Rodas ferroviárias: análise, microestrutura e propostas de melhoria.

Chaves, Ana Paula Gonçalves

doi:10.11606/d.3.2017.tde-02032017-144335

Cited by 3 publications

(5 citation statements)

References 9 publications

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“…It is known that higher cooling rates result in smaller interlamellar spacing [20]. The same effect was verified for rail [21] and wheel [13] steels. On the pin area to be tested (wheel surface), a bainitic microstructure was found, as shown on Fig.…”

Section: Microstructuresupporting

confidence: 63%

“…Cooling can be "online", while the steel is still austenitic immediately after hot rolling, or via "offline" processes by reheating laminated rails [11]. After wheel forging or casting steps, the wheel standard specifies that these must be heat treated by means of accelerated cooling with water spray cooling (normalization) on the wheel's rolling surface, and then receives a second heat treatment (tempering) for stress relief [12,13]. This heat treatment provides reduction in interlamellar spacing of the pearlite and increase in surface hardness.…”

Section: Methodsmentioning

confidence: 99%

“…The same wheel can have hardness values with variation above 50 Brinell points and still be accepted for use. However this may cause surface defects and/or early wear [13].…”

Section: Methodsmentioning

confidence: 99%

See 2 more Smart Citations

Sliding Wear of Rail and Wheel Steels: Effect of Hardness Ratio, Normal Load and Lubrication

Viana¹,

Tressia²,

Sinatora³

2020

Tribol. Ind.

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The pin-on-disc test model system was used to simulate contact wear between wheel flange and rail gauge corner. Pins were extracted from a class C cast steel wheel and discs were extracted from premium and intermediate steel grades rail, both hypereutectoid and with hardness between 321 and 392 HB. Rails are pearlitic and the bainitic wheel is in its first life. Dry and lubricated tests were performed with normal load variation (40, 80 and 120 N). Under dry condition, there was no influence of the pair hardness to mass loss of the tribosystem studied, contrary to what is stated by literature. For the lubricated tests, mass loss was significantly lower and regardless of both, hardness ratio and normal load, than in the other tests. This shows the technological importance of: (i) implementing wheel flange lubrication (locomotive embedded process); (ii) improving rail lubrication techniques (mobile or way side process) and/or friction coefficient measurement techniques and (iii) need for revision of wheel standards and/or specifications.

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Section: Microstructuresupporting

confidence: 63%

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Sliding Wear of Rail and Wheel Steels: Effect of Hardness Ratio, Normal Load and Lubrication

Viana¹,

Tressia²,

Sinatora³

2020

Tribol. Ind.

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“…Again, it is clear that the region at the beginning of the raceway caused more wear on the tools, even with insert 2 showing more accentuated wear. According to Chaves [3] by comparing the hardness profile of the raceway with the friezes, it is possible to observe that in the raceway a greater hardening occurred when compared to the flange.…”

Section: Wear Evaluationmentioning

confidence: 99%

Tool wear analysis in milling of locomotives wheels

Pacheco¹,

Júnior²,

Mendes³

et al. 2021

SN Appl. Sci.

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The present work aims to evaluate the tool wear during the milling process of locomotives wheels—class C. A digital microscope is used to identify both the wear and the damage. The wear or damage, when propagated, can compromise the wheel roughness, which has a significant economic importance to railroad maintenance. A system for image capture composed of an ISM-PM200S INSIZE Digital Microscope and the ISM-Pro software is used to measure the flank wear. Firstly, milling process is applied with different numbers of passes. The results showed that, after flank wear, the most common wear is the thermal crack. It is also possible to observe the appearance of chipping and fracture as a consequence of the combination of thermal and mechanical cracks in the same insert. The inserts are more damaged in the raceway, due to the hardening of this region during its use. Inserts in the frieze region also showed higher values of wear, justified by the conditions of the railway. The highest values observed are around 0.1 mm. It is possible to notice that some inserts showed other damages, such as breaks and chipping, even before reaching the end of life due to wear.

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“…Chaves 62 realizou experimentos utilizando dilatometria para produzir diferentes espaçamentos interlamelares no aço SAE 1080. Os resultados dos ensaios de desgaste (pino contra disco) mostraram que os pinos com menores espaçamentos interlamelares produziram menores perdas de massa.…”

Section: V= K X P X L H (6)unclassified

Soldagem de topo com centelhamento de trilhos ferroviários: caracterização microestrutural, propriedades mecânicas e desgaste.

Bauri¹

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In general, heavy haul railways in Brazil have been subjected to operating conditions that demand better performance of the materials, as the speed of operation and the loads increase to comply with the increasing demand for transportation. For joining the rails, the Flash Butt Welding (FBW) process stands out, due to the better quality obtained on the welded joints. However, the properties of the steels may be compromised, because to the undue parameterization of the process introducing weld joint defects and heterogeneities, particularly in the Heat-Affected Zone (HAZ).Experimental reports using dilatometry to simulate the HAZ region and its properties have been published recently, however, there is a lack of detailed studies of the effects of welding parameters in the microstructure of rails. In this work, an experimental matrix was proposed, which aimed to study four parameters of the FBW process (pulse current, number of pulses, upsetting force and carbon equivalent) in both Premium and Super Premium rail steels. The matrix generated eight welding conditions. The results made it possible to understand the relationship between the microstructure and the microhardness maps on the longitudinal section of the welded joint. Tensile tests showed that the welding condition that corresponds the highest heat input presented the lowest yield strength and ultimate tensile strength. Fracture analysis of Premium rails showed ductile fracture, with double-necking in the partial austenitization region, while Super Premium rails showed brittle fracture, except for the more extreme welding condition. Sliding wear tests showed that the partial austenitization region presented more larger loss of mass in relation to the other regions, being the region most affected.In summary, the welding conditions with the lowest heat input showed the best behavior for railroad applications.

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Rodas ferroviárias: análise, microestrutura e propostas de melhoria.

Cited by 3 publications

References 9 publications

Sliding Wear of Rail and Wheel Steels: Effect of Hardness Ratio, Normal Load and Lubrication

Sliding Wear of Rail and Wheel Steels: Effect of Hardness Ratio, Normal Load and Lubrication

Tool wear analysis in milling of locomotives wheels

Soldagem de topo com centelhamento de trilhos ferroviários: caracterização microestrutural, propriedades mecânicas e desgaste.

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