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1

Lignin-based polyurethane and epoxy adhesives: a short review

dos Santos D.J., Tavares L.B., Gouveia J.R., Batalha G.F.

Archives of Materials Science and Engineering

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2021

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Vol. 107, nr 2

56--63

EN

Purpose: of this paper was to review and summarize significant papers related to the development and characterization of lignin-containing adhesives: polyurethane and epoxy types. In the last decades, several efforts have been dedicated on the development of renewable raw materials for polymer synthesis, mainly due to petroleum depletion and sustainability. In this context, lignin emerged as a potential candidate to substitute fossil-based raw materials in adhesive synthesis and formulations. Design/methodology/approach: Recent and other relevant papers were reviewed, aiming to identify the main advantages and limitations involved in lignin incorporation into epoxy and polyurethane adhesives formulations. First, effects of unmodified lignin addition were presented. Afterwards, the main lignin chemical modification methods were presented and discussed, based on thermomechanical results. Findings: Incorporation of unmodified lignin usually is limited to 30 %wt., otherwise mechanical properties are drastically affected as consequence of poor lignin solubility and excessive brittleness. Lignin chemical modification can be used to increase the reactivity of hydroxyl groups and/or add new moieties in its molecular structure, improving solubility and thermomechanical properties of cured adhesives. Practical implications: In the last years, some industrial plants started to operate and produce technical grade lignin at industrial scale, with reproducible properties and controlled molecular structure. Therefore, increasing efforts have been dedicated from researchers and chemists to develop lignin-based technologies, in which this work can directly contribute with. Originality/value: As consequence of the high content of phenol groups in its molecular structure, lignin was mostly applied on the development of phenolic resins applied as wood adhesives. For the first time in the literature, this work summarizes the advances related to synthesis and characterization of polyurethane and epoxy, applied as adhesives. Results can support the development and application of biobased, as well as contribute to the revalorization of this valuable and readily available biomass.

2

Bio-based polyurethane applied as matrix of fiberglass reinforced composite

de Sousa Jr. R. R., Miranda E. A., Batalha G. F., dos Santos D. J.

Journal of Achievements in Materials and Manufacturing Engineering

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2017

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Vol. 81, nr 1

5--10

EN

Purpose: of this paper was to develop and to characterize the mechanical behaviour of a structural composite obtained from a bio-based polyurethane matrix reinforced with fiberglass. Design/methodology/approach: Castor oil and Kraft lignin-containing polyol was applied for bio-based polyurethane synthesis. Structural composite was obtained by reinforcing this renewable source bio-based polymer with fiberglass mat. Polyester resin composite was also obtained for comparison, following the same process and reinforcement conditions. Mechanical characterization was carried out through uniaxial tensile, flexural strength, Izod impact tests and additionally scanning electron microscopy (MEV). Findings: Bio-based polyurethane composite was obtained and presented higher ultimate tensile strength (UTS) and equivalent impact resistance in comparison to polyester matrix composite. Research limitations/implications: Effects of Kraft lignin and fiberglass contents changing on mechanical properties might be investigated in future researches. Practical implications: Revalorization of Kraft lignin. 50 million tons of lignin are produced worldwide every year as by-product of pulp and paper manufacturing. The most part of this Kraft lignin is currently burned for energy generation. Originality/value: Results indicated the possibility of reusing this industrial wasted by-product at large scale as polymeric matrix for structural composite, in which high UTS and impact resistance are required.

3

Systematic study of Ethylene-Vinyl Acetate (EVA) in the manufacturing of protector devices for the orofacial system

Dias R. B., Coto N. P., Batalha G. F., Driemeier L.

Archives of Materials Science and Engineering

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2017

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Vol. 86, nr 1

24--31

EN

Purpose: This study aims to provide a systematic evaluation of the EVA application in orofacial protectors while focusing on sports. Design/methodology/approach: The research comprises a numerical analysis. During experimental tests, EVA was analysed in special more specific studies about its influence on the mechanical behaviour of EVA were performed. In the numerical analyses of the EVA orofacial protector, the studies focused on its effect in the zygomatic bone protection, in a simplified geometry. Findings: According to the experimental and numerical results from a systematic study of EVA, its application to orofacial protection can be considered satisfactory. Research limitations/implications: The limitations for this research is the complex geometry of the face, number of materials and parameters involved in this study. Practical implications: For facial protection, a better performance is obtained with a combination of rigid and soft EVA material. Particularly for the zygomatic bone, a 3 mm thick plate of soft EVA overlapped by a 1 mm thick plate of rigid EVA is indicated. Originality/value: The studies made for this researchers group show that the EVA use in facial protection for sports is effective.

4

Orthotropic yield criterion for Ti-6Al-4V titanium alloy after friction stir processing (FSP)

Farias A., Delijaicov S., Bordinassi E. C., Batalha M. H. F., Batalha G. F.

Archives of Materials Science and Engineering

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2015

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Vol. 72, nr 1

33--45

EN

Purpose: This works aims at applying friction stir processing (FSP) to Ti-6Al-4V titanium alloy. Derived from friction stir welding (FSW), it is a recent process developed in the 1990s for aluminum joining. Its application to other types of materials such as steel and high performance alloys, in particular titanium, has interested industry. Design/methodology/approach: The methodology applied to evaluate FSP in this work consisted in tensile testing Ti-6Al-4V sheets in mixed conditions. The workpieces were processed in a conventional CNC milling machine with special fixture devices. Findings: A contribution to the modeling of anisotropic materials yield stress is proposed based on an orthotropic yield criterion. Additional equations based on the mixed tests for tensile and shear loadings are proposed to modify the former Cazacu orthotropic model. Research limitations/implications: Although the application limit for the model appears to be small, sheet forming process similar to those used in this work, are predominantly in the region of this analysis. Practical implications: The purpose of the model is to indicate the conditions under which the material has reached its yield regime, and may be a basis for practical simulations in similar conditions. Originality/value: The purpose of this model is to indicate the conditions under which the material has reached its yield regime, and may be a basis for practical simulations in similar conditions.

5

Mechanical and physical properties investigation of polyurethane material obtained from renewable natural source

Santos dos D J, Tavares L B, Batalha G. F.

Journal of Achievements in Materials and Manufacturing Engineering

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2012

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Vol. 54, nr 2

211--217

EN

Purpose: The purpose of this paper is to investigate the influence of different polyol/diisocyanate ratios on the mechanical and physical behaviours of polyurethane based polymers. Design/methodology/approach: Castor oil was mixed, as polyol, to diisocyanate in order to obtain polyurethane based polymers. Besides the ideal stoichiometry, polyol/ diisiocyanate ratio, ratios with excess/ lack of diisocyanates were provided. The mechanical behaviour was investigated by uniaxial tests. Differential Scanning Calorimetry (DSC) and Thermo gravimetric Analysis (TGA) were used to investigate the thermal behaviour. The various polymeric structures, obtained by the different ratios, were analysed and compared by Infrared Spectroscopy (IR). Findings: Mechanical performance was increased proportionally to contend of diisocyanate. High levels of diisocyanate have generated elongation decreasing and CO2 formation during curing, damaging mechanical behaviour due to bubble presence. Analytical experiments have showed important changes on: polymeric structures, glass transition temperatures and behaviour at elevated temperatures. Research limitations/implications: Free acid and water contend were not taken into consideration by defining the ideal stoichiometry. The investigated formulations cannot be direct applied on practical applications; fillers and additives must be added to them, which were not taken in consideration. Practical implications: The obtained results can support development of adhesives, engineering polymers and polymeric matrix for structural composites. Stabling the relation between component ratios to their behaviours is possible to define optimal performance ranges and to avoid excess of diisocyanate on polymers. Originality/value: Deep investigation of PU based material, obtained from renewable natural source (castor oil). The results can orientate development of materials for industrial applications and researches using other oils as polyol.

6

Evaluation of an AICrN coated FSW tool

Batalha G. F., Farias A., Magnabosco R, Delijaicov S., Adamiak M., Dobrzański L.A.

Journal of Achievements in Materials and Manufacturing Engineering

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2012

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Vol. 55, nr 2

607--615

EN

Purpose: This paper aims to evaluate the wear performance of a physical vapor deposition (PVD) coating on cemented carbide (WC) tool used in friction stir welding FSW processing of Ti alloy sheets. Design/methodology/approach: A coating of AlCrN material was applied to a WC tool in order to increase its wear resistance, thermal shock stability and hot hardness. In comparison to the conventional coatings, the AlCrN coating system had a higher resistance to abrasive wear as well as higher hot hardness and oxidation resistance. FSW processing of Ti with a coated WC tool was expected to have better performance than an uncoated tool. Back Scattering Electron (BSE) imaging mode at scanning electron microscope was used to determine the main mechanism of tool wear, which was found to be hot adhesion and inter-diffusion of tool constituents with the workpiece materials. Findings: The tool degradation was evaluated by scanning electron microscopy in order to observe the main tool wear mechanism. The real contribution of the (Al,Cr)N coating layer could not be correctly evaluated, since there is no residual trace of its components at the worn tool. What was probably found left from the coating layer was the N component which formed the nitride TiN observed by EDS mapping. The parameter conditions were probably too severe, overcoming the layer limit strength. Research limitations/implications: The research were carried out as a preliminary evaluation and this initial results in the need of a further analysis that should be performed looking for a suitable tool material and coating optimization for the FSW processing of titanium alloys. Practical implications: Despite being successfully used in other manufacturing applications like machining operations in which friction and temperature are also high, the WC tool material and the coating had an unsatisfactory wear resistance, and the AlCrN coating was totally worn during the FSW processing. This suggests that new materials and coatings are still needed for FSW tools. Originality/value: FSW process is gaining importance as an industrial joining method, but the tool wear is still an important challenge to achieve efficient and economic operation. Because of the low thermal conductivity and high chemical reactivity of Ti, tools wear rapidly due to high temperature and strong adhesion. In order to achieve higher processing speeds, reducing heat at the interface tool/work material is required, as is the use of tool materials that have little or no chemical affinity.

7

Practical methodology to evaluate the fatigue life of seam welded joints

Goes K. C., Batalha G. F., Pereira M. V., Camarao A. F.

Journal of Achievements in Materials and Manufacturing Engineering

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2011

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Vol. 49, nr 1

35--41

EN

Purpose: of this paper is to present a practical and robust methodology developed to evaluate the fatigue life of seam welded joints under combined cyclic loading. Design/methodology/approach: Fatigue analysis was conducted in virtual environment. The finite element stress results from each loading were imported to fatigue code FE-Fatigue and combined to perform the fatigue life prediction using the S x N (stress x life) method. A tube-to-plate specimen was submitted to a combined cyclic loading (bending and torsion) with constant amplitude. The virtual durability analysis result was calibrated based on these laboratory tests and design codes such as BS7608 and Eurocode 3. The feasibility and application of the proposed numerical-experimental methodology and contributions for the technical development are discussed. Major challenges associated with this modelling and improvement proposals are finally presented. Findings: The finite element model was validated due to laboratory results. The analytical stress result presented upper value due to the approach used that considered the fillet weld supported all work. The model presented a good representation of failure and load correlation. Research limitations/implications: The measurement or modelling of the residual stresses resulting from the welding process was not included in this work. However, the thermal and metallurgical effects, such as distortions and residual stresses, were considered indirectly with regard to the corrections performed in the fatigue curves obtained from the investigated samples. Practical implications: Integrating fatigue analysis and finite elements, it is possible to analyse several welded joint configurations in the design phase, providing development time and cost reduction, increasing the project reliability. Originality/value: This methodology will permit, in further studies, the modelling of both stresses, in-service and residual stresses, acting together, which seem like an advantage to engineers and researchers who work in design and evaluation of structural components against fatigue failures.

8

Experimental study of influence factors on compression stress relaxation of ACM

Santos dos D J, Tavares L B, Batalha G. F.

Journal of Achievements in Materials and Manufacturing Engineering

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2011

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Vol. 46, nr 1

33--39

EN

Purpose: Purpose: of this paper is to investigate the influence of electron beam (EB) radiation, temperature and deformation on the compression stress relaxation behavior of UV curing polyacrylate rubber (ACM). Design/methodology/approach: ACM plugs were obtained by UV radiation curing. Some samples were post cured by EB dose of 250 kGy, providing two material conditions. The plugs were submitted to compression stress relaxation experiments (CSR) for 5.000 min on two temperature levels, 23°C and 90°C, and deformation levels of 10% and 15%. Results were analyzed using 2k Factorial Design, quantifying the influence of these factors on the maintained compression force. Findings: The results have shown an increase in the maintained compression force, respectively a decrease in the compression stress relaxation, for all EB irradiated ACM specimens along the entire measured period of time. The increase of the three analyzed factors has caused an increase of the maintained compression force. Through the 2k Factorial Design was possible to find out the deformation as the most relevant influence factor, followed by irradiation, as second influence factor and temperature. Research limitations/implications: ACM molecular structures were not physical-chemically investigated. Therefore, possible molecular structural changes, caused by EB radiation, were not described. Practical implications: Decreasing of compression stress relaxation implicates on increasing working life of sealing components made from the studied material, besides the improvement of sealing capacity of these components, even under reduced deformation conditions. Originality/value: The use of EB radiation as successful method to decrease compression stress relaxation of UV curing ACM rubber, has opened opportunities to industrial applications. Thus, provide knowledge about influence factors on ACM relaxation behavior.

9

Mechanical behaviour characterizing and simulation of polyacrylate rubber

Santos dos D., Batalha G. F.

Journal of Achievements in Materials and Manufacturing Engineering

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2010

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Vol. 38, nr 1

33-40

EN

Purpose: of this paper is to investigate the influence of EB radiation on the mechanical behaviour of UV curing polyacrylate rubber (ACM) and to simulate its behaviour. Design/methodology/approach: The material was irradiated by two different EB doses, 100 kGy and 250 kGy, its mechanical behaviour was investigated with the help of uniaxial, equibiaxial and planar shear experiments. The results were applied to the Ogden’s Model (1972) in order to obtain the parameters to simulate the material behaviour by finite element method (FEM) and to compare experimental and FEM curves. The structure molecular changes caused by EB were investigated with the help of infrared spectroscopy. Findings: In most cases the experimental results showed an increase in the strength at rupture and a decrease in the elongation at the rupture with increasing of radiation dose. Equibiaxial and planar shear tests presented similar behaviour like uniaxial results, in terms of elongation decrease and strength increase, with some deviations. Ogden’s Model third order provided simulated curves with similar behaviour in comparison to experimental curves. The infrared spectroscopy showed different chemical group contents in the analyzed regions, surface and middle region. Research limitations/implications: Two doses of EB radiation were applied; higher or lower doses were not investigated. Practical implications: Improved behaviour of UV curing ACM can extend the range of industrial applications, or improve its performance in known applications. Originality/value: Usually EB radiation has been used to modify polymeric structure and to improve thermal and mechanical polymers behaviour. Regarding like rubber materials EB is usually applied as an alternative form of vulcanization. UV is a new type of curing for polyacrylate rubbers, which are usually cured by thermal processes.

10

Creep age forming: a short review of fundaments and applications

Ribeiro F. C., Marinho E. P., Inforzato D. J., Costa P. R., Batalha G. F.

Journal of Achievements in Materials and Manufacturing Engineering

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2010

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Vol. 43, nr 1

353--361

EN

Purpose: The aim is to review creep age forming theoretical fundaments as well as some of our experimental results. Design/methodology/approach: The approach consists of a brief review from basic theoretical concepts of creep and ageing processesincluding a description of anumeric closed form technique to predicting springback in creep age forming. Finally, a work flow to develop a creep age forming process and its respective experimental implementationare shown. Findings: The analytical model and workflow enabled an excellent result of springback predicted value (less than 1%).Research limitations/implications: The experiments only tested simple parts. An improved model is necessary for more complex parts. Practical implications: This work permits to study the creep age forming viability of a given process planning. Originality/value: This review summarizes the main concepts of the creep age forming process and illustrates them by the application of an analytic and numerical modelling performed as a didactic experiment.

11

Integrated product and process system with continuous improvement in the auto parts industry

Silva I. B., Batalha G. F., Stipkovik Filho M., Ceccarelli F. Z., Anjos J. B., Fesz M.

Journal of Achievements in Materials and Manufacturing Engineering

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2009

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Vol. 34, nr 2

204-210

EN

Purpose: Quality systems (QS) update must be based on the enterprise organization to assure customer satisfaction, as Deming, Juran and Feigenbaum did in their time, to seek improvement processes to reach high quality performance. This way, the proposal of this paper is the development of quality system integration model of product and process with continuous improvement. Design/methodology/approach: To reach this goal, a Brazilian automotive parts quality system was improved through the Computer Integrated Manufacturing (CIM), Design for Manufacturing and Assembly (DFMA) and Lean Six Sigma (LSS) methodologies. Findings: The paper shows what the problems are during the factory quality system management. The results achieved in the studied company show the performance quality evolution through their indicators. Research limitations/implications: The article presents quality system problems of only one Brazilian plant of an automotive industry. Practical implications: Presented in this article should be a way to look for continuous improvement methods. Originality/value: The paper is supported on the authors’ practical experiences to improve the quality system at a Brazilian plant.

12

Concurrent engineering and DFMA approaches on the development of automotive panels and doors

Krumenauer F. Z., Matayoshi C. T., da Silva I. B., Filho M. S., Batalha G. F.

Journal of Achievements in Materials and Manufacturing Engineering

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2008

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Vol. 31, nr 2

690-698

EN

Purpose: The automotive industry, in countries such as Brazil, China and India, in contrast to the North American and European markets, is in full expansion. Due to the huge competition in the globalized automotive market, such countries face a challenge to continue this expansion. Especially important in order to win this battle, will be their capacities to release new products in the market faster than their competitors and with more cost efficiency, making an appropriate use of tools such as total quality management, concurrent engineering and increasing the use of innovative concepts in production and logistics [1,2]. Design/methodology/approach: According with the expose above, the aim of this work was to develop DFMA tools for an industrial real case. There several tools that could be included in the Design for Excellence (DFX) methodologies. Initially, two of those can be outstand here: Design For Manufacturing (DFM) and Design For Asse. Findings: In terms of the press shop facilities of the plant the main results, were: layout optimization, press line automation feasibility, reduced setup and increased productivity, improved racks logistic, reduced overhead, reduced stamped part scraps and resources with mechanical presses selling. In terms of the planning activities, the main results were: reduce time to market, reduce press shop machinery and die stamping investments and reduce indirect cost. Practical implications: The main proposal of concurrent engineering is to shorten a product development time through a simultaneous time implementation of the several stages of the engineering activity in parallel and under a concurrent mode offering all information required by all elements of the product life cycle. Originality/value: This paper reviews fundamental concepts in concurrent engineering and DFX aiming to discuss criteria of assembly and manufacturability regarding the development of automotive panels and doors. A more detailed presentation of the Finite Element Analysis (FEA) and Computer Aided Design (CAD) results obtained during the practical industrial case of auto body panel development are not presented here due to data confidentiality and page limitation.

13

Automotive body-in-white dimensional stability through pre-control application in the subassembly process

Sanches Jr L., Filho M. S., Batalha G. F.

Journal of Achievements in Materials and Manufacturing Engineering

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2008

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Vol. 31, nr 2

705-711

EN

Purpose: This paper presents a case study and results of a pre-control method that allows for detecting subassemblies variations with low investments using a methodology that search an improvement in quality of automotive body in white assemblies joining processes through dimensional control. Design/methodology/approach: Its main contribution is the statement of pre-control method to manage the weld assembly process since the early step of the project implementation just up to the production phase. However the pre-control method didn't substitute any other dimensional control, the scope here was to demonstrate that such alternative method offers a reliable in control process of the dimensional changes and their repeatability, as it only complement the current methods used in the automotive industry. It is emphasized here the dimensional control as well as some process quality tools. Findings: It is showed the results and impact of a pre-control method in the weld assembly process, highlighting dimensional stability improvements and annual cost reduction through reducing rework hours and scrap parts quantity. Practical implications: The pre-control, revealed as a simplified tool application and can be used by the production operators with low investment cost and operation. Originality/value: The application the pre-control method is more efficient in subassemblies manufactured from manual process or that allows greater interaction of the production operator.

14

Residual stresses modelling in hard turning and its correlation with the cutting forces

Batalha G. F., Delijaicov S., Aguiar J. B., Bordinassi E. C., Stipkovic Filho M.

Journal of Achievements in Materials and Manufacturing Engineering

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2007

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Vol. 24, nr 1

350-356

EN

Purpose: This paper aims to study the cutting parameters influence (cutting speed, feed rate, cutting depth and tool radius nose) on the cutting forces (cutting force, feed rate cutting force and penetration cutting force) as well as on the residual stresses, in conical bearings made of steel DIN 100 CrMn6 hardened (62 HRc), searching correlations between the residual stresses and the cutting forces. Design/methodology/approach: A complete factorial planning was used to establish the correlations. At the same time, the cutting parameters influence in the microstructure of the material and it's correlation with the residual stress was studied. A turning center machine and CBN inserts was employed for the tests. To the cutting force measurements was carried out using a piezoelectric dynamometer. The residual stresses measurements were carried out by X-ray diffractometry. Findings: The penetration cutting force was the most important factor in the residual stress generation, and it was influenced by the feed rate and the cutting depth. A correlation between the cutting depth and the residual stresses was established. The results do not showed any changes in the microstructure of the material, even when the greater cutting parameters were used. Research limitations/implications: The residual stress is one of the major causes of failures in bearings by contact fatigue, keeping this on mind, this work helps the developer to select correct cutting parameters in order to increase the machined workpiece life in service. Originality/value: This work were based on the real components (conical bearings), real cutting conditions and with these results were possible to make greater improvements in the manufacturing and in the quality of the studied parts.

15

Superficial integrity analysis in a super duplex stainless steel after turning

Bordinassi E. C., Stipkovic M. F., Batalha G. F., Delijaicov S., Lima de N. B.

Journal of Achievements in Materials and Manufacturing Engineering

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2006

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Vol. 18, nr 1-2

335--338

EN

Purpose: Purpose of this paper was to study the main effects of the turning in the superficial integrity of the duplex stainless steel ASTM A890-Gr6A. Design/methodology/approach: The focus of the work was the finishing operations and a complete factorial planning was used, with 2 levels and 5 factors. The tests were conducted on a turning center with carbide tools and the main entrances variables were: tool material class, feed rate, cutting depth, cutting speed and cutting fluid utilization. The answers analyzed were: micro structural analysis by optical microscopy and x-ray diffraction, cutting forces measurements by a piezoelectric dynamometer, surface roughness, residual stress by x-ray diffraction technique and the micro-hardness measurements. Findings: The results do not showed any changes in the micro structural of the material, even when the greater cutting parameters were used. All the other answers were correlated with the cutting parameters and its better combination was founded for the best superficial integrity. The smaller feed rate (0.1 mm/v), smaller cutting speed (110 m/min) and the greater cutting depth (0.5 mm) provided the smaller values for the tensile residua stress, the smaller surface roughness and the greater micro-hardness. Research limitations/implications: The correlation between all the answers was very difficult to analyze because there was great interaction between the factors, but for some data group it was possible. Originality/value: The paper contribute for the study of the super duplex stainless steel, considering that no one researches was founded for the studied topics in this material in witch presents different behavior in machining when compared with another stainless steels.