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Analysis of surface integrity for din 100cr6 steel conical bearing rings after hard turning
(2011-11-12) Sergio Delijaicov; SALAZAR, C. E. V.; BORDINASSI, E. C.; PADOVESE, L. R.
This work studies the influence of machining parameters, such as cutting speed and forces, feed rate, cutting depth, and tool flank wear, on the generation of surface residual stresses in DIN 100Cr6 steel conical bearing rings submitted to a hard turning process. A complete factorial planning was used to perform the tests and projected measurement. Cutting forces were measured by a piezoelectric dynamometer and residual stresses were determined by the hole-drilling method using strain gage. Results showed that after 2000 m of tool machining, phase transformations had been observed on sample surfaces, with white layer formation, and deeper, a dark layer whose thickness varied depending on the severity level of turning and the tool wear (in machined distance). Increase in tool wear generated minor values of compressive residual stresses and the surface roughness presented almost the same values in all experiments, except when the bigger parameters were used. © (2011) Trans Tech Publication.
Comparação entre ferramentas para furação de polímeros reforçados por fibra de vidro
(2006-04-05) BATALHA, G. F.; STIPKOVIC FILHO, M.; Sergio Delijaicov; Ed Claudio Bordinassi
Para obter furos de boa qualidade em matrizes termofixas reforçadas com fibra de vidro, deve-se reduzir a força axial e o torque durante a furação. O estudo experimental relatado neste artigo avalia o desempenho e aponta a influência de quatro tipos de ferramentas (brocas helicoidais de aço rápido, serra de copo comum, serra de copo diamantada e trepanadora com insertos de metal duro) sobre estes parâmetros. Com base em um planejamento estatístico dos experimentos e na análise de variância, é possível avaliar esses fatores individualmente, seus efeitos de interação e os respectivos níveis de significância.
Correction to: Superficial residual stress, microstructure, and efficiency in similar joints of AA2024-T3 and AA7475-T761 aluminum alloys formed by friction stir welding (The International Journal of Advanced Manufacturing Technology, (2021), 116, 1-2, (117-136), 10.1007/s00170-021-07238-5)
(2021-09-05) PERANDINI, J. P. B.; Ed Claudio Bordinassi; BATALHA, M. H. F.; CARUNCHIO, A. F.; Sergio Delijaicov
© 2021, Springer-Verlag London Ltd., part of Springer Nature.The original article contained a mistake. The Figs. 14 and 15 are the same. The Fig. 14 needs to be changed to: (Figure presented.). The Figs. 16 and 17 are the same. The Fig. 16 needs to be changed to: (Figure presented.). The original article has been corrected.
Device for Measuring Efforts Generated by Tire in Steering Conditions
(2018-09-03) CHICUTA, W.; AFONSO, B.; Roberto Bortolussi; Sergio Delijaicov
© 2018 SAE International. All Rights Reserved.Currently, large companies as well as universities have increased the studies into vehicular dynamic behavior, mainly in order to improve driver and passenger safety. Simulations with complete model vehicle have been used for these studies. The tire is one of the most important vehicular component as the only connection with the ground and responsible for transmitting all vertical, longitudinal and lateral forces, consequenetly it is the main component on the model vehicle, being crucial for the correlation between computer simulations results and field tests, This paper presents a methodology, development and construction of a device to obtain lateral forces in any combination of toe and camber angles for different conditions of normal load, the tests can be performed on any type of ground, whether dry or wet. The tire datas used as reference were obtained through an experimental test using "Flat Trac" equipment. Based on these data, the components used to measuare the tire force, were developed. After the device construction, bench tests were performed in order to validate all project assumptions and calibrate the device. Finally, the device was installed on a small truck and a verification test were performed.
Effect of hybrid manufacturing (am-machining) on the residual stress and pitting corrosion resistance of 316L stainless steel
(2022-10-05) Ed Claudio Bordinassi; MHURCHADHA, S. U.; SERIACOPI, V.; Sergio Delijaicov; LEBRÃO, S. M. G.; THOMAS, K.; BATALHA, K.; RAGHAVENDRA, R.
© 2022, The Author(s), under exclusive licence to The Brazilian Society of Mechanical Sciences and Engineering.The use of additive manufacturing (AM) has grown exponentially in recent years and has many advantages, including feasibility, over other conventional processes in many current applications. The use of a second process, for example, machining, improves the surface finish and in this case, the use of two processes is known as hybrid manufacturing. Heat treatments are often performed on parts generated by the AM process, mainly to relieve the residual stresses generated, but for some materials, this can decrease the pitting corrosion resistance of the parts. The objective of this study is to analyze the effect of hybrid manufacturing (AM + machining) on residual stresses and pitting resistance corrosion, which can bring advantages to piece properties without the use of heat treatment. 316L stainless steel parts are generated by direct laser metal sintering (DLMS), with subsequent milling using a complete factorial planning for the design of the experiments. The cutting speed, feed rate, cutting depth, use of the cutting fluid and laser power in the DLMS process are all varied. Residual stresses are measured by X-ray diffraction and the blind hole method, with polarization curves raised by a potentiostat. The results show that it is possible to reduce the residual surface stresses in the parts, even for compressive stresses, and to improve the pitting corrosion resistance, when compared to the part without milling, depending on the cutting parameters used.
Impacto nas Propriedades Mecânicas e Tensões Residuais do Material ASTM A572 Grau 50 Soldado por Arco Submerso com Alívio de Tensões Térmico
(2019-10-29) VIEIRA, FERNANDO DIAS; AL-RUBAIE, KASSIM SHAMIL FADHIL; PRETI, ORLANDO; RICHTER, RINGO OTTMAR; Sergio Delijaicov
O aço ASTM A572 Grau 50 é utilizado na fabricação de conjuntos soldados para aerogeradores, por este motivo, a realização de alívio de tensões é de grande importância para correção dos impactos causados pelos processos de soldagem, bem como, o conhecimento das propriedades finais obtidas com a realização deste processo. O objetivo desse estudo é comparar as propriedades mecânicas e tensões residuais (método de furo cego) em amostras de aço ASTM A572 Grau 50, soldadas pelo processo de arco submerso, submetidas ao alívio de tensões na condição térmica (PWHT) e na condição como soldado (SST), seguindo os requisitos normativos da AWS D1.1-2015. Os resultados da condição PWHT referente a dureza, limite de escoamento, resistência a tração e tensões residuais são menores e os valores de alongamento e energia absorvida ao impacto são maiores do que a condição SST. Ambas as condições foram aprovadas no ensaio de dobramento lateral. Os resultados obtidos demonstram a importância do processo de alivio de tensões que minimiza os efeitos indesejados dos processos de soldagem aos componentes.
Influence in the mechanical properties and residual stresses of ASTM A572 grade 50 material welded by submerged arc welding with post weld heat treatment Impacto nas propriedades mecânicas e tensões residuais do material ASTM A572 grau 50 soldado por arco submerso com alívio de tensões térmico
(2019-12-02) VIEIRA, F. D.; AL-RUBAIE, K. S. F.; PRETI, O.; RICHTER, R. O.; DELIJAICOV, S.
© 2019, Universidade Federal de Uberlandia. All rights reserved.The ASTM A572 Grade 50 material is used in welded structural components in the manufacture of wind turbines. In this way, it is important to apply the stress relief process to correct the effects caused by the welding processes, and then assess the final properties obtained with this process. The objective of this article is to evaluate the mechanical properties of specimens of the ASTM A572 Grade 50 material welded by the submerged arc welding, comparing the thermal stress relief condition (PWHT) with the as welded condition (SST), following the normative requirements of AWS D1. 1-2015. Tensile testing, impact test, lateral bending, hardness and residual stresses measured by hole drilling method for the conditions tested. The results showed lower values of hardness, residual stress, yield strength, and ultimate tensile strength of the PWHT specimens. On the other hand, the values of elongation and impact energy absorbed of the PWHT specimens were higher than those of the SST specimens. Both conditions tested were approved in the lateral bending test. The results demonstrate the importance of the stress relief process, which reduces the unwanted effects of the welding processes, thereby delivering better quality of the components.
Investigation of residual stress in laser welding dissimilar materials Investigação da tensão residual na soldagem laser de mate riais dissimilares
(2010-07-26) MIRIM, D. DE C.; BERRETTA, J. R.; ROSSI, W. DE; LIMA, N. B. DE; OLIVEIRA, R. R. DE; Sergio Delijaicov; GOMES, D. O.
One of the most critical problems found in the different materials welding is the residual stress formation, that happens mainly for the fact of those materials they possess coefficients of thermal expansion and different thermal conductivities. Like this in this work the residual tension was evaluated in the technique of welding laser among the steel low carbon, AISI 1010 and AISI 304. The materials were united for it welds autogenous of top with a laser of continuous Nd:YAG in that they were varied the potency, speed and the focus of the laser stayed constant in relation to surface of the sample. The main objective of the study went identification and to analysis of the residual stress in HAZ on both sides of seem. Um planning factorial of two factors at two levels each it was executed for optimization the combination of the factors potency and speed. The obtained answers were the residual stress in different depths in HAZ. In the surface of the sample measures of residual stress were accomplished by the technique of X-ray difraction. The hole drilling strain gage method it was applied to measure the residual stress on both sides of the union. The results were analyzed using the variance analysis and the statistical regression based on the different influences of the entrance and combination of the factors in the residual stress generated in that union. The results indicate that the development of models can foresee the answers satisfactorily.
Microhardness and residual stress of dissimilar and thick aluminum plates AA7181-T7651 and AA7475-T7351 using bobbin, top, bottom, and double-sided FSW methods
(2020-05-12) Sergio Delijaicov; RODRIGUES, M.; FARIAS, A.; NEVES, M. D.; Roberto Bortolussi; MIYAZAKI, M.; BRANDÃO, F.
Friction stir welding (FSW) is a relatively new manufacturing process (invented in 1991 at the Welding Institute, UK) and more than 5000 scientific articles have been published in the past 10 years in indexed journals demonstrating the robustness of the research. However, further research is necessary to ensure safe use of the technique for structural components, particularly with reference to the aeronautics industry. Residual stresses and their consequences on the life of welded products must be fully understood, in addition to their correlations with other properties such as hardness, strength, and microstructure. This paper is a part of the research being conducted to evaluate the impact of four FSW techniques (bobbin, top-sided, bottom-sided, and doublesided) on the mechanical properties in dissimilar thick joints (12.7 mm) of aluminum alloys (AA7181-T7651 and AA7475- T7351) used in the aeronautics industry. The residual stresses were measured using the incremental blind hole technique and analyzed using the integral method. The longitudinal residual stresses were all positive, with values between 100 and 200 MPa in the stir zone, whereas the transverse ones were all negative, with values between 0 and − 100 MPa. It was possible to verify that the Bobbin process produced lower values of residual stresses and demonstrated better stability in its distribution compared to all the other FSW methods tested.
Modeling stick-slip in bolted joint tightening process
(2020-04-09) FERNANDES, RAUL DE SOUSA; Roberto Bortolussi; Sergio Delijaicov; FERREIRA, JEFERSON
Stick-slip affects torque-preload relationship during bolted joint tightening process. Its occurrence is not always possible to avoid and it can lead to an unreliable joint. In this study, tightening process was investigated and, in a first approach, modeled through theoretical analysis. In a second approach, experimental data was explored statistically using Analysis of Variance (ANOVA) and F-Test. Coefficient of global friction and stick-slip pa-rameters were modeled and added to the first model. The final semi-empirical model was able to reproduce the variation of the friction and to predict stick-slip occurrence. Low errors were obtained in the comparison with experimental data for both cases, with and without the occurrence of stick-slip. The proposed semi-empirical model provides mathematical approach for accurately predicting stick-slip and its characteristics in a specific condition of bolt-nut surface treatment.
Residual compressive stresses applied due to shot peening process in the Ti 6al 4v alloy
(2010-07-26) LAVOR, P. R. U.; MOURA-NETO, C. DE; Sergio Delijaicov; DE CAMPOS, V. S.
The objective is to measure the residual stresses in the Ti 6Al 4V alloy due the shot peening process. The specimens were manufactured in the conditions: 1st machined without Shot Peening; 2nd machined and submitted to Shot Peening in the range: 0,13 N(mm) - 0,46 N(mm); 3rd Machined and submitted to Shot Peening in the range: 0,15 A(mm) - 0,25 A(mm). The residual stresses were measured through the incremental hole drilling technique and the data obtained in a graphic form and are important for stress analysis in order to verify the influence of the residual stresses in the fatigue life. The graphics show the curves of the compressive tensions through the thickness of the three conditions studied and herein follows an idea of the obtained measurements: 1st Machined test specimens without shot peening application: residual compressive stresses of 200 MPa. 2 ndMachined test specimens and submitted to Shot Peening application in the range: 0.13 N(mm) - 0.46 N(mm): Residual Compressive Stresses of 500 MPa. 3rd: Machined test specimens and submitted Shot Peening application in the range: 0.15 A(mm) - 0.25 A(mm): Residual Compressive Stresses of 1000 MPa.
Residual stresses measurements using strain gages - aluminum wheels
(2012-11-06) CIONE, F. C.; ROSSI, J. L.; SOUZA, A. C.; Sergio Delijaicov; COLOSIO, M. A.
Many engineering specifications, manufacturing procedures, inspection and quality control have begun to require that the residual stress of a particular component be evaluated. This is becoming as commonplace as the demands on the mechanical properties. In the country there are few research laboratories qualified to perform these tests and also found a worrying lack of skilled labor. Studying the formation and distribution of residual stress fields will improve the operational criteria of wheel safety, among other gains. It is known that these residual stress fields could be added to the effects of system load (tare weight plus occupation of vehicle traction, braking and torque combined). The results obtained used drilling method and rosette type strain gages, are convergent with similarity to those obtained using FEA simulation over critical region for global and superficial in principal stresses mode. The relevance of the present study and research on residual stresses meets safety improvements in car's wheel industry. © (2012) Trans Tech Publications, Switzerland.
Simple machine learning allied with data-driven methods for monitoring tool wear in machining processes
(2020-08-01) FARIAS, ADALTO DE; ALMEIDA, SÉRGIO LUIZ RABELO DE; Sergio Delijaicov; SERIACOPI, VANESSA; Ed Claudio Bordinassi
The aim of this work was to identify the occurrence of machine tool wear in carbide inserts applied in a machine turning center with two steel materials. Through the data collected with an open-source communication protocol during machining, eighty trials of twenty runs each were performed using central composite design experiments, resulting in a data set of eighty lines for each tested material. The data set consisted of forty lines with the tool wear condition and forty lines without. Machining parameters were set to be in the range of the usual industrial values. The cutting parameters in the machining process were cutting speed, feed rate, cutting depth, and cutting fluid applied in the abundance condition and without cutting fluid (dry machining). The collected data were the spindle motor load, X-axis motor load, and Z-axis motor load in terms of the percentage used. AISI P20 and AISI 1045 steels workpieces were tested with both new and worn inserts, and a flank tool wear of 0.3 mm was artificially induced by machining with the same material before the data collecting experiment. Two approaches were used in order to analyze the data and create the machine learning process (MLP), in a prior analysis. The collected data set was tested without any previous treatment, with an optimal linear associative memory (OLAM) neural network, and the results showed 65% correct answers in predicting tool wear, considering 3/4 of the data set for training and 1/4 for validating. For the second approach, statistical data mining methods (DMM) and data-driven methods (DDM), known as a self-organizing deep learning method, were employed in order to increase the success ratio of the model. Both DMM and DDM applied along with the MLP OLAM neural network showed an increase in hitting the right answers to 93.8%. This model can be useful in machine monitoring using Industry 4.0 concepts, where one of the key challenges in machining components is finding the appropriate moment for a tool change.
Superficial residual stress, microstructure, and efficiency in similar joints of AA2024-T3 and AA7475-T761 aluminum alloys formed by friction stir welding
(2021-09-05) PERANDINI, J. P. B.; Ed Claudio Bordinassi; BATALHA, M. H. F.; CARUNCHIO, A. F.; Sergio Delijaicov
© 2021, The Author(s), under exclusive licence to Springer-Verlag London Ltd., part of Springer Nature.Friction stir welding (FSW) represents a conceptually simple technique that consists of joining either similar or dissimilar solid-state materials through higher plastic deformation rates. FSW is an important technique in the aeronautical and aerospace industries, and its development is vital because of the significant difficulty in joining higher resistance AA 2000 and AA 7000 aluminum alloys with conventional techniques, like fusion welding, due to porosity and mechanical property losses. Thin sheets with a 1.6-mm nominal thickness of AA2024, heat treated to condition T3, and thin sheets with a 1.6-mm nominal thickness of AA7475, heat treated to condition T761, were used to investigate the influence of welding parameters under superficial residual stress and the efficiency of joints by FSW of AA2024-T3 and AA7475-T761 aluminum alloys. A central composite design (CCD) was used as a statistical model in this study (23 factorial points, six stellar points, two central points, and two replicas). Micrographic analysis showed that in the nugget zone of the AA7475-T761 alloy, there was hardness recovery. The fractography images showed that failures occurred mainly due to the joint line remnant defect, evidenced by the presence of cracks. The superficial residual stresses show a maximum value of 81 MPa at the advancing side in run 27 (hot welding) of AA2024-T3, whereas in AA7475-T761, a value of 57 MPa was found in the same run. Finally, tensile strength represents an efficiency of ~92% of the AA2024-T3 base metal value, while for AA7475-T761, this value was ~85%. From a component design perspective, the parameter window of this study is identified as interesting for its evaluation in the possible application in component manufacturing, due to the low values of superficial residual stresses found compared to those in previous work.
Surface Integrity Analysis in Machining of Hardened AISI 4140 Steel
(2017-03-05) STIPKOVIC, M. A.; BORDINASSI, E. C.; FARIAS, A.; Sergio Delijaicov
Surface integrity analysis in machining of hardened AISI 4140 steel
(2017-01-23) STIPKOVIC, M. A.; Ed Claudio Bordinassi; Farias, Adalto; Sergio Delijaicov
This study aimed to analyze the residual stresses and roughness in finishing milling of AISI 4140 steel, quenched and tempered up to hardness of 58 HRC. Machining operations were performed with the use of CBN inserts and by varying three basic cutting parameters (cutting speed, feed per tooth and cutting depth). Hardened materials are typically machined by abrasive processes, which in turn are more expensive and complex to be studied due to the undefined cutting geometry of the grinding wheel. A series of machining tests with milling process and CBN tools was implemented in order to study the resultant condition of the specimeńs surface. An experimental design was used and the results were statistically treated, enabling the generation of a model that aims to obtain roughness values due to the optimization of three adopted cutting parameters. The roughness values found in the range of Ra 0,16 to 0,4 μm indicate that it is possible to use the milling process with CBN tools for finishing, reducing machining time and the cost of the machined part. The generated residual stresses were compressive and the feed per tooth parameter showed greater influence in this result. The research was limited to test only one type of CBN insert, which was constantly replaced, preventing the influence of tool wear on responses. The geometry of the tool as well as the use of cutting fluid were not considered. Milling process with CBN inserts is confirmed as a possibility for replacing grinding process for finishing machining leading to significant gains in machining time. An optimized model was derived to predict the value of the roughness and three optimizations were made to specify the best cutting parameters to desirable answers such as better roughness, higher compressive residual stresses and low cutting forces, for example.
Surface integrity of INCONEL 718 turned under cryogenic conditions at high cutting speeds
(2019-06-26) PEREIRA, W. H.; Sergio Delijaicov
© 2019, Springer-Verlag London Ltd., part of Springer Nature.Nickel alloys such as Inconel 718 have been widely used in the aerospace, oil and gas, and chemical industries, since they have excellent properties that combine high creep resistance and high mechanical strength, fatigue and corrosion. However, these properties make these alloys extremely difficult to machine, due to a high level of heat generation during material removal, causing rapid wear of cutting tools and a detrimental effect on the surface integrity, reducing the fatigue life of the machined component and lowering the productivity. Looking at the literature, it seemed that there is an opportunity to study the surface integrity of Inconel 718, turned under cryogenic conditions at cutting speeds of 250, 275 and 300 m/min. For these reasons, this work aims to evaluate the influence of the cutting parameters on the surface integrity of Inconel 718 turned under cryogenic conditions using liquid nitrogen (LN2) at high cutting speeds. A whisker-reinforced ceramic tool was used in order to provide wear and shock resistance at high cutting speeds; these are factors that are associated with surface integrity in terms of roughness Ra, residual stresses, microhardness and cutting forces. A central composite design was chosen as factorial planning for the independent variables including cutting speed, feed rate and depth of cut when carrying out the experiments. Cryogenic cooling resulted in an average cutting force of 267 N, where the penetration force was higher. The roughness Ra was 0.52 μm and was influenced by the feed rate and depth of cut. The highest tensile residual stresses in the circumferential direction with LN2 and under dry conditions were 1394 MPa and 1237 MPa, respectively and were influenced by the depth of cut. Small changes in microhardness occurred at a depth of 0.3 mm from beneath machine surface and the presence of a white layer was not observed. Although tensile residual stresses were slightly higher when using LN2 compared to dry machining on the surface, the use of LN2 caused higher compressive residual stresses at the subsurface, which can improve the fatigue life of machined components at high cutting speeds. The results showed that lower cutting parameters tend to give the best results in terms of the cutting force and surface integrity.
The effect of process parameters and cutting tool shape on residual stress of SAE 52100 hard turned steel by high speed machining
(2020-04-26) PASCHOALINOTO, N. W.; Ed Claudio Bordinassi; Roberto Bortolussi; Fabrizio Leonardi; Sergio Delijaicov
This study focused on determining the residual stress of SAE 52100 hard-turned steel. The objective was to evaluate and compare the effects of the cutting-edge geometry and cutting parameters (cutting speed, feed rate, and cutting depth) on the residual stresses of three different conventional inserts: S-WNGA08 0408S01020A 7025, T-WNGA08 0408T01020A 7025, and S-WNGA432S0330A 7025. Tests were performed on 60 samples of SAE 52100 hardened steel with an average hardness of 58.5 HRC. The circumferential residual stresses of the samples were measured by X-ray diffraction. A full factorial design of experiments with three factors and two levels each with two central points and a replicate was used for a statistical analysis. The most significant results were as follows: For all inserts, the measured residual stresses were compressive, which extended the tool lifespan. The residual stresses of the Type-S inserts were significantly influenced by the cutting speed and depth, and those of the Type-T insert were significantly influenced by the feed rate and cutting depth. In addition, the residual stresses of the insert 3 were more compressive than those of the other two types of inserts. In other words, residual stresses are more compressive for inserts with larger chamfer angles even as the principal residual stress profiles were all compressive. This work has also shown that it is possible to determine a significant statistical relationship between cutting forces and residual stresses, allowing force measurements to predict the residual stress without any information on process parameters.