Theoretical and practical aspects of the production of thin-walled tubes by the KOBO method

Bochniak, W.; Marszowski, Krzysztof; Korbel, A.

doi:10.1016/j.jmatprotec.2005.02.258

Cited by 47 publications

(33 citation statements)

References 21 publications

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“…[50] KOBO guarantees highly fragmented and homogeneous structure of products. [51,52] It consists of inducing cyclic changes of the deformation path in material being subjected to deformation as a result of the cyclic change of the straining scheme. Consequently, there is a permanent destabilization of the structure and the dominance of localized plastic flow in the intersecting shear bands.…”

Section: Kobo Methodsmentioning

confidence: 99%

Visco-Plastic Flow of Metal in Dynamic Conditions of Complex Strain Scheme

Korbel

Bochniak

Ostachowski

et al. 2011

Metall Mater Trans A

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The article applies to a piece of research inspired by the new technology of plastic metal forming called the KOBO method, which uses the mechanical and structural effects of cyclic changes of deformation path. Its commercial usage in the field of large plastic deformations, especially for the production of extruded elements made of hardly deformable metal alloys, naturally generated a question about the optimal conditions for carrying out the process and the criteria for their establishment, i.e., constitutive description. In this context, the work provides data on the force and energy consumption of aluminum and 7075 aluminum alloy extrusion processes, carried out using the KOBO method, and their dependence on the strain rate and temperature. The mechanism of deformation occurring during extrusion by the KOBO method was identified as visco-plastic flow. Characteristic parameters of the process, such as viscosity coefficiency, activation energy, activated volume, and the concentration of point defects generated during the process were evaluated.

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Section: Kobo Methodsmentioning

confidence: 99%

Visco-Plastic Flow of Metal in Dynamic Conditions of Complex Strain Scheme

Korbel

Bochniak

Ostachowski

et al. 2011

Metall Mater Trans A

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“…Materials produced by SPD have good mechanical and physical properties [5][6][7][8]. Age-hardening effect in connection with grains refinement to ultrafine scale are the main approaches to improve strength and ductility.…”

Section: Introductionmentioning

confidence: 99%

Influence of Solution and Aging Treatment Conditions on the Formation of Ultrafine-Grained Structure of CuFe2 Alloy Processed by Rolling with Cyclic Movement of Rolls

Urbańczyk-Gucwa

Radwański

Rodak

2016

Archives of Metallurgy and Materials

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The effect of second phase particles on grain refinement in CuFe2 alloy has been investigated by using rolling with the cyclic movement of rolls (RCMR) method. Two different population of second phase particles of Fe: coherent, about 10 nm in diameter and about 100 nm in size were obtained by applying aging treatment followed at 500°C for 2 h and at 700°C for 24 h respectively. In addition, solution treated samples were deformed by RCMR method at the same parameters. The microstructures of the CuFe2 alloy were analyzed using light microscope (LM), electron backscattered diffraction (EBSD) microscope technique and scanning transmission electron microscope (STEM). The presence of high-density of coherent Fe particles in the matrix inhibits recovery process and in the result obtained grain/subgrain boundaries have diffused character and are weakly visible. The largest particles which are not coherent with the matrix act as an effective barrier against the boundary motion.

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“…Relatively new and promising one is a KoBo method. Its grave advantage is imposing accumulated plastic deformation under only one cycle [18][19]. This paper considers comparison of microstructure and mechanical properties change in technical pure aluminum alloy AA1050 subjected to ECAP and KoBo processes.…”

Section: Introductionmentioning

confidence: 99%

Analysis of Microstructure and Mechanical Properties Changes in AA1050 Aluminum Subjected to ECAP and KoBo Processes / Analiza Zmian Mikrostruktury I Własności Mechanicznych Aluminium AA1050 Po Procesie ECAP I KoBo

Bogucki

Sulikowska

Bieda

et al. 2015

Archives of Metallurgy and Materials

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AnAlysIs of mIcrostructurE And mEchAnIcAl propErtIEs chAngEs In AA1050 AlumInum subjEctEd to EcAp And Kobo procEssEsAnAlizA zmiAn mikrostruktury i włAsności mechAnicznych Aluminium AA1050 po procesie ecAp I KoboAnalysis of the results of the microstructure and the mechanical properties change in AA1050 aluminum alloy of technical purity processed using ECAP (Equal Channel Angular Pressing) and KoBo deformation methods are presented in the paper.. ECAP process was performed according to Bc scheme in the range from 1 up to 10 passes. Changes of microstructure were analyzed using scanning electrone microscope equipped with electron backscattered diffraction (EBSD) system. Microstructure and fraction of high-angle grain boundaries in KoBo processed samples were similar to those observed in ECAP processed samples after four passes. The most significant microstructure refinement was observed in ECAP processed sample submitted to 10 passes. In ECAP method the systematic increase of mechanical properties was observed along with increase of deformation degree.

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Theoretical and practical aspects of the production of thin-walled tubes by the KOBO method

Cited by 47 publications

References 21 publications

Visco-Plastic Flow of Metal in Dynamic Conditions of Complex Strain Scheme

Visco-Plastic Flow of Metal in Dynamic Conditions of Complex Strain Scheme

Influence of Solution and Aging Treatment Conditions on the Formation of Ultrafine-Grained Structure of CuFe2 Alloy Processed by Rolling with Cyclic Movement of Rolls

Analysis of Microstructure and Mechanical Properties Changes in AA1050 Aluminum Subjected to ECAP and KoBo Processes / Analiza Zmian Mikrostruktury I Własności Mechanicznych Aluminium AA1050 Po Procesie ECAP I KoBo

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