Einblick in das Vorspannverhalten von geschraubten Verbindungen aus nichtrostendem Stahl

Stranghöner, Natalie; Jungbluth, Dominik; Afzali, Nariman; Lorenz, Christoph

doi:10.1002/stab.201710476

Cited by 19 publications

(10 citation statements)

References 2 publications

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“…6. It could be shown that the accuracy of the instrumented bolts with implanted strain gauges for measuring the preload inside the bolts is in principle acceptable, see also [12] and [13], but it has also to be pointed out that viscoplasticity occurs already during the preloading process of the stainless steel which means that these changes in the strain were measured by the strain gauges as well. This yielded to deviating values in comparison to the real 1) all bolts were preloaded to the F p,C level 2) clamping length 3) property class…”

Section: Stress Relaxation Results Fitted To the Hart's Modelmentioning

confidence: 99%

Preload losses in stainless steel bolting assemblies

et al. 2017

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Stainless steel material is a suitable choice for modern steel constructions as it has a high resistance to corrosion combined with high material strength and ductility. Furthermore, its use leads to significant reductions in maintenance. In this frame, bolted connections made of stainless steel components become more and more important to enhance the application of stainless steel not only to small parts of steel structures but also to complex structures. Whereas non preloaded stainless steel bolted connections are already widely used, according to EN 1090-2, the application of preloaded stainless steel bolting assemblies is not allowed unless otherwise specified. If they shall be used, they shall be treated as special fasteners and a procedure test is mandatory. Also EN 1993-1-4 requires that their acceptability in a particular application has to be demonstrated from test results. These restrictions are mainly caused by two facts: firstly, the viscoplastic deformation behaviour of stainless steel which might result in not negligible preload losses in the bolting assemblies themselves and secondly, the gap of knowledge regarding suitable tightening parameters and procedures for stainless steel bolting assemblies to secure a required preload in the bolting assemblies and to avoid galling. To solve these questions, research activities have been carried out in the frame of the European RFCS-research project "Execution and reliability of slip resistant connections for steel structures using CS and SS" SIROCO. The present contribution gives an initial insight into the viscoplastic deformation behaviour of stainless steel bolting assemblies which were achieved in SIROCO which shows that preloaded bolted stainless steel connections can be treated similar to those made of carbon steel.

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Section: Stress Relaxation Results Fitted To the Hart's Modelmentioning

confidence: 99%

Preload losses in stainless steel bolting assemblies

et al. 2017

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“…To close these gaps of knowledge, the European research project "Execution and reliability of slip resistant connections for steel structures using CS and SS" (SIROCO), funded by the Research Fund for Coal and Steel (RFCS) of the European Community (RFSR-CT-2014-00024), investigated, besides others, the creep and relaxation behaviour as well as the tightening and the basic preloading behaviour of austenitic and duplex (super duplex, duplex and lean duplex) stainless steel bolting assemblies according to EN ISO 4014/4017. Some results of the investigations have already been published in (5)(6)(7)(8)(9)(10). Within this contribution a short summary of the main findings is given.…”

Section: Introductionmentioning

confidence: 93%

Guidance for Preloading of Stainless Steel Bolting Assemblies using a Bolt Tightening Qualification Procedure

2019

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In modern steel constructions the use of stainless steel becomes more important, especially in corrosive environments where stainless steel is superior to carbon steel. So far, the use of stainless steel bolting assemblies for preloading in those constructions is not permitted according to EN 1090-2 and EN 1993-1-4, unless all necessary parameters for a secure preloading are defined in a procedure test on a case by case basis. The treatment of preloaded stainless steel bolting assemblies as special fasteners is based on the lack of knowledge on the preloading and time-dependent behaviour. Stainless steel tends to creep and relaxation. Furthermore, stainless steel bolting assemblies are susceptible to galling under high contact pressures which are achieved during the preloading process. It was always assumed, that these effects make a secure and efficient preloading of these types of bolting assemblies impossible. Besides that, it was in general questioned, if the resulting surface pressures of bolting assemblies according to EN ISO 4014 and EN ISO 4017 are acceptable for steel structures. Nevertheless, the construction industry highly demands the use of these types of bolting assemblies, especially when bolted connections have to be installed in corrosive environments, which was why the initiated European RFCS research project SIROCO also considered preloaded bolted connections made of stainless steels. The present paper summarizes the investigations into preloaded bolted connections made of stainless steel carried out in the frame of SIROCO. Furthermore, a guidance is given for the necessary procedure tests in form of a Bolt Tightening Qualification Procedure (BTQP) for the determination of reliable tightening parameters, considering the tightening method, a secure tightening process and the inspection criteria.

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“…An dieser Stelle ist es wichtig, darauf hinzuweisen, dass der Einsatz von vorgespannten Schraub(en)verbindungen aus nichtrostenden Stählen zurzeit normativ nicht geregelt bzw. sogar ausgeschlossen ist . Gemäß ÖNORM EN 1090‐2 dürfen Schrauben aus nichtrostendem Stahl in planmäßig vorgespannten Verbindungen nicht eingesetzt werden, „sofern nichts anderes festgelegt wird“, wobei sie dann als besondere Verbindungsmittel zu behandeln sind.…”

Section: Einführung Und Normative Situationunclassified

Experimentelle Untersuchung von Lärmschutzwandstehern und deren Befestigung auf Kunstbauten

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Stranghöner²,

Jungbluth³

2020

Stahlbau

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Im vorliegenden Aufsatz wird in Ergänzung zum Teil 1 – Ermüdungsverhalten – das Vorspannverhalten von geschraubten Verbindungen, die bei der Befestigung von Lärmschutzwandstehern auf Kunstbauten ausgeführt werden, experimentell untersucht und bewertet. In einem indikativen Vorversuch wurden insgesamt vier Messserien durchgeführt, bei denen die Verbindung mit einem vorab definierten Anziehdrehmoment jeweils dreimal hintereinander mutterseitig angezogen und wieder gelöst wurde. Als Schmiermittel wurde die Feststoffschmierpaste Molykote 1000 angewendet. Die in den Vorversuchen verwendeten Gewindebolzen und Muttern sind aus nichtrostendem Stahl A4‐80 hergestellt und weisen den Durchmesser M20 auf. Die Vorversuche dienen zur Untersuchung des Einflusses von unterschiedlichen Typen von Scheiben auf die sich ergebende Größe der Vorspannkraft im Gewindebolzen. Da geschraubte Verbindungen aus nichtrostendem Stahl derzeit normativ nicht geregelt sind, wurden am Institut für Metall‐ und Leichtbau der Universität Duisburg‐Essen ergänzende experimentelle Untersuchungen im Sinne einer Verfahrensprüfung an einem kalibrierten Anziehprüfstand durchgeführt. Auf Grundlage dieser an Gewindebolzen M16 und M20 aus nichtrostendem austenitischem Stahl A4‐80 in Kombination mit Keilsicherungsscheiben durchgeführten Anziehversuche wurde eine Verfahrensanweisung für das mutterseitige Vorspannen abgeleitet.

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Einblick in das Vorspannverhalten von geschraubten Verbindungen aus nichtrostendem Stahl

Cited by 19 publications

References 2 publications

Preload losses in stainless steel bolting assemblies

Preload losses in stainless steel bolting assemblies

Guidance for Preloading of Stainless Steel Bolting Assemblies using a Bolt Tightening Qualification Procedure

Experimentelle Untersuchung von Lärmschutzwandstehern und deren Befestigung auf Kunstbauten

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