Advances in Mechanical Joining Technologies

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: 20 June 2024 | Viewed by 7080

Special Issue Editors

Arnold Fastening System, Rochester Hills, MI, USA
Interests: mechanical joining; aluminum casting mechanical joining; Self-Pierce Rivting (SPR); flow-drill screwing

E-Mail Website
Guest Editor
School of Mechanical Engineering, Xi'an Jiaotong University, Xi'an 710049, China
Interests: metal semi-solid forming and joining; mechanical joining; plastic forming; microstructure&mechanical behavior

Special Issue Information

Dear Colleagues,

In the last few years, joining technologies have continued to advance with the specific demands from various industries. Welding and other welding-related joining technologies have been preferentially chosen by the automotive industry due to their low cost and high reliability. Nevertheless, with the global trend of light-weighting, mechanical joining with unique and inborn advantages has rapidly occupied the market for dissimilar material joining solutions. Self-pierce riveting (SPR), clinching, and other mechanical joining technologies can solve several issues concerning welding, including intermetallic layer formation, high energy consumption, and low joining strength etc. Furthermore, more affordable and reliable mechanical joining technologies have been developed and promoted by numerous innovative joining applications. To better understand the mechanisms of mechanical joining, the appropriate control of plastic deformation is the key to determine the quality of mechanical joining joints. SPR and clinching, as the most representative mechanical joining technologies, substantially bond with rivet and die design. These two factors allow material to flow into the target area and form a strong interlock. However, the wide range of material selection caused by the various material properties eventually results in unexpected consequences. Therefore, specific investigations targeting different applications should be studied to determine how to properly use plastic deformation to obtain flawless joints for mechanical joining solutions.

Advances in Mechanical Joining Technologies as a potential Special Issue offers an excellent platform to share the latest and foremost investigations in the mechanical joining field. Studies concerning simulation investigation, dissimilar material joining solutions, brittle material mechanical joining solutions, thermal and ultrasonic vibration assist mechanical joining process, and other innovative mechanical joining processes are welcome to submit to this Special Issue.

Dr. Xuzhe Zhao
Dr. Yongfei Wang
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

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.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • self-pierce riveting
  • clinching
  • thermal-assist mechanical joining
  • flow-drill screwing
  • innovative joining processes
  • joining process modeling

Published Papers (5 papers)

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Research

14 pages, 6492 KiB  
Article
Influence of High-Pressure Die Casting Process Parameters on the Compound Strength of Hybrid Components with Undercut Sheet Metal
by Lukas Bruckmeier, Aron Ringel, Uwe Vroomen, David Bailly and Andreas Bührig-Polaczek
Metals 2023, 13(10), 1717; https://doi.org/10.3390/met13101717 - 9 Oct 2023
Cited by 1 | Viewed by 1052
Abstract
Reducing the weight of parts through lightweight designs impacts CO2 emissions, especially in the automotive and transportation sectors, which have significant fuel and electric energy consumption. Using multi-material design approaches, specific material properties can be combined to achieve effective lightweighting. Commonly used [...] Read more.
Reducing the weight of parts through lightweight designs impacts CO2 emissions, especially in the automotive and transportation sectors, which have significant fuel and electric energy consumption. Using multi-material design approaches, specific material properties can be combined to achieve effective lightweighting. Commonly used metals include aluminum, which is known for its high specific strength, and steel, which is valued for its strength and structural integrity. However, joining aluminum and steel presents challenges given their different thermophysical properties and the potential formation of brittle intermetallic phases, making common joining techniques like fusion welding unsuitable. In this study, a hybrid casting process for the production of a complex workpiece from dissimilar materials was investigated. Aluminum was die-cast around a steel sheet insert. Surface structures with undercuts on the steel sheet were applied through modified cold rolling, allowing molten aluminum to flow into the channels and interlock during solidification. It was found that elevated temperatures of the melt and tool were beneficial for the interlocking, resulting in a 30% increase in compound strength. Furthermore, a reduction in both the piston position at the changeover point, between the pre-filling and cavity filling, and the melt velocity at the gate reduced the compound’s strength by 41% and 30%. Up- and downstream processes did not show any significant influence on the conducted experiments. Based on this, two main detrimental effects were observed: pre-solidification of the aluminum melt and gas entrapment. Full article
(This article belongs to the Special Issue Advances in Mechanical Joining Technologies)
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21 pages, 10067 KiB  
Article
Ductile Fracture Prediction in Hole Hemming of Aluminum and Magnesium Sheets
by Mohammad Mehdi Kasaei, José A. C. Pereira, Ricardo J. C. Carbas, Eduardo A. S. Marques and Lucas F. M. da Silva
Metals 2023, 13(9), 1559; https://doi.org/10.3390/met13091559 - 6 Sep 2023
Cited by 1 | Viewed by 795
Abstract
The present work proposes a suitable approach for predicting ductile fracture in a new joining process by plastic deformation called hole hemming. This process creates a combined form- and force-fit joint and enables the joining of lightweight materials with varying formability without requiring [...] Read more.
The present work proposes a suitable approach for predicting ductile fracture in a new joining process by plastic deformation called hole hemming. This process creates a combined form- and force-fit joint and enables the joining of lightweight materials with varying formability without requiring heating or auxiliary elements. In this process, the joinability of materials is limited by the occurrence of fracture in the outer sheet, highlighting the crucial need to accurately predict its damage during the process design phase. In this study, five different fracture criteria, including the McClintock, Rice–Tracey, Normalized Cockroft–Latham, and Brozzo and Modified Mohr–Coulomb (MMC) criteria, are examined during the joining of a challenging combination of lightweight materials (aluminum AA6082-T4 and magnesium AZ31). These criteria are calibrated by a hybrid experimental–numerical method using three tests with distinct stress states. These criteria are then implemented into the finite element model of the hole hemming process, utilizing an appropriate user subroutine. The results show that the flange edge of the outer sheet is the most prone region to fracture during the joining process, and a criterion must be able to model the fracture behavior of the material from uniaxial tension to shear to accurately predict fracture in this area. Among the examined criteria, only the MMC criterion was capable of such modeling and accurately predicted the critical displacement of the punch in the hemming stage with a negligible error (about 1%). On the other hand, the prediction accuracy of the other criteria varied significantly depending on the calibration test, resulting in errors ranging from 8.6% to 75.5%. The error of 8.6% was achieved with the Normalized Cockroft–Latham criterion calibrated by a uniaxial tension test. Thus, based on the results, the MMC criterion is recommended for ductile fracture prediction in the hole hemming process, offering valuable insights to assist in process design. Full article
(This article belongs to the Special Issue Advances in Mechanical Joining Technologies)
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10 pages, 24773 KiB  
Article
Double-Sided Self-Pierce Riveting: Electro-Mechanical Analysis of Dissimilar Al-Cu Half-Lap Butt Joints
by Rafael M. Afonso and Luís M. Alves
Metals 2023, 13(8), 1472; https://doi.org/10.3390/met13081472 - 15 Aug 2023
Viewed by 1220
Abstract
Double-sided self-pierce riveting (DSSPR) can be utilized as an alternative to self-pierce riveting (SPR) to produce butt joints through half-lap joints in dissimilar materials. The mechanical joining process makes use of tubular rivets with simple geometry that are here employed to join two [...] Read more.
Double-sided self-pierce riveting (DSSPR) can be utilized as an alternative to self-pierce riveting (SPR) to produce butt joints through half-lap joints in dissimilar materials. The mechanical joining process makes use of tubular rivets with simple geometry that are here employed to join two sheets made from aluminium (Al) and copper (Cu). This research work analyses the influence of the stainless-steel rivet on both the electrical and mechanical performance of the joint. The electrical resistance variation of the joined assembly is measured at different temperatures and compared with conventional fastened joints made from the same material combination. The mechanical performance of the aluminium–copper connections is evaluated by means of shear tests and compared to the original fastened Al-Cu joint. An experimental approach is utilized to analyse the combined influence of different mechanical and electrical parameters to assess the performance of DSSPR in electrical applications. Full article
(This article belongs to the Special Issue Advances in Mechanical Joining Technologies)
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16 pages, 13880 KiB  
Article
Long-Term Behavior of Clinched Electrical Contacts
by Jan Kalich, Marcus Matzke, Wolfgang Pfeiffer, Stephan Schlegel, Ludwig Kornhuber and Uwe Füssel
Metals 2022, 12(10), 1651; https://doi.org/10.3390/met12101651 - 30 Sep 2022
Cited by 1 | Viewed by 1741
Abstract
Joining by forming operations presents powerful and complex joining techniques. Clinching is a well-known joining process for use in sheet metalworking. Currently, clinched joints are focusing on mechanically enhanced connections. Additionally, the demand for integrating electrical requirements to transmit electrical currents will be [...] Read more.
Joining by forming operations presents powerful and complex joining techniques. Clinching is a well-known joining process for use in sheet metalworking. Currently, clinched joints are focusing on mechanically enhanced connections. Additionally, the demand for integrating electrical requirements to transmit electrical currents will be increased in the future. This integration is particularly important, for instance, in the e-mobility sector. It enables connecting battery cells with electrical joints of aluminum and copper. Systematic use of the process-specific advantages of this joining method opens up the possibility to find and create electrically optimized connections. The optimization for the transmission of electrical currents will be demonstrated for clinched joints by adapting the tool geometry and the clinched joint design. Based on a comparison of the electrical joint resistance, the limit use temperature is defined for the joining materials used based on the microstructural condition and the aging condition due to artificial aging. As a result of the investigations carried out, reliable current transmission at a constant conductor temperature of up to 120 °C can be achieved for clinched copper–copper joints. In the case of pure aluminum joints and mixed joints of aluminum and copper, long-term stable current transmission can be ensured up to a conductor temperature of 100 °C. Full article
(This article belongs to the Special Issue Advances in Mechanical Joining Technologies)
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20 pages, 7586 KiB  
Article
The Influence of Heat Treatment on the Microstructure, Surface Roughness and Shear Tensile Strength of AISI 304 Clinch Joints
by André Till Zeuner, Lars Ewenz, Jan Kalich, Sebastian Schöne, Uwe Füssel and Martina Zimmermann
Metals 2022, 12(9), 1514; https://doi.org/10.3390/met12091514 - 13 Sep 2022
Cited by 7 | Viewed by 1589
Abstract
Clinching is the manufacturing process of joining two or more metal sheets under high plastic deformation by form and force closure without thermal support and auxiliary parts. Clinch connections are applicable to difficult-to-join hybrid material combinations, such as steel and aluminum. Therefore, this [...] Read more.
Clinching is the manufacturing process of joining two or more metal sheets under high plastic deformation by form and force closure without thermal support and auxiliary parts. Clinch connections are applicable to difficult-to-join hybrid material combinations, such as steel and aluminum. Therefore, this technology is interesting for the application of AISI 304 components, as this material is widely used as a highly formable sheet material. A characteristic feature of AISI 304 is its metastability, i.e., the face-centered cubic (fcc) γ-austenite can transform into a significantly stronger body-centered cubic (bcc) α’-martensite under plastic deformation. This work investigates the effect of heat treatment—a process that involves the formation of an oxidation layer on the sheet surface—on the forming process during joining and the resulting mechanical properties of clinch joints made from AISI 304. For this purpose, different joints made from non-heat treated and heat-treated sheets were examined using classical metallography and advanced SEM techniques, accompanied by further investigations, such as hardness and feritscope measurements. The shear tensile strength was determined, and the fracture behavior of the samples was investigated. Clear influences of heat-treatment-induced surface roughness on the joint geometry and strength were observed. Full article
(This article belongs to the Special Issue Advances in Mechanical Joining Technologies)
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