Thermomechanical Processing and Constitutive Strength of Hot Rolled Mild Steel
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Date
2010-07
Authors
Sekunowo, I.O
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Abstract
This work examined thermo-mechanical and metallurgical parameters (temperature and cooling rate) that give rise to substantial improvement in the basic functional strength characteristics of high-yield reinforcing steels produced in a conventional mill. A new process tagged Temperature Tracking-Jet Water Spray (TT-JEWAS) was developed to achieve requisite in-process control of thermal variations on one hand and fast undercooling by spray quenching on the other. The alternative microstructure obtained, lower bainite instead of pearlite induced in the steel, gave rise to a significant improvement in the strength characteristics (Yield strength, 422-843MPa; Ultimate tensile strength, 704-1173MPa, Impact energy, 85-111J) and reliability of the steel. These compared favourably with both local and international standards (NIS 117:2004, BS 4449:1988 and ASTM A615: 1996). This result implies that substantial import substitution can be achieved in the high-yield reinforcing steel bar industry to give tremendous boost to the nation’s Gross Domestic Products (GDP). Bainitic Yield strength-band and Empirical model developed from the results of this work are extremely useful for in-process quality control and prediction of yield strength of hot rolled steel bars. This will lead to improvement in processing methods in the local steel industry.
Description
A Thesis Submitted to the School of Postgraduate Studies, University of Lagos
Keywords
Engineering , Steel Industry , Thermo-mechanical and metallurgical parameters , Thermal Variations , Research Subject Categories::TECHNOLOGY::Engineering mechanics
Citation
Sekunowo, I.O (2010). Thermomechanical Processing and Constitutive Strength of Hot Rolled Mild Steel. A Thesis Submitted to University of Lagos School of Postgraduate Studies Phd Thesis and Dissertation, 104pp.