Thermo-Mechanically Treated Bars Made from Recycled Steel in Uganda

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Author(s) Senfuka C. | Kirabira J.B. | Byaruhanga J.K.
Pages 183-188
Volume 3
Issue 2
Date February, 2013
Keywords Tramp elements; reinforcement bars; hardenability; ductility; recycled steel.

Abstract

Thermo-mechanically treated (TMT) reinforcement bars constitute an important turning point in the construction industry due to their capacity to envelope high strength, high ductility and low cost simultaneously. The properties of any material depend heavily on their chemical content. Steel in Uganda being mainly of the recycled origin has an abundance of residual elements. The purpose of this study was to establish the effect of these elements on the quality of the locally made TMT recycled steel bars. Particular interest has been paid to features influencing hardenability since it is the underlying factor in the mechanical peculiarities of TMT bars. Micro-hardness plots, tensile tests and spectro-analysis have been done on thirty randomly selected samples from local steel manufactures in order to relate the mechanical properties of the bars to their tramp element content. Unequal axial distribution of properties, asymmetrical radial distribution of hardness, low and inconsistent ring to core hardness ratio have been sighted as direct results of the recycled origin of the bars. Ladle refinement and the use of sponge/HB iron have been recommended as viable solutions in view of the existing national ore resources.

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