著者

Vilma Ratia Kati Valtonen Anu Kemppainen Veli-Tapani Kuokkala

出版者

(社)日本トライボロジー学会

雑誌

Tribology Online (ISSN:18812198)

巻号頁・発行日

vol.11, no.2, pp.410-416, 2016-04-30 (Released:2016-04-30)

参考文献数

10

被引用文献数

7

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The role of edge wear was studied in impact-abrasion testing conditions with an impeller-tumbler type test device. Three steels with different mechanical properties were tested at 30° and 90° sample angles using natural granite stone as abrasive particles. The edge and planar (inner) areas were carefully exposed to the same conditions by using tightly fitted two-part samples to obtain relevant information about the differences in their wear behavior. The role of edge-concentrated wear was dominant in all materials, and the edge wear rate was several times higher than the wear rate of the inner parts of the specimens. The difference in wear rate was particularly large in short tests and with the 90° sample angle. However, the dominance of the edge-concentrated wear decreased as the test duration became longer. The wear mechanism was largely microfatigue in all materials, but the samples tested at the 30° sample angle showed more microcutting in comparison to the 90° samples. Moreover, the role of microcutting was higher in the wear of the edge parts than in the inner parts.

著者

Vilma Ratia Kati Valtonen Anu Kemppainen Veli-Tapani Kuokkala

出版者

(社)日本トライボロジー学会

雑誌

Tribology Online (ISSN:18812198)

巻号頁・発行日

vol.8, no.2, pp.152-161, 2012-02-15 (Released:2013-02-15)

参考文献数

13

被引用文献数

21

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Energy can be saved by enhancing the service life of machinery and by designing lighter units. These design changes enable, for example, lower fuel consumption and larger payloads. The implementation of this kind of solutions, however, requires development of better wear resistant materials. In this study, the wear resistance of a structural steel and three grades of wear resistant steel was evaluated with granite abrasive in tests simulating the conditions in heavy machinery in mining and transportation. Two high-stress abrasion and one impact-abrasion wear testing methods were used. In all tests, higher hardness led to decreased mass loss, but in impact-abrasion the hardness dependence was smaller than in the heavy abrasion tests. This may, however, at least partly result from deformation of softer materials over the sample edges, which is not shown as mass loss. Wear surfaces of structural steel samples exhibited the highest degree of plastic deformation due to their lower hardness and higher ductility compared to the wear resistant steels. On the other hand, in harder materials the scratches were more visible, indicating a change in wear mechanism. Both differences and similarities in the behavior and wear mechanisms of the selected steels were observed in the applied conditions.

著者

Alan Hase Masaki Wada Hiroshi Mishina

出版者

(社)日本トライボロジー学会

雑誌

Tribology Online (ISSN:18812198)

巻号頁・発行日

vol.3, no.5, pp.298-303, 2008-10-15 (Released:2008-10-15)

参考文献数

22

被引用文献数

6 16

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The relationship between acoustic emission (AE) signals and wear phenomena in severe-mild wear transition is discussed on the basis of the results of observations of wear particles and worn surfaces of steel. Each wear mode, severe wear or mild wear, is reproduced for a different sliding velocity. The influence of relative humidity on mild wear is examined. We found a reduction in the true area of contact and the size of wear particles decreases the AE signal level in severe-mild wear transition. In the mild wear mode, an increase in the number of transfer particles lying between the sliding surfaces decreases the AE signal level. Further, a linear relationship is observed between the AE mean value and the specific wear rate, regardless of the wear mode. This is because the AE signals generated by the formation and removal of transfer particles mainly originate under conditions of repeated dry rubbing.

著者

Uzuhiko Tsuboi

出版者

(社)日本トライボロジー学会

雑誌

Tribology Online (ISSN:18812198)

巻号頁・発行日

vol.6, no.3, pp.160-167, 2011-01-31 (Released:2011-01-31)

参考文献数

10

被引用文献数

2

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It is inspiring to discover technology related to tribology throughout the history of mankind. This paper describes sketches produced by da Vinci in the 15th century corresponding to modern bearings and notable tribological achievements in Japan from ancient times. Explained herein are a project to construct bearing models based on da Vinci’s sketches, a fire-making device used in Japan since ancient times, shura sleds that were widely used in Japan, investigations of the revolving stage mechanisms of Japan’s oldest surviving theater, and ingenious automated doll devices of Japan’s Edo period that paved the way to the creation of modern humanoid robots. Lastly, this paper touches on how these technologies led to the development of Japan’s bearing industry.

著者

Kanao Fukuda Joichi Sugimura

出版者

(社)日本トライボロジー学会

雑誌

Tribology Online (ISSN:18812198)

巻号頁・発行日

vol.8, no.1, pp.22-27, 2013-01-31 (Released:2013-01-31)

参考文献数

14

被引用文献数

1 14

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The authors have clarified that trace impurities such as water and oxygen inevitably contained in a hydrogen environment influence friction and wear of metallic materials substantially and even often govern them. In this study, an experimental technique was devised to enable sliding tests in a hydrogen environment which contains controlled concentration of water and virtually no oxygen as impurities. By comparing data of Fe sliding tests between this study and our previous studies, the influences of water and oxygen were understood separately. Water without oxygen as impurity in a hydrogen environment decreased wear of pure Fe while oxygen in additional to water increased the wear. Sliding of pure Fe consumed water when a hydrogen environment contained only water while it produced water and consumed oxygen when the environment contained both water and oxygen. The number of water molecules consumed by sliding in a hydrogen environment with water more than 5,000 ppb and without oxygen was larger than the estimated number of nascent Fe atoms by sliding. This suggests that multi-layer adsorption of water molecules decreased the wear of pure Fe.