PSI - Issue 5

Lars Sieber et al. / Procedia Structural Integrity 5 (2017) 1011–1018 Sieber et al. / Structural Integrity Procedia 00 (2017) 000 – 000

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Fig. 7. Charpy impact test results of the different material samples and their transition temperature T 27J

4. Summery and Outlook

The preliminary results within the ongoing study confirm available literature findings which demonstrated successful welding on old mild steels in individual cases. Therefore, the predominant opinion that unkilled old mild steels with high contents of sulphur or phosphorus are unweldable (see scenario (A) in Section 2 ) can’t be supported without further differentiation. Pending work in this project includes welding and testing of a wider variety of old mild steels as well as the variation of seam shape. Additionally, tensile tests at low temperatures have to be carried out to prevent a brittle failure in the light of strength mismatch at the weld. This will create further statistical background, allowing a more reliable answer which compositions may be weldable after all. A reliable framework of conditions how to weld old mild steels could then be very helpful. It would allow the development of new efficient repair strategies for various aging structures still in service, e.g. old bridges. Kühn, B., Lukić, M., Nussbaumer, A., Günther, H. -P., Helmerich, R., Herion, S., Kolstein, M., Walbridge, S., Androic, B., Dijkstra, O., Bucak, Ö., 2008. Assessment of Existing Steel Structures: Recommendations for Estimation of Remaining Fatigue Life. JRC Scientific and Technical Reports. JRC European Commission. Lüddecke, F., 2006. Ein Beitrag zur Ertüchtigung bestehender Stahltragwerke unter besonderer Berücksichtigung des Fügeverfahrens Schweißen. Verlag für neue Wissenschaft GmbH, Bremerhaven. Möll, R., 1997. Altstahlschweißen und Nieten im Zuge der Grunderneuerung des "Eisernen Steges" in Frankfurt am Main. Stahlbau 66 (1), 1-11. Möll, R., 2000. Grundhafte Erneuerung des großen Palmenhauses im Palmengarten in Frankfurt am Main. Stahlbau 69 (10), 741-755. Sieber, L., 2016. Zur Beurteilung der Sprödbruchgefährdung gelochter Stahltragwerke aus Flussstahl. Doctoral thesis at the Institute of Steel and Timber Construction, Technische Universität Dresden. Sims, C.E., Dahle, F.B., 1938. Effect of Aluminium on t he Properties of Medium Carbon Cast Steel. Trans. American Foundrymen’s Assoc., Vol. 46, p. 65, Stroetmann, R., Flederer, H., Schmidt, H., Sieber, L., 2009. Personenaufzug Bad Schandau - Revitalisierung eines denkmalgeschützten Turmbauwerks. Stahlbau 78 (9), 662-676. References