
Mechanical behavior
Modelling
Numerical simulation
Experimental mechanics

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Published Papers (13 papers)

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Research

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14 pages, 4318 KiB

Open AccessArticle

Control-Oriented Characterization of Product Properties during Hot Hole-Flanging of X46Cr13 Sheet Material in a Progressive-Die

by Juri Martschin, Rickmer Meya, Daniel Klöser, Thomas Meurer and A. Erman Tekkaya

Metals 2021, 11(2), 349; https://doi.org/10.3390/met11020349 - 19 Feb 2021

Cited by 2 | Viewed by 3590

Abstract

Robust and versatile production is enabled by a closed-loop control of product properties. This essentially relies on the characterization of the interaction between properties and available degrees of freedom to control the process. In particular, this work examines the setting of collar height, thinning, curvature, and hardness during hot hole-flanging of X46Cr13 sheet material with simultaneous heat treatment to identify approaches for a closed-loop property control in hot hole-flanging during multi-stage hot sheet metal forming. To scrutinize the adjustability of the hardness of X46Cr13 sheet material by heat treatment with rapid heating and short dwell times, quenching tests with austenitizing temperatures from 900 to 1100 °C and dwell times from 1 to 300 s were carried out. A hardness between 317 and 680 HV10 was measured. By analyzing the force-displacement curve and the contact situation between tools and blank during hot hole-flanging, an understanding for the process was established. To determine the adjustability of geometrical collar properties and the hardness of the collar, collars were formed at punch speeds between 5 and 100 mm/s and at different temperatures. Here, a dependency of the geometry of the collar on temperature and punch speed as well as setting of the hardness was demonstrated. Full article

(This article belongs to the Special Issue Challenges and Achievements in Metal Forming)

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16 pages, 24374 KiB

Open AccessFeature PaperArticle

Increasing the Lightweight Potential of Composite Cold Forging by Utilizing Magnesium and Granular Cores

by Robin Gitschel, Felix Kolpak, Oliver Hering and A. Erman Tekkaya

Metals 2021, 11(1), 32; https://doi.org/10.3390/met11010032 - 26 Dec 2020

Cited by 3 | Viewed by 3176

Abstract

In this paper a process sequence, that uses forward rod extrusion with cold forged C15 steel cup billets to produce lightweight shafts, is presented. The steel cup billets feature either a lightweight magnesium alloy core or a granular medium core that is removed after forming to obtain hollow shafts without the need of complex tools and highly loaded mandrels. It is shown that composite shafts featuring magnesium cores can be produced for a wide range of extrusion strains. Due to high hydrostic pressures in forward rod extrusion, the forming limit of magnesium at room temperature can be expanded. The observed bond strength between core and sheath is below the shear yield strength of utilized magnesium AZ31 alloy. Hollow shafts are successfully produced with the presented process route by utilizing zirconium oxide beads or quartz sand as a lost core. As the law of constant volume in metal forming is violated by compressible granular media, a simulation approach using a modified Drucker-Prager yield surface to model these materials is validated to provide a tool for efficient process design. Granular cores and magnesium alloy cores offer new possibilities in production of lightweight shafts by means of composite cold forging. Both process variants allow for higher weight savings than composite shafts based on aluminum cores. Full article

(This article belongs to the Special Issue Challenges and Achievements in Metal Forming)

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17 pages, 10239 KiB

Open AccessArticle

Experimental and Numerical Study of the Effects of the Reversal Hot Rolling Conditions on the Recrystallization Behavior of Austenite Model Alloys

by Krzysztof Muszka, Mateusz Sitko, Paulina Lisiecka-Graca, Thomas Simm, Eric Palmiere, Matthias Schmidtchen, Grzegorz Korpala, Jiangting Wang and Lukasz Madej

Metals 2021, 11(1), 26; https://doi.org/10.3390/met11010026 - 25 Dec 2020

Cited by 1 | Viewed by 2576

Abstract

The experimental and numerical study of the effects of the recrystallization behavior of austenite model alloys during hot plate rolling on reverse rolling is the main goal of the paper. The computer models that are currently applied for simulation of reverse rolling are not strain-path-sensitive, thus leading to overestimation of the processing parameters outside the accepted process window (e.g., deformation in the partial austenite recrystallization region). Therefore, in this work, a particular focus is put on the investigation of strain path effects that occur during hot rolling and their influence on the microstructure evolution and mechanical properties of microalloyed austenite. Both experimental and numerical techniques are employed in this study, taking advantage of the integrated computational material engineering concept. The combined isotropic–kinematic hardening model is used for the macroscale predictions to take into account softening effects due to strain reversal. The macroscale model is additionally enriched with the full-field microstructure evolution model within the cellular automata framework. Examples of obtained results, highlighting the role of the strain reversal on the microstructural response, are presented within the paper. The combination of the physical simulation of austenitic model alloys and computer modeling provided new insights into optimization of the processing routes of advanced high-strength steels (AHSS). Full article

(This article belongs to the Special Issue Challenges and Achievements in Metal Forming)

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23 pages, 9841 KiB

Open AccessFeature PaperArticle

Issues on the Correlation between Experimental and Numerical Results in Sheet Metal Forming Benchmarks

by Rui L. Amaral, Diogo M. Neto, Dipak Wagre, Abel D. Santos and Marta C. Oliveira

Metals 2020, 10(12), 1595; https://doi.org/10.3390/met10121595 - 28 Nov 2020

Cited by 2 | Viewed by 2638

Abstract

The validation of numerical models requires the comparison between numerical and experimental results, which has led to the development of benchmark tests in order to achieve a wider participation. In the sheet metal-forming research field, the benchmarks proposed by the Numisheet conference series are a reference, because they always represented a challenge for the numerical codes within the state of the art in the modeling of sheet metal forming. From the challenges proposed along the series of Numisheet benchmarks, the springback prediction has been frequently incorporated, and is still a motivation for the development and testing of accurate modeling strategies. In fact, springback prediction poses many challenges, because it is strongly influenced by numerical parameters such as the type, order, and integration scheme of the finite elements adopted, as well as the shape and size of the finite element mesh, in addition to the constitutive model. Moreover, its measurement also requires the definition of a fixture that should not influence the actual springback and the proper definition of the measurement locations and directions. This is the subject of this contribution, which analyzes the benchmark focused on springback prediction, proposed by the Numisheet 2016 committee. Numerical results are obtained with two different codes and comparisons are performed between both numerical and experimental data. The differences between numerical results are mainly dictated by the ambiguous definition of boundary conditions. The analysis of numerical and experimental springback results should rely on the use of global planes to ensure the objectivity and simplicity in the comparison. Therefore, the analysis gives an insight into issues related to the comparison of results in complex geometries involving springback, which in turn suggests some recommendations for similar future benchmarks. Full article

(This article belongs to the Special Issue Challenges and Achievements in Metal Forming)

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25 pages, 14001 KiB

Open AccessArticle

Analysis of Forming Behavior in Cold Forging of AISI 1010 Steel Using Artificial Neural Network

by Praveenkumar M. Petkar, V. N. Gaitonde, S. R. Karnik, Vinayak N. Kulkarni, T. K. G. Raju and J. Paulo Davim

Metals 2020, 10(11), 1431; https://doi.org/10.3390/met10111431 - 28 Oct 2020

Cited by 8 | Viewed by 3765

Abstract

Cold forged parts are mainly employed in automotive and aerospace assemblies, and strength plays an essential role in such applications. Backward extrusion is one such process in cold forging for the production of axisymmetrical cup-like parts, which is affected by a number of variables that influence the quality of the products. The study on the influencing parameters becomes necessary as the complexity of the part increases. The present paper focuses on the use of a multi-layered feed forward artificial neural network (ANN) model for determining the effects of process parameters such as billet size, reduction ratio, punch angle, and land height on forming behavior, namely, effective stress, strain, strain rate, and punch force in a cold forging backward extrusion process for AISI 1010 steel. Full factorial design (FFD) has been employed to plan the finite element (FE) simulations and accordingly, the input variables and response patterns are obtained for training from these FE simulations. This ANN model-based analysis reveals that the forming behavior of the cold forging backward extrusion process tends to increase with the billet size as well as the reduction ratios. However, decreases in punch angle and land height lead to the reduction of punch forces, which in turn enhances the punch life. FE simulation along with the developed ANN model scheme would benefit the cold forging industry in minimizing the process development effort in terms of cost and time. Full article

(This article belongs to the Special Issue Challenges and Achievements in Metal Forming)

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18 pages, 3659 KiB

Open AccessFeature PaperArticle

Development of a Nakazima Test Suitable for Determining the Formability of Ultra-Thin Copper Sheets

by Nejia Ayachi, Noamen Guermazi, Cong Hanh Pham and Pierre-Yves Manach

Metals 2020, 10(9), 1163; https://doi.org/10.3390/met10091163 - 28 Aug 2020

Cited by 13 | Viewed by 6451

Abstract

The objective is to propose an accurate method for determining the forming limit curves (FLC) for ultra-thin metal sheets which are complex to obtain with conventional techniques. Nakazima tests are carried out to generate the FLCs of a pure copper and a copper beryllium alloy with a thickness of 0.1 mm. Because of the very small thickness of the sheets, the standard devices and the know-how of this test are no longer valid. Consequently, new tools have been designed in order to limit friction effect. Two different methods are used and compared to estimate the necking: the position-dependent measurement method (ISO Standard 12004-2), and the time-dependent method based on the analysis of the derivatives of the planar strain field. It is shown that the ISO standard method underestimates the forming limit curves. As the results present non linear strain paths, a compensation method is applied to correct the FLCs for the tested materials, which combines the effects of curvature, nonlinear strain paths and pressure. The curvature effect for such thickness and punch diameter on the FLCs is weak. The results show that this procedure enables to obtain FLCs that are close to those determined by the reference Marciniak method, leading to a minimum in major strain that converges to the plane strain state. Full article

(This article belongs to the Special Issue Challenges and Achievements in Metal Forming)

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18 pages, 5569 KiB

Open AccessArticle

Numerical Prediction and Reduction of Hat-Shaped Part Springback Made of Dual-Phase AHSS Steel

by Peter Mulidrán, Emil Spišák, Miroslav Tomáš, Ján Slota and Janka Majerníková

Metals 2020, 10(9), 1119; https://doi.org/10.3390/met10091119 - 20 Aug 2020

Cited by 12 | Viewed by 2880

Abstract

The springback in the sheet metal forming process refers to the change of shape after the load removal. It is usually undesirable, causing problems in the subsequent forming operations, in the assembly and negatively affects the quality of the final product. Numerical prediction of the springback with the use of the numerical simulation is crucial for the reduction of forming tool try-outs, reducing manufacturing costs and increasing the accuracy of the stamped part. In this work, numerical simulation was used for the springback prediction of the hat-shaped part made of advanced high-strength dual-phase steel HCT600X+Z. These numerical predictions were performed with the use of various combinations of material models to try to improve the prediction results. Furthermore, this work includes the proposed springback reduction measure. The reduction of the springback was achieved by the tool design which includes a counterpunch. The springback analysis was carried out in the side view of the formed part; the springback prediction results were compared with the experimental values. Full article

(This article belongs to the Special Issue Challenges and Achievements in Metal Forming)

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20 pages, 6925 KiB

Open AccessArticle

FEM-Based Methodology for the Design of Reduced Scale Representative Experimental Testing Allowing the Characterization of Defect Evolution during Hot Rolling of Bars

by Corentin Pondaven, Laurent Langlois, Régis Bigot and Damien Chevalier

Metals 2020, 10(8), 1035; https://doi.org/10.3390/met10081035 - 2 Aug 2020

Cited by 2 | Viewed by 2436

Abstract

Defects generated during the casting process of steel can be reduced by forming processes such as hot rolling. During these processes the effective strain, the temperature, the stress state and the alternation of the forming direction all influence the defect evolution. Analytical or numerical models are available in the literature to predict the defect evolution. However, experiments have to be carried out to identify the parameters of these models. Thus, the quality of the identification depends on the representativeness of the experiments with respect to the industrial forming process. This paper proposes a methodology to design reduced scale experiments with an improved level of representativeness. This methodology consists first in the identification of the thermomechanical parameters driving the defect evolution and the quantification of these parameters in the industrial process by FEM simulation. These last results are then utilised as criteria for the representative experiment design. In this work the methodology is applied to the rolling of bars. The representative experiment consists of successive forming operations of a cylindrical sample between shaped anvils reproducing the roll shape at a 1:10 scale. A validation is finally achieved by reproducing qualitative results concerning the evolution of voids in the vicinity of hard inclusions. Full article

(This article belongs to the Special Issue Challenges and Achievements in Metal Forming)

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22 pages, 14937 KiB

Open AccessArticle

Analysis of Tribological Properties in Disks of AA-5754 and AA-5083 Aluminium Alloys Previously Processed by Equal Channel Angular Pressing and Isothermally Forged

by Carmelo J. Luis Pérez, Rodrigo Luri Irigoyen, Ignacio Puertas Arbizu, Daniel Salcedo Pérez, Javier León Iriarte and Juan P. Fuertes Bonel

Metals 2020, 10(7), 938; https://doi.org/10.3390/met10070938 - 11 Jul 2020

Cited by 4 | Viewed by 2662

Abstract

In the present study, the wear behaviour of two aluminium alloys (AA-5754 and AA-5083) is analysed where these have been previously processed by severe plastic deformation (SPD) with equal channel angular pressing (ECAP). In order to achieve the objectives of this study, several disks made of these alloys are manufactured by isothermal forging from different initial states. The microstructures of the initial materials analysed in this study have different accumulated deformation levels. In order to compare the properties of the nanostructured materials with those which have not been ECAP-processed, several disks with a height of 6 mm and a diameter of 35 mm are manufactured from both aluminium alloys (that is, AA-5754 and AA-5083) isothermally forged at temperatures of 150 and 200 °C, respectively. These thus-manufactured disks are tested under a load of 0.6 kN, which is equivalent to a stress mean value of 18 MPa, and at a rotational speed of 200 rpm. In order to determine the wear values, the disks are weighed at the beginning, at 10,000 revolutions, at 50,000 revolutions and at 100,000 revolutions, and then the volume-loss values are calculated. This study was carried out using specific equipment, which may be considered to have a block-on-ring configuration, developed for testing in-service wear behaviour of mechanical components. From this, the wear coefficients for the two materials at different initial states are obtained. In addition, a comparison is made between the behaviour of the previously ECAP-processed aluminium alloys and those that are non-ECAP-processed. A methodology is proposed to determine wear coefficients for the aluminium alloys under consideration, which may be used to predict the wear behaviour. It is demonstrated that AA-5754 and AA-5083 aluminium alloys improve wear behaviour after the ECAP process compared to that obtained in non-ECAP-processed materials. Full article

(This article belongs to the Special Issue Challenges and Achievements in Metal Forming)

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11 pages, 9040 KiB

Open AccessFeature PaperArticle

High Temperature Cyclic Plastic Response of New-Generation ODS Alloy

by Alice Chlupová, Ivo Šulák and Jiří Svoboda

Metals 2020, 10(6), 804; https://doi.org/10.3390/met10060804 - 17 Jun 2020

Cited by 6 | Viewed by 2346

Abstract

The very recently developed coarse-grained new-generation oxide dispersion strengthened (ODS) alloys containing 5 vol.% homogeneously distributed yttrium nano-precipitates seems to be a promising oxidation-resistant structural material for applications at temperatures above 1000 °C. The primary aim of the present paper is the introduction of the new-generation oxide dispersion strengthened (ODS) alloy and the first testing of its high temperature fatigue properties at 800 °C, concurrently demonstrating a novel and very efficient methodology by using an incremental fatigue step test. The successful application of the methodology motivates the authors to test the fatigue properties of new generation ODS alloys at 1000–1200 °C in the near future. Full article

(This article belongs to the Special Issue Challenges and Achievements in Metal Forming)

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17 pages, 4158 KiB

Open AccessArticle

Calibration of Advanced Yield Criteria Using Uniaxial and Heterogeneous Tensile Test Data

by Andraž Maček, Bojan Starman, Nikolaj Mole and Miroslav Halilovič

Metals 2020, 10(4), 542; https://doi.org/10.3390/met10040542 - 22 Apr 2020

Cited by 20 | Viewed by 3711

Abstract

Conventionally, plastic anisotropy is calibrated by using standard uniaxial tensile and biaxial test results. Alternatively, heterogeneous strain field specimens in combination with full-field measurements can be used for this purpose. As reported by the literature, such an approach reduces the number of required tests enormously, but it is challenging to obtain reliable results. This paper presents an alternative methodology, which represents a compromise between the conventional and heterogeneous strain field calibration technique. The idea of the method is to use simple tests, which can be conducted on the uniaxial testing machine, and to avoid the use of advanced measuring equipment. The procedure is accomplished by conducting standard tensile tests, which are simple and reliable, and by a novel heterogeneous strain field tensile test, to calibrate the biaxial stress state. Moreover, only two of the parameters required for full characterisation need to be inversely identified from the test response; the other parameters are directly determined from the uniaxial tensile test results. This way, a dimension of optimization space is reduced substantially, which increases the robustness and effectiveness of the optimization algorithm. Full article

(This article belongs to the Special Issue Challenges and Achievements in Metal Forming)

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46 pages, 6639 KiB

Open AccessEditor’s ChoiceReview

Recent Developments and Future Challenges in Incremental Sheet Forming of Aluminium and Aluminium Alloy Sheets

by Tomasz Trzepieciński, Sherwan Mohammed Najm, Valentin Oleksik, Delia Vasilca, Imre Paniti and Marcin Szpunar

Metals 2022, 12(1), 124; https://doi.org/10.3390/met12010124 - 9 Jan 2022

Cited by 29 | Viewed by 7293

Abstract

Due to a favourable strength-to-density ratio, aluminium and its alloys are increasingly used in the automotive, aviation and space industries for the fabrication of skins and other structural elements. This article explores the opportunities for and limitations of using Single- and Two Point Incremental Sheet Forming techniques to form sheets from aluminium and its alloys. Incremental Sheet Forming (ISF) methods are designed to increase the efficiency of processing in low- and medium-batch production because (i) it does not require the production of a matrix and (ii) the forming time is much higher than in conventional methods of sheet metal forming. The tool in the form of a rotating mandrel gradually sinks into the sheet, thus leading to an increase in the degree of deformation of the material. This article provides an overview of the published results of research on the influence of the parameters of the ISF process (feed rate, tool rotational speed, step size), tool path strategy, friction conditions and process temperature on the formability and surface quality of the workpieces. This study summarises the latest development trends in experimental research on, and computer simulation using, the finite element method of ISF processes conducted in cold forming conditions and at elevated temperature. Possible directions for further research are also identified. Full article

(This article belongs to the Special Issue Challenges and Achievements in Metal Forming)

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24 pages, 4301 KiB

Open AccessReview

Asymmetrical Rolling of Aluminum Alloys and Steels: A Review

by Gabriela Vincze, Fábio J.P. Simões and Marilena C. Butuc

Metals 2020, 10(9), 1126; https://doi.org/10.3390/met10091126 - 21 Aug 2020

Cited by 33 | Viewed by 5929

Abstract

Asymmetric rolling is an attractive metal forming process due to its simplicity, low cost and capability to produce unique characteristics in materials. The asymmetry promoted by the process leads to a formation of a large collection of texture components and a refined structure which is capable to improve the mechanical behavior of metallic materials. The aim of this work is to present a perspective of the process and to construct the bases for future development and application of this technique. Thus, several aspects are addressed such as process methods (i.e., dissimilarity of the rolls diameters, rolls angular speed or friction conditions), the process parameters (i.e., total thickness reduction, thickness reduction per pass, peripheral speed ratio, rolling routes) and their effect on material properties, including texture and microstructure evolution, and mechanical properties. This review is focused on the experimental description of asymmetric rolling applied to aluminum alloys and steels. Although the asymmetric rolling application was mostly at a laboratory scale, there is a good perspective for its implementation in the industry. The pros and cons based on the up to date literature and authors’ experience are presented and discussed. Full article

(This article belongs to the Special Issue Challenges and Achievements in Metal Forming)

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