دراسة الخصائص الميكانيكية وتكلفة بعض أنواع حديد التسليح الليبي والمستورد

Abstract

This research aims to study and evaluate the mechanical and chemical properties of five types of reinforcement steel bars commonly used in Libyan markets: Sidi Al-Sayeh, Misurata, Zliten, Algerian (imported), and Turkish (imported). A series of standard tests were conducted, including Rockwell hardness testing (HRB scale), tensile testing according to ASTM E8, bending testing, chemical analysis using Optical Emission Spectroscopy (OES), and microscopic examination to study the microstructure.

The hardness test results revealed that Algerian steel recorded the highest value (72.66 HRB), followed by Misurata steel (72 HRB), while Sidi Al-Sayeh steel recorded the lowest value (56 HRB), indicating higher ductility. In the tensile test, Misurata steel exhibited the highest tensile strength of 893.57 N/mm² with the highest yield stress (750 N/mm²), while Sidi Al-Sayeh steel showed the lowest strength (578.04 N/mm²) but the highest elongation percentage (17%), indicating good flexibility. All five samples successfully passed the bending test without any cracks or fractures, confirming their suitability for use in concrete structures. Chemical analysis revealed that all samples contained acceptable proportions of essential elements according to ASTM A615 standards. The higher carbon content in Misurata and Algerian steel contributed to increased hardness and tensile strength, while lower carbon content in Sidi Al-Sayeh and Turkish steel resulted in higher ductility. Microscopic examination showed the presence of ferrite and pearlite phases in varying proportions, where smaller grain sizes are associated with increased tensile strength, while larger grains enhance ductility.

From an economic perspective, Misurata steel showed the highest market prices in Libya during 2023-2025, reflecting its superior quality and higher production costs, while Sidi Al-Sayeh steel was the most affordable. The study recommends selecting reinforcement steel based on engineering project requirements, balancing strength, ductility, and cost, and emphasizing the necessity of periodic testing to ensure compliance with standard specifications.