Achtung:

Sie haben Javascript deaktiviert!
Sie haben versucht eine Funktion zu nutzen, die nur mit Javascript möglich ist. Um sämtliche Funktionalitäten unserer Internetseite zu nutzen, aktivieren Sie bitte Javascript in Ihrem Browser.

A chance for life. Start your studies in Paderborn now: www.uni-paderborn.de/en/zv/3-3/formalities

Photo: Paderborn University

M. Sc. Benedikt Uhe

Contact
Publications
M. Sc. Benedikt Uhe

Transregional Collaborative Research Centre 285

Member - Research Associate - Teilprojekt A01

Werkstoff- und Fügetechnik

Research Associate - Simulation

Phone:
+49 5251 60-3760
Office:
P1.4.16
Visitor:
Pohlweg 47-49
33098 Paderborn

Open list in Research Information System

2022

Process-adapted temperature application within a two-stage rivet forming process for high nitrogen steel

C. Kuball, B. Uhe, G. Meschut, M. Merklein, Proceedings of the Institution of Mechanical Engineers Part L-Journal of Materials-Design and Applications (2022), pp. 1-17

DOI


2021

Influence of the Rivet Coating on the Friction during Self-Piercing Riveting

B. Uhe, C. Kuball, M. Merklein, G. Meschut, Key Engineering Materials (2021), 883, pp. 11-18

The number of multi-material joints is increasing as a result of lightweight design. Self-piercing riveting (SPR) is an important mechanical joining technique for multi-material structures. Rivets for SPR are coated to prevent corrosion, but this coating also influences the friction that prevails during the joining process. The aim of the present investigation is to evaluate this influence. The investigation focuses on the common rivet coatings Almac® and zinc-nickel with topcoat as well as on uncoated rivet surfaces. First of all, the coating thickness and the uniformity of the coating distribution are analysed. Friction tests facilitate the classification of the surface properties. The influence of the friction on the characteristic joint parameters and the force-stroke curves is analysed by means of experimental joining tests. More in-depth knowledge of the effects that occur is achieved through the use of numerical simulation. Overall, it is shown that the surface condition of the rivet has an impact on the friction during the joining process and on the resulting joint. However, the detected deviations between different surface conditions do not restrict the operational capability of SPR and the properties of uncoated rivet surfaces, in particular, are similar to those of Almac®-coated rivets. It can thus be assumed that SPR with respect to the joining process is also possible without rivet coating in principle.


Strength of self-piercing riveted Joints with conventional Rivets and Rivets made of High Nitrogen Steel

B. Uhe, C. Kuball, M. Merklein, G. Meschut, 2021

The use of high-strength steel and aluminium is rising due to the intensified efforts being made in lightweight design, and self-piercing riveting is becoming increasingly important. Conventional rivets for self-piercing riveting differ in their geometry, the material used, the condition of the material and the coating. To shorten the manufacturing process, the use of stainless steel with high strain hardening as the rivet material represents a promising approach. This allows the coating of the rivets to be omitted due to the corrosion resistance of the material and, since the strength of the stainless steel is achieved by cold forming, heat treatment is no longer required. In addition, it is possible to adjust the local strength within the rivet. Because of that, the authors have elaborated a concept for using high nitrogen steel 1.3815 as the rivet material. The present investigation focusses on the joint strength in order to evaluate the capability of rivets in high nitrogen steel by comparison to conventional rivets made of treatable steel. Due to certain challenges in the forming process of the high nitrogen steel rivets, deviations result from the targeted rivet geometry. Mainly these deviations cause a lower joint strength with these rivets, which is, however, adequate. All in all, the capability of the new rivet is proven by the results of this investigation.


Self-Piercing Riveting Using Rivets Made of Stainless Steel with High Strain Hardening

B. Uhe, C. Kuball, M. Merklein, G. Meschut, in: Forming the Future - Proceedings of the 13th International Conference on the Technology of Plasticity. The Minerals, Metals & Materials Series., Springer, 2021, pp. 1495-1506

Self-piercing riveting is an established technique for joining multi-material structures in car body manufacturing. Rivets for self-piercing riveting differ in their geometry, the material used, the condition of the material and their surface condition. To shorten the manufacturing process by omitting the heat treatment and the coating process, the authors have elaborated a concept for the use of stainless steel with high strain hardening as a rivet material. The focus of the present investigation is on the evaluation of the influences of the rivet’s geometry and material on its deformation behaviour. Conventional rivets of types P and HD2, a rivet with an improved geometry made of treatable steel 38B2, and rivets made of the stainless steels 1.3815 and 1.4541 are examined. The analysis is conducted by means of multi-step joining tests for two material combinations comprising high-strength steel HCT70X and aluminium EN AW-5083. The joints are cut to provide a cross-section and the deformation behaviour of the different rivets is analysed on the basis of the measured changes in geometry and hardness. In parallel, an examination of the force-stroke curves provides further insights. It can be demonstrated that, besides the geometry, the material strength, in particular, has a significant influence on the deformation behaviour of the rivet. The strength of steel 1.4541 is seen to be too low for the joining task, while the strength of steel 1.3815 is sufficient, and hence the investigation confirms the capability of rivets made of 1.3815 for joining even challenging material combinations.


Selective application of different forming temperatures for individual process stages in a rivet manufacturing process with high nitrogen steel

C. Kuball, B. Uhe, G. Meschut, M. Merklein. Selective application of different forming temperatures for individual process stages in a rivet manufacturing process with high nitrogen steel. In: 2nd International Conference on Advanced Joining Processes, Sintra, PT, 2021.


2020

Improvement of a rivet geometry for the self-piercing riveting of high-strength steel and multi-material joints

B. Uhe, C. Kuball, M. Merklein, G. Meschut, Production Engineering (2020), 14, pp. 417-423

As a result of lightweight design, increased use is being made of high-strength steel and aluminium in car bodies. Self-piercing riveting is an established technique for joining these materials. The dissimilar properties of the two materials have led to a number of different rivet geometries in the past. Each rivet geometry fulfils the requirements of the materials within a limited range. In the present investigation, an improved rivet geometry is developed, which permits the reliable joining of two material combinations that could only be joined by two different rivet geometries up until now. Material combination 1 consists of high-strength steel on both sides, while material combination 2 comprises aluminium on the punch side and high-strength steel on the die side. The material flow and the stress and strain conditions prevailing during the joining process are analysed by means of numerical simulation. The rivet geometry is then improved step-by-step on the basis of this analysis. Finally, the improved rivet geometry is manufactured and the findings of the investigation are verified in experimental joining tests.




2019


Open list in Research Information System

The University for the Information Society