Technical guidance on rebar sizes, yield strength grades, and the difference between ASTM A615 Deformed Bars and TMT bars.
Q: What are the most common rebar sizes?
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The most common rebar sizes in residential and commercial construction are #3 (9mm), #4 (12mm), #5 (16mm), and #6 (20mm). Heavy industrial structures, bridges, and high-rise columns typically utilize #8 (25mm), #10 (32mm), and #12 (40mm) bars.
Q: What does "Grade" mean in rebar?
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Rebar Grade defines the yield strength, ultimate tensile strength, chemical composition, and percentage elongation. Grade 40 represents a minimum yield strength of 40,000 PSI (280 MPa), while Grade 60 represents 60,000 PSI (420 MPa).
Q: What is a Metric Tonne (T)?
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A Metric Tonne (T) is equivalent to 1,000 kilograms or 2,204.6 pounds. Steel procurement and site deliveries across Pakistan are universally calculated in Metric Tonnes.
Q: What are TMT bars?
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TMT stands for "Thermo Mechanical Treatment". In this process, steel bars are intensively cooled immediately after rolling. The sudden temperature drop hardens the outer surface while keeping the inner core hot, which tempers as it cools down naturally.
Q: Why do some TMT bars fail ASTM A615 Chemical & Tensile Standards?
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Many TMT bars in the market are rolled from low-cost, unrefined scrap metal. This process focuses strictly on boosting surface yield strength but fails to maintain the required 30,000 PSI gap between yield strength and ultimate tensile strength specified in ASTM A615. Over-tempering can also cause bar failure during 180-degree bend testing.
Q: Why choose AL-QAWI STEEL ASTM Deformed Bars?
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AL-QAWI STEEL manufactures rebars under strict metallurgical quality control with 100% verification of chemical purity, physical elongation, and tensile ratio, ensuring structural safety for high-rise buildings and long-span bridges across Pakistan.
