Determination of Mechanical Properties of Locally Fabricated Steel Billets from Ajaokuta Steel Company Products

This study determines the mechanical properties of steel billets and downstream products fabricated at the Ajaokuta Steel Company Complex, Kogi State, North Central Nigeria. Ajaokuta remains Nigeria's most significant integrated steel plant, and the mechanical characterisation of its products relative to international standards is essential for assessing the competitiveness and reliability of locally produced structural steel. Billet samples and corresponding rolled bar products are obtained from different heats at the Ajaokuta complex and subjected to tensile testing, Charpy impact testing, Brinell hardness measurement, and bend testing in accordance with BS 4449 and ASTM A615 standards. Microstructural examination using optical microscopy and SEM is performed to assess grain structure, inclusion content, and surface quality. Chemical composition is verified by optical emission spectroscopy. Findings reveal that the majority of tested samples meet minimum yield strength and tensile strength requirements, with a coefficient of variation below 8 percent across heats. However, impact energy values at low temperatures fall below BS 4449 minimum thresholds for a significant proportion of specimens, suggesting inadequate manganese content control. Surface quality variations are documented, linked to inconsistent rolling mill maintenance. The study provides benchmark mechanical data for Ajaokuta products and recommends tighter melt chemistry controls and rolling mill rehabilitation to achieve consistent compliance with international structural steel standards. Keywords: steel billets, mechanical properties, Ajaokuta Steel Company, structural steel, Kogi State.