Papers by Rafael Luciano Dalcin
Editora Ilustração eBooks, Dec 31, 2022
Journal of the Brazilian Society of Mechanical Sciences and Engineering, May 25, 2024
The international journal of advanced manufacturing technology/International journal, advanced manufacturing technology, Apr 4, 2024
The present investigation aims correlate the roughness, film thickness and friction coefficient w... more The present investigation aims correlate the roughness, film thickness and friction coefficient with pitting wear resistance along the rolling-sliding contact fatigue of forged and plasma nitrided gears. The hypothesis of this work is that the pitting wear resistance of forged gears can be greatly improved by pulsed plasma nitriding. Weibull’s statistical analysis confirms that nitrided gears with 24 vol.% N2 showed the lowest pitting wear rates among the investigated conditions, which was attributed to the best combination between surface hardness, fracture toughness, compound layer thickness, and phases on surface. The pitting wear intensifies with increasing roughness, but this same behavior was not observed between the wear evolution and the maximum shear stress field in the sub-surface. Another interesting fact is that nitrided gears with 24 vol.% N2 (best condition), have a greater film thickness at the end of the rolling-sliding contact fatigue, which gives it greater protect...
Journal of Materials Research and Technology
The new continuous cooling bainitic steels (CCBS) are an excellent alternative when high hardness... more The new continuous cooling bainitic steels (CCBS) are an excellent alternative when high hardness, toughness and fatigue resistance are required. However, it is estimated that the wear rate of the CCBS is insufficient for application in highly mechanical loaded components, being necessary to improve the surface properties. The objective of this study is to analyze the effects of plasma nitriding on the microstructure and wear properties of DIN18MnCrSiMo6-4 continuous cooling bainitic steel. Therefore, treatments lasting 6 hours were conducted with a pressure of 3 mbar, a gas mixture composed of 76% N2 + 24% H2, and a temperature of 400, 450, 500 and 550 °C, respectively. The samples were analyzed by scanning electron microscopy, X-ray diffraction, microhardness and reciprocal sliding wear tests. Under the conditions investigated, it was possible to obtain a compound layer and to achieve an increase of up to 393% in surface hardness, however, the use of higher processing temperatures...
Materials Research
For the first time, the influence of gas mixture on first damage resistance of a plasma nitrided ... more For the first time, the influence of gas mixture on first damage resistance of a plasma nitrided DIN 18MnCrSiMo6-4 bainitic steel was investigated. Samples were nitrided at 500 °C with three different N 2-H 2 gas mixtures, containing 5, 24, and 76 vol.% N 2. Samples were characterized concerning the resulting roughness, microstructure, compound layer's phase composition, residual stresses in the diffusion zone, and surface hardness. Tribological ball-on-flat tests were carried out in reciprocal mode using zirconia as ball material for friction coefficient and the compound layer resistance until the first damage. The test results were evaluated statistically by analysis of variance (ANOVA). As the amount of nitrogen in the gas mixture decreases, the ε-Fe 2-3 (C)N content in the compound layer decreases. A γ'-Fe 4 N monophasic compound layer was achieved at 5 vol.% N 2 gas mixture. The diffusion zone as expected presented compressive residual stresses with the highest values near the surface. In the tribological tests, better results were obtained for 5 and 24 vol.% N 2 in the gas mixture as higher amounts of γ'-Fe 4 N were formed. The 76 vol.% N 2 gas mixture led to a brittle behavior, due to the biphasic compound layer (γ'-Fe 4 N and ε-Fe 2-3 (C)N) with a predominant content of ε-Fe 2-3 (C)N.
American Journal of Materials Science, 2018
In this study, coatings WC-10Co-4Cr and Cr3C2-25NiCr were deposited on the AISI H13 steel by oxy-... more In this study, coatings WC-10Co-4Cr and Cr3C2-25NiCr were deposited on the AISI H13 steel by oxy-fuel Thermal spraying (HVOF). This coating increases the wear resistance of surfaces subjected to severe conditions, such as: abrasive wear, thermal fatigue and plastic deformation. The coatings microstructure, hardness and wear resistance are investigated through friction and wear tests performed through a pin-on-disc type tribometer following the procedures defined in ASTM G99-04. It was verified that both materials used in the spraying have high resistance to wear, however, in the sample coated with Cr3C2-25NiCr there was a greater removal of material during the test.
pela orientação, confiança depositada e pelo aprendizado transmitido. À SSAB e especialmente aos ... more pela orientação, confiança depositada e pelo aprendizado transmitido. À SSAB e especialmente aos Engenheiros: João Ricardo Boff Preichard e Lisandro Peliciolli, pelo conhecimento transmitido e por terem fornecido o aço DOMEX 700 MC.
In this study, the sliding wear of a DIN 18MnCrSiMo6-4 continuous cooling bainitic steel plasma n... more In this study, the sliding wear of a DIN 18MnCrSiMo6-4 continuous cooling bainitic steel plasma nitrided with a nitrogen rich gas composition was investigated. To evaluate the influence of processing time and temperature on mechanical and microstructural characteristics of nitrided layer, the samples were nitrided at 400, 450, 500 and 550 °C for 3, 6 and 9 h. The produced nitrided layers were characterized concerning the microstructure, phase composition, microhardness and surface roughness. The samples were tested by ball-on-flat reciprocating dry sliding for friction coefficient and wear analysis. The tests were stopped after a given damage criteria involving the rapid growth of the friction coefficients and wear. The correlation of the different treatment parameters and resulting case depths and surface hardness with sliding distance at the time of microcracks formation or delamination of the surface layer was evaluated statistically by the analysis of variance (ANOVA). The plasm...
Currently, one of the major challenges for automotive industries is to reduce the weight and ener... more Currently, one of the major challenges for automotive industries is to reduce the weight and energy consumption of vehicles by using stronger and advanced low-cost materials. Conventional solutions using quenched and tempered steels not always fulfill the desired technical, economic and environmental requirements. Modern continuous cooling bainitic steels can provide a good combination of mechanical strength and toughness, being considered an excellent alternative to replace quenched and tempered martensitic steels in the manufacture of forged components. To meet the desired industry standards in highly loaded components, properties like surface hardness, fatigue strength, wear and friction resistance of these steels can be further improved by subsequent mechanical and thermochemical treatments. Therefore, this paper presents the state of the art in the use of continuous cooling bainitic steels for forging and low energy consumption surface improvement techniques such as: deep rolli...
Abstract The use of continuous cooling bainitic steels can provide a more energy efficient manufa... more Abstract The use of continuous cooling bainitic steels can provide a more energy efficient manufacturing route. However, for their use in mechanical components like gears, it is necessary to improve their surface properties without impacting the core properties to guarantee reliable mechanical performance. The effect of temperature and time on the plasma nitriding response of a DIN 18MnCrSiMo6-4 steel was investigated. The plasma nitriding was performed for 3, 6 and 9 hours, at 400, 450, 500 and 550 °C, using a gas mixture composed of 76 vol.% nitrogen and 24 vol.% hydrogen. Samples were characterized before and after plasma nitriding concerning the microstructure, hardness and microhardness, fracture toughness, phase composition and residual stress states. Based on the results presented, layer growth constants (k) for different temperatures was determined. Moreover, it could be found that 500 °C gave the best results investigated here, as higher temperature took to core and surface hardness decrease. The nitrided samples with thicker compound layers presented a fracture behavior dominated by the formation of Palmqvist cracks. X-ray phase analysis indicated the formation of biphasic compound layer on the surface of all nitrided samples. The diffusion zone presented compressive residual stresses with highest values near the surface.
Materials Research
Continuous cooling bainitic steels has been widely used in industrial processes owing to its exce... more Continuous cooling bainitic steels has been widely used in industrial processes owing to its excellent mechanical properties and toughness. Although the surface properties of them are acceptable for many purposes, for their use in mechanical components like gears, it is necessary to improve their surface properties. Plasma nitriding treatments was carried out of a DIN 18MnCrSiMo6-4 steel at 500 °C, with three different nitrogen gas composition: 76, 24 and 5 vol.% nitrogen in hydrogen, for 3, 6 and 9 hours. The surfaces were characterized concerning the microstructure, microhardness, fracture toughness, nitrogen concentration and carbon composition, phase composition and residual stress states. Based on the results presented, layer growth constants (k) for different nitrogen gas composition was determined. The carbon profiles of samples indicate that there was decarburization during the plasma nitriding. The nitrided samples with thicker compound layers presented a fracture behavior dominated by the formation of Palmqvist cracks. X-ray phase analysis indicated the formation of biphasic compound layer on the surface of all nitrided samples with 76 and 24 vol.% nitrogen, while the nitrided samples with 5 vol.% nitrogen indicated the formation of monophasic compound layer. The diffusion zone presented compressive residual stresses with highest values near the surface.
Matéria (Rio de Janeiro)
RESUMO Os novos aços bainíticos de resfriamento contínuo (CCBS) são uma excelente alternativa qua... more RESUMO Os novos aços bainíticos de resfriamento contínuo (CCBS) são uma excelente alternativa quando se requer elevada dureza, tenacidade e resistência à fadiga. Contudo, estima-se que a taxa de desgaste dos CCBS seja insuficiente para aplicação em componentes com alta solicitação mecânica, sendo necessário aprimorar suas propriedades de superfície. O objetivo deste estudo é o de analisar os efeitos da nitretação a plasma sobre à microestrutura e propriedades de desgaste do aço bainítico de resfriamento contínuo DIN18MnCrSiMo6-4. Portanto, tratamentos com duração de 6 horas foram conduzidos com pressão de 3 mbar, mistura gasosa composta por 76% N2 + 24% H2, e temperaturas de 400, 450, 500 e 550 °C, respectivamente. As amostras foram analisadas através de microscopia eletrônica de varredura, difração de raios-X, microdureza e ensaios de desgaste por deslizamento recíproco. Nas condições investigadas, foi possível obter uma camada de compostos e atingir um aumento de até 393% na durez...
Journal of Mechanics Engineering and Automation, Feb 28, 2018
CAE (computer aided engineering) evaluates the forging process virtually to optimize the industri... more CAE (computer aided engineering) evaluates the forging process virtually to optimize the industrial production. The numerical and experimental investigations of forging process of a hollow part are important in industrial point of view. This study has been focused on the development of a 3D elastic-plastic FEM (finite element model) of hot forging to evaluate the forming process of hollow parts. The validity of this method was verified through a laboratory experiment using aluminum alloy (AA6351) with medium geometric complexity. The distributions of effective strain, temperature, metal flow and strength were analyzed for two different initial workpieces (tubular and cylindrical). It was observed that both initial workpieces can be used to produce the final hollow part using the numerical simulation model. The results showed that the numerical analyses predict, filling cavity, calculated strength, work temperature and material flow were in agreement with the experimental results. However, some problems such as air trapping in the die causing incomplete filling could not be predicted and this problem was resolved experimentally by drilling small holes for air release in the dies.
A engenharia de produção na contemporaneidade, Dec 9, 2018
Engenharia de produção. I. Título. CDD 658.5 Elaborado por Maurício Amormino Júnior-CRB6/2422 O c... more Engenharia de produção. I. Título. CDD 658.5 Elaborado por Maurício Amormino Júnior-CRB6/2422 O conteúdo dos artigos e seus dados em sua forma, correção e confiabilidade são de responsabilidade exclusiva dos autores. 2018 Permitido o download da obra e o compartilhamento desde que sejam atribuídos créditos aos autores, mas sem a possibilidade de alterá-la de nenhuma forma ou utilizá-la para fins comerciais.
10º Congresso Brasileiro de Engenharia de Fabricação
International Journal of Engineering & Technology, 2016
The use of DOMEX 700 MCTM steel weldments is still little explored, due to some concern of the va... more The use of DOMEX 700 MCTM steel weldments is still little explored, due to some concern of the validity of the rules imposed by several standards and Codes for this class of steel. This material has low ductility and consequently the relation between tensile strength and yield strength is significantly lower than ordinary structural steels. For this reason, the instability phenomena are more critical than the instability phenomena of ordinary structural steels. Therefore, the aim of this study was to obtain detailed data on the mechanical efficiency of joints welded by GMAW. Six different heat inputs were used on square tubular profiles of TMCP steel. The tubular profiles were placed as a column/beam weldment with transverse and longitudinal welds positioned in relation to the loading axis. Twelve welded structures were instrumented with extensometer and tested in simple bending. Comparing the obtained data, it was verified that longitudinal welded joints presented higher bending st...
Soldagem & Inspeção, Mar 1, 2016
Este é um artigo publicado em acesso aberto (Open Access) sob a licença Creative Commons Attribut... more Este é um artigo publicado em acesso aberto (Open Access) sob a licença Creative Commons Attribution Non-Commercial, que permite uso, distribuição e reprodução em qualquer meio, sem restrições desde que sem fins comerciais e que o trabalho original seja corretamente citado.
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Papers by Rafael Luciano Dalcin