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| Effect of Thermomechanical Treatment on T/Y Ratio in Recycled Plain Carbon Steel Reinforcement Bars |
Christopher SENFUKA, Paul Kizito MUBIRU,
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Abstract:
- Ensuring that the bars for reinforcement purposes behave as intended means maintaining a limit on the yield stress so that that the TS/YS ratio is kept at 1.25. While this is easy to control in core hardened steel bars, the composite nature of thermo mechanically treated (TMT) bars with a pearlite/ferrite core surrounded by a tempered bainite/martensite outer ring through phase transformation strengthening renders them less predictable. In this research the influence of the chemical composition of the TMT against its heat treatment is compared to that in annealed and core hardened bars of the same samples. Parts of TMT bars were fully annealed while others were fully quenched and had their composition determined in each case while they ultimate stresses and yield stress were recorded. A plot of the ratio T/Y against their calculated carbon equivalent was made. It was shown that the T/Y ratio reduces with growing carbon equivalent and that the plot for the T/Y ratio for the TMT bars fits between those for fully annealed and for the fully quenched group. Hence the reliability of the TMT bars in earthquake conditions will be less than that of fully annealed bars but higher than those that are fully martesized.
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