The Effect of Heat Treatment on Formability of Ultra-Fine Grained AA6061 for Bolt Manufacturing

Abstract:

Equal channel angular extrusion (ECAE) was used before and after artificial aging to investigate the effect of heat treatment on formability of bulk nanostructure of commercially available aluminum alloy of AA6061 in the present study. In the ECAE, route A was applied up to four or eight passes by using the split dies set-up. The three-stage bolt forming using the ultra-fine grained specimens was carried out to check formability of the material. In the present experiments, the bolt forming was successful with the specimen prepared by the ECAE after artificial aging whilst it was not successful with the specimen prepared by a reverse process sequence. The strength increase was confirmed by the tension and microhardness tests and compared to the result of conventional AA2024 bolt made by the conventionally heat treated specimen. It was found that the strength was comparable to the level of the heat treated conventional one although the actual value was a little bit lower. In addition, it was demonstrated that the heat treatment sequence is important to achieve proper formability of the ultra-fine grained material to manufacture the high strength bolt.

• Periodical: Key Engineering Materials (Volume 443)
• Pages: 164-169
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.443.164
• Online since: June 2010
• Authors: Jun Seok Choi, Young Gwan Jin, Yong Taek Im
• Keywords: Aging, ECAE, Formability, High-Strength Bolts, Ultra-Fine Grained Aluminum

References

[1] V.M. Segal: Mater. Sci. Eng. A Vol. 197 (1995), p.157.

[2] R.Z. Valiev and T.G. Langdon: Prog. Mater. Sci. Vol. 51 (2006), p.881.

[3] C.S. Chung, J.K. Kim, H.K. Kim and W.J. Kim: Mater. Sci. Eng. A Vol. 337 (2002), p.39.

[4] W.F. Smith, in: Structure and properties of engineering alloys, McGraw-Hill, New York, USA (1993).

[5] S. Ferrasse, V.M. Segal, K.T. Hartwig and R.E. Gofortha: J. Mater. Res. Vol. 12 (1997), p.1253.

[6] J.K. Kim, H.G. Jeong, S.I. Hong, Y.S. Kim and W.J. Kim: Scripta Mater. Vol. 45 (2001), p.901.

[7] V.S. Zhernakov, V.V. Latysh, V.V. Stolyarov, A.I. Zharikov and R.Z. Valiev: Scripta Mater. Vol. 44 (2001), p.1771.

DOI: 10.1016/s1359-6462(01)00737-0

[8] A. Yanagida, K. Joko and A. Azushima: J. Mater. Proc. Tech. Vol. 201 (2005), p.390.

[9] J.S. Choi, Y.G. Jin, H.C. Lee and Y.T. Im, in: Proceedings of 2 nd International Conference on Ultrafine Grained and �anostructured Materials, Tehran, Iran (2009).

[10] Y.G. Jin, I.H. Son, S.H. Kang and Y.T. Im: Mater. Sci. Eng. A Vol. 503 (2009), p.152.

[11] A. M. Vernice, in: Annual book of ASTM standards, ASTM International, West Conshohocken, USA (2006).

[12] Korea Standards Association, Mechanical properties of non-ferrous metal fasteners, KS B0145, Korea (1996).