MÉTODO EXPERIMENTAL PARA DETERMINAÇÃO DOS LIMITES DE EXPANSÃO DE LATAS DE TRÊS PEÇAS
EXPERIMENTAL METHOD FOR DETERMINING THE EXPANSION LIMITS OF THREE-PIECE CANS
Campissi, Paulo Roberto; Moreira, Luciano Pessanha; Alvarez, Eric Jeronimo de O.; Viana, Carlos Sérgio da C.; Santos, Willian Ribeiro dos
http://dx.doi.org/10.4322/tmm.2011.018
Tecnol. Metal. Mater. Min., vol.8, n2, p.115-121, 2011
Resumo
Este trabalho apresenta um novo método para avaliar a conformabilidade de folhas de flandres usadas na produção de latas de três peças por expansão mecânica. Os corpos de prova são tubos soldados com grade litografada de 2,5 mm para medição das deformações nas direções meridionais e circunferenciais. Foi projetado um ferramental específico fixando-se alguns parâmetros como número e largura das pinças de expansão. O aparato é adaptado a uma máquina Erichsen, na qual o deslocamento radial do ferramental é controlado por um sistema hidráulico. Os estados de deformação são obtidos variando-se os raios das ferramentas. Os ensaios de expansão foram realizados com folha de flandres de 0,18 mm até a fratura do tubo e, em seguida, foram obtidas as deformações com um programa de correlação de imagens digitais. O ferramental de expansão proposto possibilita obter deformações limites de folhas finas revestidas de um modo simples comparado com as técnicas de Curva Limite de Conformação (CLC). Portanto, este método torna-se muito útil para desafios de inovação tecnológica e reduções de custos no mercado global de embalagens metálicas.
Palavras-chave
Embalagem, Deformação, Conformação, Folha-de-flandres
Abstract
This work presents a new method to determine the formability of thin tinplate metallic sheets used to produce three-piece cans by mechanical expansion. The specimens consist of seamed welded tubes wherein a 2.5 mm square grid was printed by lithography to measure the hoop and meridional strains. A specific expansion tooling was designed by keeping constant some parameters such as the number and the width of the tools. The device is adapted to an Erichsen testing machine, in which the tooling displacement is controlled by a hydraulic system. The strain states are achieved by varying the tooling radii. The expansion tests were performed with a tinplate sheet with 0.18 mm thickness up to the tube fracture and then, the strains were obtained with a digital image correlation software. The proposed mechanical expansion tooling allows for attaining limit strains of coated thin metal sheets in a simple way compared to the Forming Limit Curve testing techniques. Therefore, this new method turns to be very useful to the challenges of technological innovations and costs reduction in the global market of metal packaging.
Keywords
Metal packaging, Strain, Forming, Metallic sheets
Referências
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2 ASTM INTERNATIONAL. ASTM E45: 10e1 Standard test methods for determining the inclusion content of steel. West Conshohocken, 2010. http://dx.doi.org/10.1520/E0045-10E01
3 ASTM INTERNATIONAL. ASTM E112: 10 Standard test methods for determining average grain size. West Conshohocken, 2010. http://dx.doi.org/10.1520/E0112-10
4 ASSOCIAÇÃO BRASILEIRA DE NORMAS TÉCNICAS. NBR 6673: Produtos planos de aço: determinação das propriedades mecânicas a tração: método de ensaio. Rio de Janeiro, 1981.
5 KEELER, S. P. Determination of the forming limits in automotive stamping. Sheet Metal Industries, v. 42, n. 461, p. 683-91, Sept. 1965.
6 GOODWIN, G. M. Application of the strain analysis to sheet metal forming in the press shop. In: SAE AUTOMOTIVE ENGINEERING CONGRESS, 1968, Detroit, USA. [S.n.t.]. SAE paper 680093.
7 LUIZ, V. D.; CAMPOS, H. B.; MELO, T. M. F. Curva limite de estampagem à fratura (CLEF) versus curva limite de estampagem à estricção (CLEE). In: CONGRESSO ANUAL DA ABM, 62, 2007, Vitória, ES. São Paulo: ABM, 2007. p. 44-51.
8 MARCINIAK, Z.; DUNCAN, J. L.; HU, S. J. Mechanics of sheet metal forming. Reino Unido: Butterworth-Heinemann, 2002.
9 KEELER, S. P.; BRAZIER; W. G. Relationship between laboratory material characterization and press shop formability. In: MICROALLOYING 75: INTERNATIONAL SYMPOSIUM ON HIGH STRENGTH LOW ALLOY STEELS. 1975, Washington, D.C. Proceedings… Metals Park; ASM, 1977. p. 517-28.
10 ASAME. Reference Manual Version 4.12, Janeiro, 2008.
11 PEPELNJAK, T.; BARISIC, B. Computer-assisted engineering determination of the formability limit for thin sheet metals by a modified Marciniak method. The Journal of Strain Analysis for Engineering Design, v. 44, n. 6, p. 459-72, Ago. 2009.
12 MARCINIAK, Z.; KUCZYNSKI, K.; POKORA, T. Influence of the plastic properties of the material on the forming limit diagram for sheet metal tension. International Journal of Mechanical Sciences, v. 15, n. 10, p. 789-805, Oct. 1973. http://dx.doi.org/10.1016/0020-7403(73)90068-4
13 INTERNATIONAL ORGANIZATION FOR STANDARDIZATION. ISO 12004-2: Metallic materials-sheet and strip-determination of forming limit curves – part 2: determination of forming limit curves in laboratory. Geneva, 2007.
14 HOGSTROM, P.; RINGSBERG, J. W.; JOHNSON, E. An experimental and numerical study of the effects of length scale and strain state on the necking and fracture behaviours in sheet metals. International Journal of Impact Engineering, v. 36, n. 10-11, p. 1194-203, Oct.-Nov. 2009. http://dx.doi.org/10.1016/j.ijimpeng.2009.05.005
2 ASTM INTERNATIONAL. ASTM E45: 10e1 Standard test methods for determining the inclusion content of steel. West Conshohocken, 2010. http://dx.doi.org/10.1520/E0045-10E01
3 ASTM INTERNATIONAL. ASTM E112: 10 Standard test methods for determining average grain size. West Conshohocken, 2010. http://dx.doi.org/10.1520/E0112-10
4 ASSOCIAÇÃO BRASILEIRA DE NORMAS TÉCNICAS. NBR 6673: Produtos planos de aço: determinação das propriedades mecânicas a tração: método de ensaio. Rio de Janeiro, 1981.
5 KEELER, S. P. Determination of the forming limits in automotive stamping. Sheet Metal Industries, v. 42, n. 461, p. 683-91, Sept. 1965.
6 GOODWIN, G. M. Application of the strain analysis to sheet metal forming in the press shop. In: SAE AUTOMOTIVE ENGINEERING CONGRESS, 1968, Detroit, USA. [S.n.t.]. SAE paper 680093.
7 LUIZ, V. D.; CAMPOS, H. B.; MELO, T. M. F. Curva limite de estampagem à fratura (CLEF) versus curva limite de estampagem à estricção (CLEE). In: CONGRESSO ANUAL DA ABM, 62, 2007, Vitória, ES. São Paulo: ABM, 2007. p. 44-51.
8 MARCINIAK, Z.; DUNCAN, J. L.; HU, S. J. Mechanics of sheet metal forming. Reino Unido: Butterworth-Heinemann, 2002.
9 KEELER, S. P.; BRAZIER; W. G. Relationship between laboratory material characterization and press shop formability. In: MICROALLOYING 75: INTERNATIONAL SYMPOSIUM ON HIGH STRENGTH LOW ALLOY STEELS. 1975, Washington, D.C. Proceedings… Metals Park; ASM, 1977. p. 517-28.
10 ASAME. Reference Manual Version 4.12, Janeiro, 2008.
11 PEPELNJAK, T.; BARISIC, B. Computer-assisted engineering determination of the formability limit for thin sheet metals by a modified Marciniak method. The Journal of Strain Analysis for Engineering Design, v. 44, n. 6, p. 459-72, Ago. 2009.
12 MARCINIAK, Z.; KUCZYNSKI, K.; POKORA, T. Influence of the plastic properties of the material on the forming limit diagram for sheet metal tension. International Journal of Mechanical Sciences, v. 15, n. 10, p. 789-805, Oct. 1973. http://dx.doi.org/10.1016/0020-7403(73)90068-4
13 INTERNATIONAL ORGANIZATION FOR STANDARDIZATION. ISO 12004-2: Metallic materials-sheet and strip-determination of forming limit curves – part 2: determination of forming limit curves in laboratory. Geneva, 2007.
14 HOGSTROM, P.; RINGSBERG, J. W.; JOHNSON, E. An experimental and numerical study of the effects of length scale and strain state on the necking and fracture behaviours in sheet metals. International Journal of Impact Engineering, v. 36, n. 10-11, p. 1194-203, Oct.-Nov. 2009. http://dx.doi.org/10.1016/j.ijimpeng.2009.05.005
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