RELIABILITY ANALYSIS OF THE MECHANICAL PROPERTIES OF 30MnB4 HIGH STRENGTH STEEL BOLTS UNDER STATIC LOADING CONDITIONS

The objective of this study is to investigate the mechanical properties of high-strength steel bolts under static loading conditions based on reliability analysis. High-strength steel bolts samples were manufactured by sequential cutting, cold forming, heading and heat treating. All sample bolts were fully threaded hexagon cap M12 bolts, and the material was 30MnB4. During the heat treatment, quenching and tempering processes were applied to the high-strength steel bolts. A standard tensile test was performed on the samples. 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 and tensile strength, were determined for the different heat treatments. Reliability analyses of the mechanical properties of the steel bolts under static loading conditions were conducted. The mean values, standard deviations and standard variables of yield strength and tensile strength were calculated. It was concluded that the reliability levels of yield strength and tensile strength (R>99%) satisfied the required yield strength values RP0,2 and tensile strength values Rm given in the literature. Furthermore, having high reliability levels production is an advantage for manufacturer both in local and international markets.

Keywords:

Reliability analysis, heat treatment mechanical properties, bolt,

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[1] U. Kınıt and M. Bozca, (2014) Heat Treatment Effects on the Mechanical Properties and Microstructure of 30MnB4 Steel Bolts, Material Testing, 56, 945-949.
[2] H.K.D.H. Bhadeshia, (2015) Bainite in Steels: Theory and Practice, 3rd ed., Money Publishing.
[3] V. Kodur, S. Kand, and W. Khaliq (2012) Effect of Temperature on Thermal and Mechanical Properties of Steel Bolts, Journal of Materials in Civil Engineering, 24, 765-774.
[4] M. Kubota, T. Tarui, S. Yamasaki, T. Ochi (2005) Development of high-strength steels for Bolts, Nippon Steel Technical Report, 91, 62-66.
[5] N. Zhong, X.D. Wang, L. Wang, Y.H. Rong, (2009) Enhancement of the mechanical properties of a Nb-microalloyed advanced high-strength steel treated by quenching- partitioning -tempering process, Materials Science & Engineering, 506, 111-116.
[6] L. Zong-Li, C. Xiang, L. Yan-Xiang, H. Kai-Hua, (2009) High boron iron-based alloy and its modification”, Journal of Iron and Steel Research International 16 no.3, 37-42.
[7] R. L. Norton, Machine Design, An Integrated Approach, (2011) 4th ed., Pearson Inc.
[8] B. Bertsche, (2008) Reliability in Automotive and Mechanical Engineering, Springer.
[9] VDI 4001: Verein Deutscher Ingenieure –Handbuch Technishe Zuverlässigkeit.
[10] R.I. Stephens, A. Fatemi, R.Stephens, H.O. Fuchs, (2001) Metal Fatigue in Engineering, Canada: John Wiley & Sons.
[11]. X. Du, A. Sudjianto, B. Huang, (2005) Reliability-Based Design with the Mixture of Random and Internal Variables, Journal of Mechanical Design, 127.
[12] H. Wang, N. H. Kim, Y.J. Kim, (2006) Safety Envelope for Load Tolerances and its Application to Fatigue Reliability Design , Journal of Mechanical Design, 128.
[13] W. D. Callister, Jr. Material Science and Engineering, an Introduction, (2007) John Wiley & Sons, Inc.
[14] Hexagon cap screws fully threaded, DIN 933.
[15] Mechanical properties of fasteners made of carbon steel and alloy steel-Part1: Bolts, screws, and studs with specified property classes-Coarse thread and fine thread, EN-ISO 898-1

Sigma Mühendislik ve Fen Bilimleri Dergisi-Cover

ISSN: 1304-7191
Yayın Aralığı: Yılda 4 Sayı
Yayıncı: Yıldız Teknik Üniversitesi

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