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1

Performance of circular stainless‑carbon steel tube confned concrete stubs under axial compression

Gao Shan, Guo Lanhui, Zhang Sumei

Archives of Civil and Mechanical Engineering

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2022

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Vol. 22, no. 3

art. no. e104

EN

To increase the usage cost-efectiveness of stainless steel in structural members, a bimetallic tube composed of an external thin-walled stainless steel tube and an internal relatively thick-walled carbon steel tube is proposed. Fifteen stub specimens including nine stainless-carbon steel tube confned concrete (SCTCC) stubs and six concrete-flled stainless-carbon steel tubes (CFSCT) were tested and analyzed in detail. The results show that both SCTCC stubs and CFSCT stubs exhibit good mechanical performance and shear failure modes. The axial strength of SCTCC stubs is higher than that of CFSCT stubs. Regarding SCTCC stubs, the exterior stainless-steel tube would yield before the interior carbon-steel one. The parametric analysis shows that the rising in the thickness ratio of stainless steel tube would decrease the axial capacity of SCTCC model, but also cause the decrease in the axial resistance of the model beyond the peak to become more subtle. The predicting method regarding the capacity of SCTCC stub under axial compression is proposed based on the current design standard and test results.

2

Performance of circular bimetallic tube confined concrete slender columns under eccentric compression

Gao Shan, Guo Lanhui

Archives of Civil and Mechanical Engineering

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2021

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Vol. 21, no. 2

13--39

EN

This paper aims to investigate the performance of thin-walled circular stainless steel-carbon steel bimetallic tube confined concrete slender columns under eccentric compression. 14 slender columns including bimetallic tube confined concrete (BTCC) with and without rebar, and concrete-filled bimetallic tube (CFBT) were tested. A parametric analysis is conducted based on the validated finite-element model. The results show that the two steel tube layers worked well together and the thin-walled BTCC specimens behaved in a ductile manner. Under the same parameters, the decrease of the diameter–thickness ratio of bimetallic tube improves the bearing capacity and rigidity of the BTCC slender column, but reduces its ductility in the descending stage. The confinement effect of bimetallic tube on the concrete in BTCC columns is stronger than that in CFBT columns. When the yield strength of stainless steel and carbon steel is similar, the stainless steel–total steel ratio has little effect on the capacity of the column. Provided meeting the requirements of corrosion resistance, relatively thinner stainless steel tube is preferred to reduce the cost. The comparison between the simulation and the calculation results shows that the current design method can predict the bearing capacity of the BTCC slender column with large diameter–thickness ratio.

3

Analysis of Manufacturing Bimetallic Tubes by the Cold Drawing Process

Halaczek D.

Archives of Metallurgy and Materials

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2016

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Vol. 61, iss. 1

241--248

EN

Drawing processes apply to obtain the bimetallic tubes from the different metals and alloys, combined in the solid state, which significantly affects the specificity of this process. The manufacturing of bimetallic tubes by drawing process depends on many factors which include: preparation of the surface of materials joined in the solid state, the geometric parameters of the working tool, technological parameters of the drawing process (drawing speed, type of lubricant, the use of back pull etc.). Generally, the cold drawing process of producing the bimetallic tubes refers to metals which have high ductility (copper, aluminum, etc.). The tube sinking (tube drawing without a mandrel) of bimetallic tubes together with joining them at the interface of the two metal in the solid-state is applied for tubes of the diameter range between 6 to 20 mm and based on of the reducing the diameter of the tube. However, a slight increase of wall thickness ca. 0.05 ÷ 0.10 mm can appear, which is not dangerous phenomenon in case of producing the bimetallic tubes by joining in the solid-state. The aim of the research was to investigate the technology of tubes drawing process from non-ferrous metal, drawing process of bimetallic tubes and the production of bimetallic tubes in layers composition: cooper Cu-ETP - brass CuZn37 and CuZn37 brass - copper Cu-ETP in the tube sinking process. The research program included: production of bimetallic tubes with a different composition (Cu- ETP-CuZn37 and CuZn37-Cu-ETP) and a different percentage of the cross-section components; analysis of changes of tube wall thickness and the layer composition of the bimetallic tube, based on measurements on the workshop microscope; analysis of the material flow in the process of the bimetallic tubes production based on the measurements results of a profilograph CP-200.

4

Rury bimetalowe o własnościach antydrobnoustrojowych

Sobota J., Głuchowski W., Rdzawski Z., Marszowski K.

Rudy i Metale Nieżelazne Recykling

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2014

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R. 59, nr 1

16--22

PL

W artykule zaprezentowano najistotniejsze elementy technologiczne i techniczne związane ze sposobami wytwarzania rur kompozytowych zawierających miedź. Przedstawiono wyniki badań mikrostruktury rur bimetalowych z rdzeniem stalowym oraz ze stopu aluminium, w których warstwę wierzchnią stanowiły miedź lub mosiądz CuZn37 o wysokich własnościach antykorozyjnych i antybakteryjnych. Określono przyczepność powłoki do podłoża w próbie ściskania. Przeprowadzone badania potwierdziły możliwość wytworzenia rur bimetalowych bez wad. Stała strefa styku pomiędzy rurami na całym obwodzie cechowała się dobrym przyleganiem bez występowania jakichkolwiek nieciągłości. Mikrostruktura badanych rur była drobnoziarnista, typowa dla procesu ciągnienia. Warstwa zewnętrzna cechowała się dużą elastycznością i plastycznością, szczelnie opinając rurę wewnętrzną nawet, gdy rura ta traciła stateczność i pękała podczas próby ściskania. Wskazuje to na możliwość wytwarzania z nich wyrobów o skomplikowanych kształtach uzyskiwanych przez gięcie na zimno.

EN

The paper presents the most important technological and technical elements relating to preparation processes of the composite tubes containing copper. The microstructure of bimetallic tubes with steel or aluminium alloy core, while the surface layer was copper or brass CuZn37 (with high anti-corrosion and anti-bacterial properties) has been presented. Coating adhesion to the substrate in a compression test has been presented. The study confirmed the production possibility of bimetallic tubes without defects. The contact zone between the layers was characterized by good adhesion without any discontinuity. The microstructure was typical for the drawing process. The outer layer was characterized by high flexibility and plasticity that hugs the inner tube tightly even when it was losing stability and bursting during compression tests. This indicates the possibility of the preparation of these products with complicated shapes obtained by cold deformation.