Tribologia - Finnish Journal of Tribology

Foreword No 3-4 (2024)

2024-12-31T06:36:13+02:00

Dear Readers,

We are happy to announce the publishing our recent issue of Tribologia. In addition to the research papers in the field of Tribology, the current issue also contains extended abstracts that have been presented during the last Nordtrib conference (Nordic Tribology Symposium 2024). In the next year, we are continuing to present the abstracts from the last Nordtrib conference. As you may be aware, the next Nordtrib conference will take place in Tampere, Finland during June 2026. The conference will be organized by Tampere University jointly with the Finnish Society for Tribology. It will be arranged in the Tampere University city center campus.

As we are again at the turning point to leave the year 2024 behind and to salute the new year 2025, we are facing again very good opportunities to improve the world with more sophisticated tribological solutions. Energy efficiency and the material performance are one of the key elements in the current tribological research areas. Tribology as science is highly multidisciplinary, involving interactions across various scientific and engineering disciplines. This broad scope enables us to bring solutions to a wide spectrum of applications. Be open-minded as tribological solutions are only limited by our imagination.

Happy Holidays and Prosperous New Year 2025!

Vuokko Marjamaa
Editor-in-Chief

History of tribology: Assessing the prehistoric impacts, progress on industrial and scientific revolution eras, and contemporary interdisciplinary research trends

2023-11-03T17:51:23+02:00

The present review focuses on the progress of tribology from the prehistoric period to the contemporary interdisciplinary research trends. During the Paleolithic period, humans used sliding friction, generated inadvertently, to make fire. The Paleolithic inhabitants possessed the knowledge to wear the chloritolite blank to fabricate a bracelet using sophisticated material removal processes. Furthermore, they wore the tooth by making holes, filled them with fillings, intended as a pathologically motivated intervention. Humans wore the tooth by in vivo drilling in the Neolithic period, used as a remedial or soothing dental procedure. The Egyptians poured water on sand to ease the movement of the statue mounted on a sled, and recently, compared to the sled dragging on dry sand, the capillary water bridges easing the sled dragging on wet sand is experimentally observed. Bearings are proposed in the renaissance era, and Leonardo da Vinci initiated friction studies, which witnessed significant progress in the industrial revolution era. The industrial revolution ushered in the use of solid lubricants and lubricating oils and grease with additives. Studies in the scientific era discussed friction, wear, and lubrication problems and reported novel, proven solutions. The expansion of tribology research into different disciplines gave birth to novel interdisciplinary studies: the mimicking of biological structures to improve adhesion, use-wear patterns of ground stone tool surfaces, tribological behavior of artificial implants and medical devices, friction in oral processing, and lubricity of two-dimensional lamellar material. Green tribology is the recent focus and it promotes sustainable tribology research for the sustenance of the earth.

An innovative evaluation of microstructure and tribological behavior of AISI 1060 and CuZn37Pb2 under laboratory and complex working conditions

2024-10-13T18:49:59+03:00

Wear is a significant industrial issue caused by the interaction of multiple complex factors rather than solely by material properties. CuZn37Pb2 and AISI 1060 steel are particularly susceptible to wear due to extensive industrial applications. This study developed a wear test tool, machined on a horizontal lathe, for testing under dry and lubricated conditions. A tribological comparison was conducted between the lathe test and a tribometer, examining factors like surface roughness, load, sliding speed, wear track diameter, track width, contact temperature, wear loss, and wear rate relative to the friction coefficient. Experiments were performed with torques ranging from 25 to 100 N, speeds of 0.30, 0.40, and 0.50 m/s, and wear track diameters of 4, 6, 8, and 10 mm. Worn surfaces and wear tracks were analyzed using optical microscopy and SEM-EDS. The influence of temperature (50 °C to 200 °C) on friction properties was studied, showing that sample morphology and test type greatly affect tribological response. Despite a wear rate calculation error below 8.12%, results indicated differences between laboratory and real-world tribological responses. This study enhances wear understanding by examining numerous previously unstudied characteristics and shows that, although wear cannot be entirely eliminated, it can be significantly minimized. Laboratory testing provides prototypes for industrial challenges, effectively linking academic research with industry needs.

A predictive system based on experimental study of lubricant blended with composite additives

2024-10-13T18:42:31+03:00

Friction & wear are main reasons for mechanical failures of heavy loaded gearboxes. However, reformed lubricant can be used to control this. This study investigates the tribological behavior of composite Nano size particles with ZDDP as add-on in EP gearbox oil for various concentrations of composite additive - 0.005, 0.01, 0.02 wt.%. All tests have conducted under variable loads (60 N, 80 N & 100N) & sliding velocities (0.65m/s, 1.05 m/s & 1.50 m/s). The experimental reading on antiwear & antifriction parameters for gear EP oil has been tested on pin on disc instrument. The response surface approach was used to build the experiment's design (DOE), which examined the ideal friction coefficient & wear volume loss in EP 220 Lubricant. Outcomes from the experimental study have been compared for two gear EP oils to indicate influence of various parameters like nanoparticles blend %, load and sliding velocity. It is found that the blending of gear EP oil with composite additives & ZDDP diminishes the wear & COF by 11.98 % and 9.81 % individually under various load & speed working conditions.

Development of a novel aerosol-lubricated ring-on-liner test methodology

2024-10-22T09:30:43+03:00

Acoustic emissions caused by fretting induced adhesion, wear and cracking

2024-12-19T00:51:27+02:00

On the surface roughness of 316L stainless steel fabricated using L-PBF additive manufacturing

2024-11-01T08:51:57+02:00

Additive manufacturing (AM) offers numerous advantages over traditional fabrication methods such as manufacturing complex parts. However, a significant limitation lies in the restricted surface quality, hindering its widespread use. While parts produced through conventional manufacturing techniques such as milling and grinding typically have an average roughness (Ra) value of less than 1–2 μm, those manufactured using laser powder bed fusion (LPBF) AM usually fall within the range of 10 to 30 μm. Surface roughness plays a critical role in various applications, as certain uses necessitate superior surface quality to prevent premature failure due to surface-induced cracking. Subpar surface quality not only compromises the strength, wear resistance, and corrosion resistance of parts but also impacts the precision of the fabricated components. Therefore, it is imperative to optimize the fabrication process and enhance the surface quality of metal parts. Moreover, the surface quality of each layer dictates the bonding strength between adjacent layers and process stability, as a high-quality preceding surface is essential for ensuring the integrity of subsequent layers. Consequently, surface roughness significantly influences process stability and the properties of metal parts produced through LPBF. This work aims at evaluating surface roughness of as printed 316L stainless steel parts made using LPBF AM process and their effects on tensile properties of the produced samples. Microscopic analyses are done to evaluate the roughness (including Ra, Rq, and Sa parameters) at different locations to evaluate the effects of different printing parameters on their size distributions. In addition, the macro-mechanical behaviour of the as printed samples is compared with the ones with polished surface.