Analise da soldagem a ponto por resistência elétrica do aço 38MnB5 estampado a quente
Autor(a) principal: | |
---|---|
Data de Publicação: | 2021 |
Tipo de documento: | Trabalho de conclusão de curso |
Idioma: | por |
Título da fonte: | Repositório Institucional da UFSCAR |
Texto Completo: | https://repositorio.ufscar.br/handle/ufscar/16021 |
Resumo: | With the increasing demand for lighter and safer vehicles one of the solutions is the use of stronger steels that can be formed by hot stamping and with smaller thicknesses, reducing weight and maintaining safety. The 38MnB5 is a steel produced for hot stamping that has the premise of reaching up to 2000 MPa of Tensile Strength depending on the cooling rate applied in the stamping process. Its microstructure after stamping is mostly composed of fine grains of martensite, which enable this high strength. Because it is a recent steel grade in the market, information about welding is still lacking, especially information about resistance spot welding, a process widely used in automotive parts. In this way, a study of resistance spot welding was performed for 38MnB5 steel, the material was characterized to define the mechanical properties initially and after the hot stamping process, where the quenching of the material is carried out. The 38MnB5 grade was hot stamped from an existing production line at Benteler Automotive, to produce the 22MnB5 grade. Because it is a hot process and because the steel used is uncoated, the oxide layer formation takes place as soon as it meets the atmosphere, during the transfer of the plate from the furnace to the stamping tool. Thus, the steel was analyzed for weldability in two different surface conditions: after stamping, containing an oxidized layer; and blasted, where the oxide layer was removed. The 8.8 kA current was the one that presented the best results regarding the size and repeatability of the welded plug. Vickers HV1 microhardness profile was determined on the weld cross section, showing values ranging from 350 to 600 HV. The macrography of the weld cross section together with the microhardness values enable the determination of the base metal, the heat-affected zone, and the fused zone. The microstructure of these weld regions varies between martensite, tempered martensite, and tempered martensite with precipitated ferrite on the pre-austenitic grain boundary. To evaluate the mechanical behavior of the joint, shear testing was performed. The rupture force reached was higher than 13.4 kN for all tested samples, where the samples with oxidation obtained lower repeatability of the results. Both presented a pull-out failure mechanism, which is the preferred mechanism for industrial processes. |
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Pallu, Lucas GomesBolfarini, Claudemirohttp://lattes.cnpq.br/9231627080617037Santana, Jéssica032c65c3-02af-404b-b930-4dfb8ff10d862022-05-04T20:20:28Z2022-05-04T20:20:28Z2021-11-12PALLU, Lucas Gomes. Analise da soldagem a ponto por resistência elétrica do aço 38MnB5 estampado a quente. 2021. Trabalho de Conclusão de Curso (Graduação em Engenharia de Materiais) – Universidade Federal de São Carlos, São Carlos, 2021. Disponível em: https://repositorio.ufscar.br/handle/ufscar/16021.https://repositorio.ufscar.br/handle/ufscar/16021With the increasing demand for lighter and safer vehicles one of the solutions is the use of stronger steels that can be formed by hot stamping and with smaller thicknesses, reducing weight and maintaining safety. The 38MnB5 is a steel produced for hot stamping that has the premise of reaching up to 2000 MPa of Tensile Strength depending on the cooling rate applied in the stamping process. Its microstructure after stamping is mostly composed of fine grains of martensite, which enable this high strength. Because it is a recent steel grade in the market, information about welding is still lacking, especially information about resistance spot welding, a process widely used in automotive parts. In this way, a study of resistance spot welding was performed for 38MnB5 steel, the material was characterized to define the mechanical properties initially and after the hot stamping process, where the quenching of the material is carried out. The 38MnB5 grade was hot stamped from an existing production line at Benteler Automotive, to produce the 22MnB5 grade. Because it is a hot process and because the steel used is uncoated, the oxide layer formation takes place as soon as it meets the atmosphere, during the transfer of the plate from the furnace to the stamping tool. Thus, the steel was analyzed for weldability in two different surface conditions: after stamping, containing an oxidized layer; and blasted, where the oxide layer was removed. The 8.8 kA current was the one that presented the best results regarding the size and repeatability of the welded plug. Vickers HV1 microhardness profile was determined on the weld cross section, showing values ranging from 350 to 600 HV. The macrography of the weld cross section together with the microhardness values enable the determination of the base metal, the heat-affected zone, and the fused zone. The microstructure of these weld regions varies between martensite, tempered martensite, and tempered martensite with precipitated ferrite on the pre-austenitic grain boundary. To evaluate the mechanical behavior of the joint, shear testing was performed. The rupture force reached was higher than 13.4 kN for all tested samples, where the samples with oxidation obtained lower repeatability of the results. Both presented a pull-out failure mechanism, which is the preferred mechanism for industrial processes.Com o aumento da demanda de veículos mais leves e mais seguros uma das soluções é a utilização de aços mais resistentes que podem ser conformados por meio da estampagem a quente e com espessuras menores, diminuindo o peso e mantendo a segurança. O 38MnB5 é um aço produzido para estampagem a quente que tem a premissa de alcançar até 2000MPa de Resistencia a Ruptura dependendo da taxa de resfriamento imposta no processo de estampagem. Sua microestrutura após estampagem é majoritariamente composta de grãos finos de martensita, que possibilitam essa alta resistência. Por ser um grau de aço recente no mercado, informações sobre soldagem ainda estão sendo estudadas, principalmente informações sobre a soldagem por resistência elétrica, processo amplamente utilizado em peças automobilísticas. Desse modo, foi realizado um estudo da soldagem por resistência elétrica para o aço 38MnB5, o material foi caracterizado a fim de definir as propriedades mecânicas iniciais e após o processo de estampagem a quente, onde ocorre a tempera do material. O grau 38MnB5 foi estampado a quente a partir de uma linha de produção já existente na Benteler Automotive, para produção do grau 22MnB5. Por ser um processo realizado a quente e uma vez que o aço utilizado não possui revestimento, a formação de camada de óxido ocorre assim que o mesmo entra em contato com a atmosfera, durante a transferência da chapa entre o forno e a ferramenta de estampagem. Assim, o aço foi analisado quanto a soldabilidade em duas condições superficiais diferente: após estampado, contendo camada oxidada; e jateado, onde a camada de óxido foi removida. A corrente de 8,8 kA foi a que apresentou os melhores resultados quanto ao tamanho e repetibilidade da lente soldada. Perfil de microdureza Vickers HV1 foi realizado na seção transversal da solda, obtendo valores que variam de 350 a 600 HV. A macrografia da seção transversal da solda junto com os valores de microdureza possibilitam a determinação das regiões do metal base, da zona termicamente afetada e da zona fundida. A microestrutura destas regiões da solda varia entre martensita, martensita revenida e martensita revenida com ferrita precipitada no contorno do grão pré-austenítico. Para avaliar o comportamento mecânico da junta, o teste de cisalhamento foi realizado. A força de ruptura alcançada foi maior que 13,4 kN para todas as amostras ensaiadas, onde as amostras com oxidação obtiveram menor repetibilidade dos resultados. Ambas apresentaram mecanismo de falha por arrancamento, que é o mecanismo preferível para processos industriais.Não recebi financiamentoporUniversidade Federal de São CarlosCâmpus São CarlosEngenharia de Materiais - EMaUFSCarAttribution-NonCommercial-NoDerivs 3.0 Brazilhttp://creativecommons.org/licenses/by-nc-nd/3.0/br/info:eu-repo/semantics/openAccessConformado quenteSolda resistênciaHot-formingResistance spot weldingPress hardenable steels38MnBENGENHARIAS::ENGENHARIA DE MATERIAIS E METALURGICA::METALURGIA DE TRANSFORMACAOAnalise da soldagem a ponto por resistência elétrica do aço 38MnB5 estampado a quenteResistance spot welding evaluation of hot formed 38MnB5 steelinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/bachelorThesis600600ea2697dd-8d22-4c7a-8bdd-487c739e04c7reponame:Repositório Institucional da UFSCARinstname:Universidade Federal de São Carlos (UFSCAR)instacron:UFSCARORIGINALLucas Gomes Pallu TCC.pdfLucas Gomes Pallu TCC.pdfapplication/pdf4698256https://repositorio.ufscar.br/bitstream/ufscar/16021/1/Lucas%20Gomes%20Pallu%20TCC.pdf57a0d74e72e7857962226adaf3544e80MD51CC-LICENSElicense_rdflicense_rdfapplication/rdf+xml; charset=utf-8811https://repositorio.ufscar.br/bitstream/ufscar/16021/2/license_rdfe39d27027a6cc9cb039ad269a5db8e34MD52TEXTLucas Gomes Pallu TCC.pdf.txtLucas Gomes Pallu TCC.pdf.txtExtracted texttext/plain87674https://repositorio.ufscar.br/bitstream/ufscar/16021/3/Lucas%20Gomes%20Pallu%20TCC.pdf.txt4157a750186a316bfdec8ff6e54c9b17MD53THUMBNAILLucas Gomes Pallu TCC.pdf.jpgLucas Gomes Pallu TCC.pdf.jpgIM Thumbnailimage/jpeg7379https://repositorio.ufscar.br/bitstream/ufscar/16021/4/Lucas%20Gomes%20Pallu%20TCC.pdf.jpgec4240cad7eb0d4a9b5f5fd60b48ce45MD54ufscar/160212023-09-18 18:32:25.489oai:repositorio.ufscar.br:ufscar/16021Repositório InstitucionalPUBhttps://repositorio.ufscar.br/oai/requestopendoar:43222023-09-18T18:32:25Repositório Institucional da UFSCAR - Universidade Federal de São Carlos (UFSCAR)false |
dc.title.por.fl_str_mv |
Analise da soldagem a ponto por resistência elétrica do aço 38MnB5 estampado a quente |
dc.title.alternative.eng.fl_str_mv |
Resistance spot welding evaluation of hot formed 38MnB5 steel |
title |
Analise da soldagem a ponto por resistência elétrica do aço 38MnB5 estampado a quente |
spellingShingle |
Analise da soldagem a ponto por resistência elétrica do aço 38MnB5 estampado a quente Pallu, Lucas Gomes Conformado quente Solda resistência Hot-forming Resistance spot welding Press hardenable steels 38MnB ENGENHARIAS::ENGENHARIA DE MATERIAIS E METALURGICA::METALURGIA DE TRANSFORMACAO |
title_short |
Analise da soldagem a ponto por resistência elétrica do aço 38MnB5 estampado a quente |
title_full |
Analise da soldagem a ponto por resistência elétrica do aço 38MnB5 estampado a quente |
title_fullStr |
Analise da soldagem a ponto por resistência elétrica do aço 38MnB5 estampado a quente |
title_full_unstemmed |
Analise da soldagem a ponto por resistência elétrica do aço 38MnB5 estampado a quente |
title_sort |
Analise da soldagem a ponto por resistência elétrica do aço 38MnB5 estampado a quente |
author |
Pallu, Lucas Gomes |
author_facet |
Pallu, Lucas Gomes |
author_role |
author |
dc.contributor.author.fl_str_mv |
Pallu, Lucas Gomes |
dc.contributor.advisor1.fl_str_mv |
Bolfarini, Claudemiro |
dc.contributor.advisor1Lattes.fl_str_mv |
http://lattes.cnpq.br/9231627080617037 |
dc.contributor.advisor-co1.fl_str_mv |
Santana, Jéssica |
dc.contributor.authorID.fl_str_mv |
032c65c3-02af-404b-b930-4dfb8ff10d86 |
contributor_str_mv |
Bolfarini, Claudemiro Santana, Jéssica |
dc.subject.por.fl_str_mv |
Conformado quente Solda resistência |
topic |
Conformado quente Solda resistência Hot-forming Resistance spot welding Press hardenable steels 38MnB ENGENHARIAS::ENGENHARIA DE MATERIAIS E METALURGICA::METALURGIA DE TRANSFORMACAO |
dc.subject.eng.fl_str_mv |
Hot-forming Resistance spot welding Press hardenable steels 38MnB |
dc.subject.cnpq.fl_str_mv |
ENGENHARIAS::ENGENHARIA DE MATERIAIS E METALURGICA::METALURGIA DE TRANSFORMACAO |
description |
With the increasing demand for lighter and safer vehicles one of the solutions is the use of stronger steels that can be formed by hot stamping and with smaller thicknesses, reducing weight and maintaining safety. The 38MnB5 is a steel produced for hot stamping that has the premise of reaching up to 2000 MPa of Tensile Strength depending on the cooling rate applied in the stamping process. Its microstructure after stamping is mostly composed of fine grains of martensite, which enable this high strength. Because it is a recent steel grade in the market, information about welding is still lacking, especially information about resistance spot welding, a process widely used in automotive parts. In this way, a study of resistance spot welding was performed for 38MnB5 steel, the material was characterized to define the mechanical properties initially and after the hot stamping process, where the quenching of the material is carried out. The 38MnB5 grade was hot stamped from an existing production line at Benteler Automotive, to produce the 22MnB5 grade. Because it is a hot process and because the steel used is uncoated, the oxide layer formation takes place as soon as it meets the atmosphere, during the transfer of the plate from the furnace to the stamping tool. Thus, the steel was analyzed for weldability in two different surface conditions: after stamping, containing an oxidized layer; and blasted, where the oxide layer was removed. The 8.8 kA current was the one that presented the best results regarding the size and repeatability of the welded plug. Vickers HV1 microhardness profile was determined on the weld cross section, showing values ranging from 350 to 600 HV. The macrography of the weld cross section together with the microhardness values enable the determination of the base metal, the heat-affected zone, and the fused zone. The microstructure of these weld regions varies between martensite, tempered martensite, and tempered martensite with precipitated ferrite on the pre-austenitic grain boundary. To evaluate the mechanical behavior of the joint, shear testing was performed. The rupture force reached was higher than 13.4 kN for all tested samples, where the samples with oxidation obtained lower repeatability of the results. Both presented a pull-out failure mechanism, which is the preferred mechanism for industrial processes. |
publishDate |
2021 |
dc.date.issued.fl_str_mv |
2021-11-12 |
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2022-05-04T20:20:28Z |
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2022-05-04T20:20:28Z |
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info:eu-repo/semantics/publishedVersion |
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info:eu-repo/semantics/bachelorThesis |
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bachelorThesis |
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PALLU, Lucas Gomes. Analise da soldagem a ponto por resistência elétrica do aço 38MnB5 estampado a quente. 2021. Trabalho de Conclusão de Curso (Graduação em Engenharia de Materiais) – Universidade Federal de São Carlos, São Carlos, 2021. Disponível em: https://repositorio.ufscar.br/handle/ufscar/16021. |
dc.identifier.uri.fl_str_mv |
https://repositorio.ufscar.br/handle/ufscar/16021 |
identifier_str_mv |
PALLU, Lucas Gomes. Analise da soldagem a ponto por resistência elétrica do aço 38MnB5 estampado a quente. 2021. Trabalho de Conclusão de Curso (Graduação em Engenharia de Materiais) – Universidade Federal de São Carlos, São Carlos, 2021. Disponível em: https://repositorio.ufscar.br/handle/ufscar/16021. |
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https://repositorio.ufscar.br/handle/ufscar/16021 |
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Attribution-NonCommercial-NoDerivs 3.0 Brazil http://creativecommons.org/licenses/by-nc-nd/3.0/br/ info:eu-repo/semantics/openAccess |
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Attribution-NonCommercial-NoDerivs 3.0 Brazil http://creativecommons.org/licenses/by-nc-nd/3.0/br/ |
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openAccess |
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Universidade Federal de São Carlos Câmpus São Carlos Engenharia de Materiais - EMa |
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UFSCar |
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Universidade Federal de São Carlos Câmpus São Carlos Engenharia de Materiais - EMa |
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