Tribology in metal forming at elevated temperatures

Abstract

Abstract:The tribo-characteristics of metal forming at high temperatures have not yet been well understood due to the complex nature of thermal, microstructural, interaction, and process parameters. This is a review paper on the effects of temperature, coating, and lubrication to the tribological characteristics in hot forming as well as the tribometers for different metal forming processes at elevated temperatures mainly based on the experimental work. The tribological behaviors of oxides in hot forming, such as rolling and stamping, were reviewed and presented. Some commonly used surface coatings and lubricants in hot forming were given. Many types of tribometer were selected and presented and some of them provided a great potential to characterize friction and wear at elevated temperatures. Nevertheless, more testing conditions should be further investigated by developing new tribometers. Eventually, experimental results obtained from reliable tribometers could be used in theory and model developments for different forming processes and materials at high temperatures. The review also showed the great potential in further investigations and innovation in tribology.

Wear and Friction Evaluation of Different Tool Steels for Hot Stamping

“…To ameliorate the surface deterioration in hot stamping tools, it is necessary to achieve a more in-depth understanding of wear failure mechanisms [8][9][10].…”

Effect of loading on the friction and interface microstructure of lubricated steel tribopairs

“…The extensive wear debris reintroduced into the soft phosphate matrix can perform multiple contributions in the improvement of tribological performance：Firstly, the abrasive wear caused by hard Fe 2 O 3 debris was alleviated [35,36], which can be observed by comparison of SEM micrographs of wear scar in Figure 5, 6 and 7. Secondly, the digestion of oxide debris into the phosphate matrix can enhance the integral mechanical properties of tribofilm shown in Figure 8, in which the tribofilm shows a four times higher hardness than that of pure sodium metaphosphate.…”

Recent Developments and Trends in the Friction Testing for Conventional Sheet Metal Forming and Incremental Sheet Forming

“…In the" U" shaped strip friction test, the COF is estimated from measurements of strip tensions on each side of the die. The force and moment equilibrium on an element of the strip give the following formulas that can be used in determining the COF µ, the average contact pressure p s , and the average friction stress f [22] as given in Equations (30), (31), and (32) respectively:…”

“…Both groups of tests can be divided into tests with direct or indirect measurement of the values of the COF. A review of the effects of coating, lubrication, and temperature on the tribological characteristics in hot forming and the tribometers for different metal forming processes at elevated temperatures has been presented by Dohda et al [31]. Moreover, the tribological behaviors of oxides in hot forming were discussed.…”