An Experimental Investigation on Wear of Rail in Different Curve Radius

Among the rail defects, the transverse fatigue crack, which has been the most dangerous damage, is developed near the rail running face and grows perpendicular to the rail surface. Finally, the transverse fatigue crack would result in the failure of railway rail. In this paper, the rolling tests were performed using a JD-1 wheel/rail simulation facility without any lubricant. The tester is composed of a small wheel served as rail and a larger wheel served as wheel. The fatigue behavior of rail rollers with different materials and curve radius were investigated in detail by examining wear volume and wear scar using optical microscopy (OM) and scanning electronic microscopy (SEM). The results indicate that with curve radius decreasing, the wear volume of rail roller increases rapidly and the fatigue damage becomes severe. Furthermore, the cracking propagation angle increases obviously with curve radius decreasing and fatigue wear is dominating during the wear process. There appears distinct plastic deformation on the section of rail roller under small curve radius condition. For the same curve radius, the wear volume of PD3 rail is more than that of PG4 rail and the plastic deformation is more obvious. Moreover, the cracking propagation angle of PD3 rail material is smaller than that of PG4 rail. In conclusion, PG4 rail material is not suitable for the high-speed railway.

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Wear Performance of GCr15 Friction Pairs with Effect of Initial Radial Micro-Grooves

Micro and Nanosystems ◽

10.2174/1876402911666190117154327 ◽

2019 ◽

Vol 11 (1) ◽

pp. 56-61

Author(s):

Wei Yuan ◽

Shengkai Mei ◽

Song Li ◽

Zhiwen Wang ◽

Jie Yu ◽

...

Keyword(s):

Wear Rate ◽

Abrasive Wear ◽

Electrical Discharge Machining ◽

Friction Pair ◽

Wear Volume ◽

Fatigue Wear ◽

Wear Performance ◽

Wear Process ◽

Groove Test ◽

On Line

Background: Grooves may inevitably occur on the surface of the friction pair caused by severe wear or residual stress, which will play an important role on the reliability of machine parts during operation. Objective: The effect of the micro-grooves perpendicular to sliding direction on the wear performance of the friction pairs should be studied. Method: Micro-grooves can be machined on discs of friction pairs using electrical discharge machining. On-line visual ferrograph method was used to monitor the wear process to research the wear rate changing characteristic. Profilemeter and metallurgical microscope were used to observe the wear scars. Results: Comparing to the non-groove test, i) in one-groove test, wear volume and rate were approximate the same, and the wear scar was smooth, ii) when the grooves more than 4, the test running-in stage will be obviously prolonged, particularly for the test with 8 grooves on the disc, the duration of running-in stage is 4 times than that without grooves on specimen, and the wear rate and volume increase significantly, and then decrease with fluctuation, iii) the abrasive wear can be avoid with the debris stagnating in the groove, however, fatigue wear will significantly emerge. Conclusion: Abrasive wear can be avoided and smooth running-in surfaces can be obtained with proper amount of initial radial micro-grooves.

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Effect of Graphite Content on Cu–Ni–Graphite Composite for Use as Switch Slide Baseplate Materials Sliding Against U75V Steel

Journal of Tribology ◽

10.1115/1.4044728 ◽

2019 ◽

Vol 141 (12) ◽

Cited By ~ 1

Author(s):

Yiran Wang ◽

Yimin Gao ◽

Jun Takahashi ◽

Yi Wan ◽

Yunqian Zhang ◽

...

Keyword(s):

Friction Coefficient ◽

Wear Mechanism ◽

High Speed ◽

Sliding Friction ◽

Rapid Development ◽

Wear Volume ◽

Fatigue Wear ◽

Friction Coefficients ◽

Graphite Composite ◽

Graphite Content

Abstract The rapid development of high-speed railways necessitates the development of new materials for switch slide baseplates. In this study, a Cu–Ni–graphite composite, containing 1 wt% to 6 wt% graphite and prepared by powder metallurgy, was used as a potential material. Pin-on-disk wear tests were conducted to measure the sliding friction of the Cu–Ni–graphite composite against U75 V steel. The results showed that the friction coefficients gradually decreased when the graphite content in the composite ranged from 1 wt% to 4 wt% in the composite. When the graphite content was 4 wt%, the friction coefficient reached the minimum value (0.153). When the graphite content was low (1 wt% to 4 wt%), the primary wear mechanism was microcutting. An increased graphite content facilitated the generation of lubricating films and decreased the wear damage. As the graphite content increased from 4 wt% to 6 wt%, the friction coefficients also increased. The variation in the wear volume rate had the same tendency as the friction coefficient. When the graphite content exceeded 4 wt%, the primary wear mechanism was delamination and fatigue wear. Due to the tendency to form cracks on the subsurface and the plentiful generation of the spalled pits, the graphite fragments could not completely form lubricating films but separated as wear debris. The lubricating films existing on the U75 V steel were in proportion to the graphite content in the composite. The wear weight loss of the U75 V steel exhibited a reduction with increasing graphite content.

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An Investigation to the Behavior of Fatigue Crack and Rail Selection for High-Speed

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.154-155.1131 ◽

2010 ◽

Vol 154-155 ◽

pp. 1131-1136

Author(s):

Wen Zhong ◽

Jia Jie Hu ◽

Cai Yun Wang ◽

Peng Shen ◽

Qi Yue Liu

Keyword(s):

Fatigue Crack ◽

Plastic Flow ◽

Fatigue Damage ◽

High Speed ◽

Rolling Contact Fatigue ◽

Contact Fatigue ◽

High Hardness ◽

Rolling Contact ◽

Wear Volume ◽

Surface Fatigue Crack

The rolling tests of railway rail were performed using a JD-1 wheel/rail simulation facility without any lubricant. The failure behaviour of rail rollers with different materials, was investigated in detail by examining wear volume and wear scar using optical microscopy (OM) and scanning electronic microscopy (SEM). The results indicate that rail material with a high hardness appears less plastic flow after rolling test. When the plastic flow is small, the wear resistance of material appears better. However, the crack propagation is more significant and fatigue damage is more severe. There is a mutual competitive relationship between wear and surface fatigue crack. A high wear rate can reduce rolling contact fatigue damage by removing constantly surface cracks. The analysis shows that U71Mn rail is more suitable for the high-speed railway.

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Fatigue crack micromechanisms in a Cu-Zn-Al shape memory alloy with pseudo-elastic behavior

Frattura ed Integrità Strutturale ◽

10.3221/igf-esis.34.46 ◽

2015 ◽

Author(s):

Vittorio Di Cocco ◽

Francesco Iacoviello ◽

Stefano Natali ◽

Andrea Brotzu

Keyword(s):

Plastic Deformation ◽

Fatigue Crack ◽

High Temperature ◽

Shape Memory ◽

High Speed ◽

Martensitic Phase ◽

Elastic Behavior ◽

Cooling Process ◽

Austenitic Phase ◽

Structure Transition

Shape memory property characterizes the behavior of many Ti based and Cu based alloys (SMAs). In Cu-Zn-Al SMAs, the original shape recovering is due to a bcc phase that is stable at high temperature. After an appropriate cooling process, this phase (?-phase or austenitic phase) transforms reversibly into a B2 structure (transition phase) and, after a further cooling process or a plastic deformation, it transforms into a DO3 phase (martensitic phase). In ?-Cu-Zn-Al SMAs, the martensitic transformation due to plastic deformation is not stable at room temperature: a high temperature “austenitization” process followed by a high speed cooling process allow to obtain a martensitic phase with a higher stability. In this work, a Cu-Zn-Al SMA in “as cast” conditions has been microstructurally and metallographically characterized by means of X-Ray diffraction and Light Optical Microscope (LOM) observations. Fatigue crack propagation resistance and damaging micromechanisms have been investigated corresponding to three different load ratios (R=0.10, 0.50 and 0.75).

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Study on the Performance of High-Speed Rail Damage of Four Different Materials

Advances in Materials Science and Engineering ◽

10.1155/2018/5016414 ◽

2018 ◽

Vol 2018 ◽

pp. 1-6 ◽

Cited By ~ 1

Author(s):

Jiajie Hu ◽

Wen Zhong ◽

Qiyue Liu

Keyword(s):

Plastic Deformation ◽

High Speed ◽

Simulation Method ◽

Contact Condition ◽

Wear Volume ◽

Experimental Conditions ◽

High Speed Rail ◽

Contact Conditions ◽

High Speed Railway ◽

Deformation Layer

For four types of railway rails, corresponding rolling tests have been executed by using the JD-1 wheel/rail simulation device based on the Hertz simulation method, which can ensure the reciprocal contact condition between simulation rail and wheel under experimental conditions approximate to practical contact conditions. The results indicate that, for the rail material which has a higher hardness, the wear volume was less and the plastic deformation layer was thinner after the rolling test, but the crack propagation was more significant and the fatigue damage was severer, showing that its wear resistance was better. The analysis shows that the fatigue resistance of U71Mn rail was better, and considering fatigue is the main failure type for high-speed rail, so it is more suited to the high-speed railway.

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Factors Influencing the Fatigue Behavior of Ferrous Laminates

Journal of Engineering Materials and Technology ◽

10.1115/1.3225971 ◽

1987 ◽

Vol 109 (3) ◽

pp. 244-251 ◽

Cited By ~ 13

Author(s):

J. Wittenauer ◽

O. D. Sherby

Keyword(s):

Fatigue Crack ◽

Fatigue Life ◽

Carbon Steel ◽

Fatigue Behavior ◽

Layered Material ◽

Factors Influencing ◽

Ultrahigh Carbon Steel ◽

Processing History ◽

Crack Blunting ◽

Similar Processing

Laminates based on ultrahigh carbon steel were prepared and found to exhibit enhanced fatigue life as compared to a monolithic reference material. This result was achieved through the insertion of weak interlaminar regions of copper into the layered material during preparation of the laminates. The presence of these regions allowed for the operation of a delamination mechanism in advance of the propagating fatigue crack. The result was interlaminar separation and associated crack blunting. Stress-life curves show that an increase in life by as much as a factor of four is achieved for these materials when compared to monolithic specimens of similar processing history.

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Influence of turning tool wear on the surface integrity and anti-fatigue behavior of Ti1023

Advances in Mechanical Engineering ◽

10.1177/16878140211011278 ◽

2021 ◽

Vol 13 (4) ◽

pp. 168781402110112

Author(s):

Li Xun ◽

Wang Ziming ◽

Yang Shenliang ◽

Guo Zhiyuan ◽

Zhou Yongxin ◽

...

Keyword(s):

Surface Roughness ◽

Plastic Deformation ◽

Titanium Alloy ◽

Fatigue Life ◽

Tool Wear ◽

Surface Integrity ◽

Low Cycle Fatigue ◽

Fatigue Behavior ◽

Machined Surface ◽

Deformation Layer

Titanium alloy Ti1023 is a typical difficult-to-cut material. Tool wear is easy to occur in machining Ti1023, which has a significant negative effect on surface integrity. Turning is one of the common methods to machine Ti1023 parts and machined surface integrity has a direct influence on the fatigue life of parts. To control surface integrity and improve anti-fatigue behavior of Ti1023 parts, it has an important significance to study the influence of tool wear on the surface integrity and fatigue life of Ti1023 in turning. Therefore, the effect of tool wear on the surface roughness, microhardness, residual stress, and plastic deformation layer of Ti1023 workpieces by turning and low-cycle fatigue tests were studied. Meanwhile, the influence mechanism of surface integrity on anti-fatigue behavior also was analyzed. The experimental results show that the change of surface roughness caused by worn tools has the most influence on anti-fatigue behavior when the tool wear VB is from 0.05 to 0.25 mm. On the other hand, the plastic deformation layer on the machined surface could properly improve the anti-fatigue behavior of specimens that were proved in the experiments. However, the higher surface roughness and significant surface defects on surface machined utilizing the worn tool with VB = 0.30 mm, which leads the anti-fatigue behavior of specimens to decrease sharply. Therefore, to ensure the anti-fatigue behavior of parts, the value of turning tool wear VB must be rigorously controlled under 0.30 mm during finishing machining of titanium alloy Ti1023.

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Effect of Bond-Line Thickness on Fatigue Crack Growth of Structural Acrylic Adhesive Joints

Materials ◽

10.3390/ma14071723 ◽

2021 ◽

Vol 14 (7) ◽

pp. 1723

Author(s):

Yu Sekiguchi ◽

Chiaki Sato

Keyword(s):

Fatigue Crack ◽

Fatigue Crack Growth ◽

Crack Growth ◽

Fatigue Behavior ◽

Adhesive Bond ◽

Bond Line ◽

Loading Conditions ◽

Fatigue Crack Growth Resistance ◽

Line Thickness ◽

Bond Line Thickness

With an increasing demand for adhesives, the durability of joints has become highly important. The fatigue resistance of adhesives has been investigated mainly for epoxies, but in recent years many other resins have been adopted for structural adhesives. Therefore, understanding the fatigue characteristics of these resins is also important. In this study, the cyclic fatigue behavior of a two-part acrylic-based adhesive used for structural bonding was investigated using a fracture-mechanics approach. Fatigue tests for mode I loading were conducted under displacement control using double cantilever beam specimens with varying bond-line thicknesses. When the fatigue crack growth rate per cycle, da/dN, reached 10−5 mm/cycle, the fatigue toughness reduced to 1/10 of the critical fracture energy. In addition, significant changes in the characteristics of fatigue crack growth were observed varying the bond-line thickness and loading conditions. However, the predominance of the adhesive thickness on the fatigue crack growth resistance was confirmed regardless of the initial loading conditions. The thicker the adhesive bond line, the greater the fatigue toughness.

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The Performance of Polycrystalline Diamond (PCD) Tools Machined by Abrasive Grinding and Electrical Discharge Grinding (EDG) in High-Speed Turning

Journal of Manufacturing and Materials Processing ◽

10.3390/jmmp5020034 ◽

2021 ◽

Vol 5 (2) ◽

pp. 34

Author(s):

Guangxian Li ◽

Ge Wu ◽

Wencheng Pan ◽

Rizwan Abdul Rahman Rashid ◽

Suresh Palanisamy ◽

...

Keyword(s):

Electrical Discharge ◽

High Speed ◽

Flank Wear ◽

Polycrystalline Diamond ◽

Machining Efficiency ◽

Crater Wear ◽

Wear Process ◽

High Speed Turning ◽

Tools Wear ◽

Pcd Tools

Polycrystalline diamond (PCD) tools are widely used in industry due to their outstanding physical properties. However, the ultra-high hardness of PCD significantly limits the machining efficiency of conventional abrasive grinding processes, which are utilized to manufacture PCD tools. In contrast, electrical discharge grinding (EDG) has significantly higher machining efficiency because of its unique material removal mechanism. In this study, the quality and performance of PCD tools machined by abrasive grinding and EDG were investigated. The performance of cutting tools consisted of different PCD materials was tested by high-speed turning of titanium alloy Ti6Al4V. Flank wear and crater wear were investigated by analyzing the worn profile, micro morphology, chemical decomposition, and cutting forces. The results showed that an adhesive-abrasive process dominated the processes of flank wear and crater wear. Tool material loss in the wear process was caused by the development of thermal cracks. The development of PCD tools’ wear made of small-sized diamond grains was a steady adhesion-abrasion process without any catastrophic damage. In contrast, a large-scale fracture happened in the wear process of PCD tools made of large-sized diamond grains. Adhesive wear was more severe on the PCD tools machined by EDG.

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