scholarly journals Abrasive Wear, Scuffing and Rolling Contact Fatigue of DLC-Coated 18CrNiMo7-6 Steel Lubricated by a Pure and Contaminated Gear Oil

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7086
Author(s):  
Waldemar Tuszyński ◽  
Remigiusz Michalczewski ◽  
Edyta Osuch-Słomka ◽  
Andrzej Snarski-Adamski ◽  
Marek Kalbarczyk ◽  
...  
Keyword(s):  
Abrasive Wear ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Solid Particles ◽  
Rolling Contact ◽  
Lubricating Oil ◽  
Gear Teeth ◽  
Ball Rolling ◽  
Gear Oil ◽  
Gear Oils

Due to extreme working conditions of mining conveyors, which contaminate gear oil with solid particles, their transmissions are exposed to intensive abrasion, scuffing, and even rolling contact fatigue (pitting). These effects shorten gear life. To prevent their occurrence, a wear-resistant coating can be deposited on gear teeth. The resistance to abrasive wear, scuffing, and pitting was investigated and reported in the article. Simple, model specimens were used. Abrasive wear and scuffing were tested using a pin-and-vee-block tribosystem in sliding contact. A cone–three-ball rolling tribosystem was employed to test pitting. The material of the test specimens (pins, vee blocks, cones) was 18CrNiMo7-6 case-hardened steel. Two types of DLC (Diamond-like Coatings) coatings were tested, W-DLC and W-DLC/CrN. The vee blocks and cones were coated. Two industrial gear oils were selected to lubricate the specimens: one with a mineral and one with a synthetic PAO (polyalphaolephine) base, as pure oil or contaminated with solid particles from a coal mine. The results show that, to minimize the tendency to abrasion, scuffing, and pitting of specimens made of 18CrNiMo7-6 steel, the W-DLC/CrN coating should be deposited. This coating also gives very good protection when the lubricating oil is contaminated.

Observation of Crack Initiation Direction around Inclusions in SUJ2 under Single-Ball Rolling Contact Fatigue

2013 ◽  
Vol 307 ◽  
pp. 342-346 ◽  
Author(s):  
Shintaro Hazeyama ◽  
Justyna Rozwadowska ◽  
Katsuyuki Kida ◽  
Edson Costa Santos ◽  
Takashi Honda ◽  
...  
Keyword(s):  
Crack Initiation ◽  
Empirical Data ◽  
Rolling Contact Fatigue ◽  
Testing Machine ◽  
Contact Fatigue ◽  
Rolling Contact ◽  
Ball Rolling

A newly developed single-ball RCF testing machine was used in order to investigate crack initiation direction within SUJ2. From empirical data, it was found that the distribution of crack initiation direction at N = 1.0x106 cycles is very close to that at N = 1.0x107. This means that the cracks that do not cause failure stop growing by 1.0x106 cycles. Some cracks however continue to grow towards the surface, at an angle of 135 degrees.

scholarly journals Dry Rolling/Sliding Wear of Bainitic Rail Steels under Different Contact Stresses and Slip Ratios

Materials ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 4678
Author(s):  
Jiapeng Liu ◽  
Yingqi Li ◽  
Yinhua Zhang ◽  
Yue Hu ◽  
Lubing Shi ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
Abrasive Wear ◽  
Contact Stress ◽  
Wear Mechanism ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Rolling Contact ◽  
Wear Loss ◽  
Fatigue Wear ◽  
Slip Ratio

This study aims to deeply understand the effect of contact stress and slip ratio on wear performances of bainitic rail steels. The results showed that the wear loss increased as the contact stress and slip ratio increased. Based on the surface damage morphology and microstructural analyses, it revealed that the rolling contact fatigue wear mechanism played a significant role under the low slip ratio, but the dominant wear mechanism transferred to the abrasive wear at the high slip ratio. Meanwhile, the bainitic steel specifically presented worse wear resistance under the abrasive wear mode. Compared with the influence of a slip ratio, the increase in contact stress led to severer plastic flows and contributed to the propagation of cracks. In addition, the contact stress and slip ratio had the opposite effect on the friction coefficient, that is, the friction coefficient of bainitic steels behaved the inverse proportion with the contact stress, but positive proportion with the slip ratio. At last, the increase in slip ratio had more significant effect on the reduction of retained austenite (RA) than the enlargement of contact stress due to the fact that the RA would probably be removed before the martensitic transformation occurred under the abrasive wear mechanism.

Intelligent Control System for Ceramics Ball Test Rig

2010 ◽  
Vol 37-38 ◽  
pp. 580-583
Author(s):  
Jing Ling Zhou ◽  
Jian Chun Chen ◽  
Guo Qing Wu ◽  
Xiao Yang Chen
Keyword(s):  
Signal Processing ◽  
Control System ◽  
Intelligent Control ◽  
Rolling Contact Fatigue ◽  
Spectral Characteristics ◽  
Contact Fatigue ◽  
Rolling Contact ◽  
Test Rig ◽  
Intelligent Control System ◽  
Ball Rolling

An intelligent control system for ceramics ball rolling contact fatigue test rig based on LabVIEW was designed. The system consists of four functional blocks, which are data acquisition block, signal processing block, state recognition block and diagnosis decision-making block. The data in the test process such as load, vibration, speed, fatigue life and so on, are collected and recorded automatically. This system can alarm or shutdown once the test rig state is abnormal or the truncate time is satisfied. By using wavelet transform and other methods in the vibration signal processing and analysis, the failure parts can be detected accurately according to the spectral characteristics and the fault characteristic frequency of the parts. The intelligent control system has practical advantages. The high precision, fast response, low cost, accurate judgment and convenience manipulation are very desirable for ceramics ball rolling contact fatigue experiment.

Observation of Subsurface Crack of Carburized Steel (SCM415) under Single-Ball Rolling Contact Fatigue over 107 Cycles

2019 ◽  
Vol 298 ◽  
pp. 19-23
Author(s):  
Masato Fukuda ◽  
Koshiro Mizobe ◽  
Katsuyuki Kida
Keyword(s):  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Rolling Contact ◽  
Subsurface Crack ◽  
Subsurface Cracks ◽  
Carburized Steel ◽  
Ball Rolling

Bearing fails due to the flaking failure which is caused by the subsurface cracks. The observation of the subsurface cracks is not easy beacause the cracks propagate inside the material. In order to observe the whole subsurface cracks, we performed rolling contact fatigue (RCF) tests of carburized SCM415 until over 107 cycles with the single-ball RCF machine. After the RCF tests, we directly observed the subsurface cracks.

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