Lubricating Performance of Residual Zinc Phosphate Coating on Forged Specimen in Bowden-Leben Sliding Test

Abstract:

The lubricating performance of the zinc phosphate coating employed generally in cold forging is evaluated with Bowden-Leben sliding test by changing friction conditions such as the coating thickness, specimen temperature, the tool surface roughness, contact pressure and sliding speed. A specimen for the friction test is prepared from the inner surface of an extruded square cup and the residual thickness of the lubrication coating on the specimen is controlled by using the surface expansion in forward extrusion of the cup. Experimental results showed that the specimen temperature has the strongest influence on the friction coefficient. With an increase of the specimen temperature, the friction coefficient gradually decreases until 473K, and then increases sharply. With an increase of the tool surface roughness, the friction coefficient increases slightly. Friction coefficient is formulated as a function of the specimen temperature and the tool surface roughness. The anti-galling ability of the coating is affected by the residual thickness of lubrication coating, the specimen temperature and the tool surface roughness.

• Periodical: Key Engineering Materials (Volume 767)
• Pages: 124-130
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.767.124
• Online since: April 2018
• Authors: Osamu Kada*, Zhi Gang Wang
• Keywords: Anti-Galling Ability, Cold Forging, Friction Coefficient, Tribology, Zinc Phosphate Coating

References

[1] A. Monden, K. Miyanishi, S. Yamasaki and T. Ochi, Development of middle-carbon steel bars and wire rods for cold forging, Nippon Steel Technical Report, 103 (2013) 127-132.

[2] L. Dubar, J.P. Bricout, C. Wierre and P. Meignan, New surface processes for cold forging of steels, Surface and Coatings Technology, 102 (1998) 159-167.

DOI: 10.1016/s0257-8972(97)00626-9

[3] Z.G. Wang, S. Komiyama, Y. Yoshikawa, T. Suzuki and K. Osakada, Evaluation of lubricants without zinc phosphate precoat in multi-stage cold forging, CIRP Annals-Manufacturing Technology, 64 (2015) 285-288.

DOI: 10.1016/j.cirp.2015.04.130

[4] S. Komiyama, Z. Wang, R. Tokunaga and Y. Yamaoka, Effect of tool surface roughness on friction behavior of lubricant coating in cold forging, Journal of the Japan Society for Technology of Plasticity, 51-591 (2010) 342-347.

DOI: 10.9773/sosei.51.342

[5] H. Saiki, Y. Marumo, L. Ruan and G.E. Ngaile, Evaluation method of tribological conditions in net shape cold forging of products with concave-convex profiles, Journal of the Japan Society for Technology of Plasticity, 41-477 (2000) 1036-1040.

[6] H.W. Wagener, J. Wolf, Coefficient of friction in cold extrusion, Journal of Materials Processing Technology, 44 (1994) 283-291.

DOI: 10.1016/0924-0136(94)90441-3

[7] S. Isogawa, A. Kimura, Y. Tozawa, Proposal of an evaluated method on lubricant, CIRP Annals- Manufacturing Technology, 41 (1992) 263-266.

DOI: 10.1016/s0007-8506(07)61200-1

[8] A. Danno, K. Abe and F. Nonoyama, Evaluation of lubricating performance of zinc phosphate coatings by cold piercing test, Journal of the Japan Society for Technology of Plasticity, 24-265(1983) 213-220.