The
research focused on “Investigation of the yield strength of locally
manufactured steel reinforcement bars”. The steel samples were obtained from
two sources, sample B1 to B4 (B1-B4) Universal Steel Company (USC), Ikeja,
Lagos state and sample A1 to A4 (A1-A4) Open market (OPM), Timber market
Ahiaeke Umuahia, Abia State. The study assessed the mechanical and physical
properties of these steels produced in Nigeria and also compared there
conformance with the following code of designs, International Standard
Organization (ISO 6935-2:2007), British standard code (BS4449:1997), American
Standard for Testing Materials (ASTM A706) and Nigeria Steel Testing (Nst
465-Mn: 1994). From the tensile strength results of the samples tested, sample
A1-A4 of OPM failed to conform to BS4449:1997 minimum yield strength of 460 MPa,
ASTM A706 of 410 MPa, ISO 6935-2:2007 of 450 MPa and Nst 465-Mn of 420 MPa
while Only sample B3 (16 mm) diameter bar from USC conformed to the standards.
Sample B2 (12 mm) and B4 (20 mm) were within the satisfactory condition of
410-460 MPa while sample B1 (10 mm) of USC failed. The yield strength value for
10 mm, 12 mm, 16 mm and 20 mm of USC samples are 380, 449, 482 and 438 MPa
while 205, 372, 304 and 349 MPa are the yield strength values for OPM steel
samples, respectively. All the steel samples satisfy the BS4449:1997 minimum
percentage elongation of 14%. This shows that the steels are very ductile. In
conclusion, it is necessary to re-examine the strength of steels obtained from
Nigeria before using them.
