Heat Treatment Effects on the Mechanical Properties and Microstructure of 30MnB4 Steel Bolts

Umut Kınıt; Mehmet Bozca

doi:10.3139/120.110654

Article

Heat Treatment Effects on the Mechanical Properties and Microstructure of 30MnB4 Steel Bolts

Umut Kınıt and Mehmet Bozca

Published/Copyright: November 20, 2014

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From the journal Materials Testing Volume 56 Issue 11-12

Abstract

This study targeted the effects of heat treatment on the mechanical properties of high-strength steel bolts. High-strength steel bolt samples were manufactured by sequential cutting, cold forming, heading and heat treatment. All sample bolts were M12, and the material was 30MnB4. During the heat treatment, quenching and tempering were applied to high-strength steel. Stress-strain curves were obtained for the steel bolt samples after different heat treatments. The mechanical properties of the steel bolts, such as yield strength, tensile strength, hardness and elongation, were determined for the various heat treatments. It was concluded that heat treatment is an important process that changes the microstructure of the steel bolts and their mechanical properties. By heat treatment at different temperatures it is possible to obtain high-strength steel bolts with different properties.

Kurzfassung

Das Ziel der diesem Beitrag zugrunde liegenden Studie bestand darin, die Wärmebehandlungseffekte auf die mechanischen Eigenschaften und die Mikrostruktur von hochfesten Stahlbolzen zu untersuchen. Hierzu wurden Proben der hochfesten Stahlbolzen durch sequentielles Schneiden, Kaltverformen, Kopfanstauchen und Wärmebehandlung hergestellt. Alle Probebolzen entsprachen M 12 und waren aus dem Werkstoff 30MnB4. Während der Wärmebehandlung wurde Abschrecken und Anlassen durchgeführt. Es wurden die Spannungs-Dehnungs-Kurven der Bolzenproben nach den verschiedenen Wärmebehandlungen aufgenommen. Für die verschiedenen Wärmebehandlungen wurden die jeweiligen mechanischen Eigenschaften der Stahlbolzen, wie die Dehngrenze, die Zugfestigkeit, die Härte und die Verlängerung bestimmt. Es stellte sich heraus, dass die Wärmebehandlung einen entscheidenden Prozess darstellt, der die mechanischen Eigenschaften und die Mikrostruktur der Bolzen verändert. Durch die Wärmebehandlung bei verschiedenen Temperaturen können hochfeste Stahlbolzen mit verschiedenen Eigenschaften hergestellt werden.

Keywords: Materials testing; heat treatment; mechanical properties; microstructure; bolt strength

*Correspondence Address, Associate Prof. Dr.-Ing. Mehmet Bozca, Machine Design Division, Mechanical Engineering Faculty, Yildiz Technical University, 34349 Yildiz, Istanbul, Turkey. E-mail: mbozca@yildiz.edu.tr

MSc. Ing. Umut Kınıt, born in 1982, completed his MSc at Technical University of Istanbul, Turkey. Currently, he is working as a teaching assistant at the Technical University of Yildiz, Istanbul, Turkey. His main areas of interest are machine design and CAD.

Associate Prof. Dr.-Ing. Mehmet Bozca, born in 1965, completed his PhD at the Technical University of Istanbul, Turkey. Currently, he is working as Associate Professor at the Technical University of Yildiz in Istanbul, Turkey. His main fields of interest are machine elements and machine design.

References

1 V.Kodur, S.Kand, W.Khaliq: Effect of temperature on thermal and mechanical properties of steel bolts, Journal of Materials in Civil Engineering24 (2012), pp. 765–77410.1061/(ASCE)MT.1943-5533.0000445Search in Google Scholar

2 D. A.Fadare, T. G.Fadara, O. Y.Akanbi: Effect of heat treatment on mechanical properties and microstructure of NST 37-2 steel, Journal of Minerals and Materials Characterization and Engineering10 (2011), pp. 299–30810.4236/jmmce.2011.103020Search in Google Scholar

3 M.Kubota, T.Tarui, S.Yamasaki, T.Ochi: Development of high-strength steels for bolts, Nippon Steel Technical Report91 (2005), pp. 62–66Search in Google Scholar

4 N.Zhong, X. D.Wang, L.Wang, Y. H.Rong: Enhancement of the mechanical properties of a Nb microalloyed advanced high-strength steel treated by quenching-partitioning-tempering process, Materials Science and Engineering506 (2009), pp. 111–11610.1016/j.msea.2008.11.014Search in Google Scholar

5 L.Zong-Li, C.Xiang, L.Yan-Xiang, H.Kai-Hua: High boron iron-based alloy and its modification, Journal of Iron and Steel Research International16 (2009), No. 3, pp. 37–4210.1016/S1006-706X(09)60041-8Search in Google Scholar

6 W. S.Lee, T. T.Su: Mechanical properties and microstructural features of AISI 4340 high-strength alloy steel under quenched and tempered conditions, Journal of Materials Processing Technology87 (1999), pp. 198–20610.1016/S0924-0136(98)00351-3Search in Google Scholar

7 H. C.Lee, Y. G.Jin, Y. H.Lee, I. H.Son, D. L.Lee, Y. T.Im: Process design of high-strength bolt of fully pearlitic high carbon stell, Journal of Materials Processing Technology210 (2010), pp. 1870–187510.1016/j.jmatprotec.2010.06.017Search in Google Scholar

8 DIN ISO 933: Hexagon cap screws fully threaded, Beuth, Berlin, GermanySearch in Google Scholar

9 W. D.Callister, Jr.: Material Science and Engineering – An Introduction, John Wiley & Sons, Newy York, USA (2007)Search in Google Scholar

10 EN ISO 898-1: Mechanical properties of fasteners made of carbon steel and alloy steel, Part 1: Bolts, screws, and studs with specified property classes-Coarse thread and fine thread, Beuth, Berlin, Germany (2006)Search in Google Scholar

Published Online: 2014-11-20

Published in Print: 2014-11-17

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Articles in the same Issue

https://doi.org/10.3139/120.110654

Keywords for this article

Materials testing; heat treatment; mechanical properties; microstructure; bolt strength