Indostar Fe 550D TMT Bar - 8 mm is a 8 mm diameter Thermo-Mechanically Treated (TMT) high-strength deformed steel rebar from Indostar, manufactured to IS 1786:2008 (High Strength Deformed Steel Bars and Wires for Concrete Reinforcement) in the special Fe 550D grade — combining a minimum yield strength of 550 MPa with an enhanced minimum elongation of 14.5%, significantly exceeding standard Fe 550. The 'D' designation certifies high strength with enhanced ductility (D-grade) for superior seismic performance and safe structural behaviour, making this 8 mm bar the ideal choice for stirrups, links, ties, distribution bars, and temperature reinforcement in slabs and beams where both high strength and bending ductility are critical. Each IS-marked bar in 12 m lengths is produced with controlled chemistry for superior weldability and consistent rib geometry for maximum concrete bond in all seismic zone construction.

• Fe 550D grade TMT rebar: minimum yield strength 550 MPa, tensile 600 MPa, elongation 14.5%
• UTS/YS ratio ≥ 1.08 — IS 1786:2008 D-grade requirement for ductile concrete reinforcement
• Bar diameter 8 mm in 12 m standard lengths — consistent cross-section and weight per IS 1786:2008 schedule
• Thermo-Mechanical Treatment process: hard martensitic surface ring + tough ductile ferrite-pearlite core
• IS-marked per IS 1786:2008 with full heat-wise batch mill test certification (MTC)
• Enhanced ductility designation 'D': 14.5% elongation far exceeds standard Fe 550 (10%) for seismic safety
• Controlled low carbon equivalent chemistry for excellent site weldability without preheating
• Uniform deformed rib pattern per IS 1786:2008 for superior mechanical bond and anchorage in concrete
• Low sulphur and phosphorus content for improved toughness, fatigue resistance, and durability
• Suitable for all IS seismic zones — meets IS 13920:2016 earthquake-resistant detailing requirements

• Earthquake-resistant (seismic) RCC frame construction in all IS seismic zones I–V
• High-rise building columns, shear walls, core walls, and transfer slab reinforcement
• Bridge decks, box girders, pier caps, and abutment reinforcement in major road/rail projects
• Heavy industrial structures: equipment foundations, reactor pedestals, and chimney stacks
• Piled foundations, pile caps, and raft foundation mats for heavy-load structures
• Nuclear power plant safety structures, containment domes, and shielding concrete
• Metro rail viaducts, station boxes, and underground tunnel lining reinforcement