High Temperature Friction and Wear Testing for Closed-Die Steel and Aluminium Forgings

Abstract:

There are several testing methodologies to characterize the friction and wear behavior of coated or special heat treated dies and forging materials for closed-die forgings. In order to measure the friction coefficient, the wear rate, galling or fretting behavior or the effect of lubricants, three different testing types (ring compression testing, a self-made high temperature rotation tribometer and hot torsion friction) are described in detail. To meet the practical requirements, the influencing factors like temperature level, sliding speed, contact pressure and specific surface treatments or coatings have to be varied in proper ranges. The results may contribute to find better friction models for finite element analysis, and consequently to a better prediction of the material flow and other related parameters. By confocal microscopy and a full metallographic investigation, the microstructural changes near the interface are studied, which lead to a better understanding of the wear and degradation mechanisms involved. These findings may help to find out countermeasures for life time improvements of the forging dies.

• Periodical: Key Engineering Materials (Volume 767)
• Pages: 204-211
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.767.204
• Online since: April 2018
• Authors: Bruno Buchmayr*, Jürgen Elser
• Keywords: Finite Element Simulation, Forging, High Temperature Friction Testing, Hot Torsion Friction Testing, Ring Compression Testing, Testing Methods, Tool Materials, Wear, Wear Analysis of Forging Dies

References

[1] T. Altan, G. Ngaile, G. Shen, Cold and hot forging: Fundamentals and Applications, ASM International, Ohio, (2005).

DOI: 10.31399/asm.tb.chffa.9781627083003

[2] J. Schey, Tribology in Metalworking: lubrication, friction and wear, American Society for Metals, ASM, (1983).

[3] T. Altan, S. Oh, H. Gegel, Metal forming fundamentals and applications, ASM, (1983).

[4] A.T. Male, M.G. Cockcroft, A method for determination of the coefficient of friction of metals under conditions of bulk plastic deformation, J. Inst. of Metals 93, (1965), 38-46.

[5] B. Buchner, Investigation of friction in closed-die warm forging of Aluminium alloys, PhD-Thesis, Montanuniversitaet Leoben, Austria, (2008).

[6] I. Finnie, C. Shaw, The friction process in metal cutting, Trans. American Soc. of Mechanical Eng. 78, (1956), 1649-1657.

[7] T. Wanheim, Friction at high normal pressures, Wear 25, (1973), 225-244.

DOI: 10.1016/0043-1648(73)90074-4

[8] N. Bay, T. Wanheim, Real area of contact and friction stress at high pressure sliding contact, Wear 38, (1976), 201-209.

DOI: 10.1016/0043-1648(76)90069-7

[9] N. Bay, Friction stress and normal stress in bulk metal-forming processes, J. of Mechan. Working Technology 14, (1987), 203-223.

DOI: 10.1016/0378-3804(87)90061-1

[10] J. Betten, Bemerkungen zum Versuch von Hohenemser, Z. für Angewandte Mathematik und Mechanik (ZAMM) 55, (1975), 149-158.

DOI: 10.1002/zamm.19750550304

[11] C.C. Chen, S. Kobayashi, Rigid-plastic finite element analysis for ring compression, Appl. Num. Methods, Proc. ASME, AMD 28, (1978), 163.

[12] T.Neumaier, Zur Optimierung der Verfahrensauswahl von Kalt-, Halbwarm- und Warmmassivumformverfahren, PhD-Thesis, University of Hannover, (2003).

[13] M. Alasti, Modellierung von Reibung und Wärmeübergang in der FEM-Simulation von Warmmassivumformprozessen, PhD-Thesis, Uni Hannover, (2008).

[14] B.-A. Behrens, A. Bouguecha, J. Mielke, G. Hirt, M. Bambach, M. Al Baouni, A. Demant, Verbesserte numerische Prozesssimulation mittels eines innovativen Reibgesetzes für die Warmmassivumformung, Schmiede-Journal (2010), March, p.5.

[15] B.-A. Behrens, A. Bouguecha, I. Lüken, J. Mielke, M. Bistron, Tribology in hot forging, in Comprehensive Materials Processing, Vol.5, Elsevier, (2014) 211-234.

DOI: 10.1016/b978-0-08-096532-1.00538-0

[16] B. Buchner, G. Maderthoner, B. Buchmayr, Characterisation of different lubricants concering the friction coefficient in forging of AA2618, J. Mat. Processing Technology 198 (2008) 41-47.

DOI: 10.1016/j.jmatprotec.2007.06.057

[17] B. Buchner, M. Buchner, B. Buchmayr, Determination of the real contact area for numerical simulation, Tribology International 42 (2009) 897-901.

DOI: 10.1016/j.triboint.2008.12.009

[18] I. Milosevic, Charakterisierung unterschiedlicher Schmiermittel zum Schmieden von Aluminiumlegierungen mittels Ringstauchversuch, Master Thesis, Montanuniversitaet Leoben, Austria, (2014).

[19] T. Yilkiran, B.-A. Behrens, B. Buchmayr: Maßnahmen zur Reparatur und Lebensdauererhöhung von Schmiedewerkzeugen, SchmiedeJournal März 2012, pp.52-57.

[20] B. Buchmayr, Damage, lifetime and repair of forging dies, Berg- u. Hüttenmänn. Monatshefte 162, (2017), 88-93.

DOI: 10.1007/s00501-016-0566-3