Fe 500D vs Fe 550D TMT bars: what is the difference?

Fe 500D and Fe 550D are two grades of thermo-mechanically treated (TMT) reinforcement bar covered by the Indian standard IS 1786. The number is the minimum yield strength in megapascals (MPa), and the letter D means higher ductility.

The main differences

Figures are the minimums in IS 1786. Check the current edition of the standard and confirm them against the mill test certificate.

What it means on site

Fe 550D is stronger, so a design can sometimes use less steel for the same load. Fe 500D stretches more before it breaks, which is useful in structures that must tolerate movement. The correct grade is the one your structural engineer specifies, not the cheaper one.

Check which standard your market specifies

Projects in East Africa often specify a British or East African standard rather than the Indian one. Ask your engineer whether Fe 500D is accepted as equivalent, and ask us to confirm with the mill.

What to ask for before you buy

• A recent mill test certificate showing chemical composition, yield, tensile strength and elongation.
• Bar sizes and standard length, and the bundle weight.
• Tags on each bundle showing the grade and the heat number.
• The pre-export certificate your country requires, where it applies.

See our TMT bars page for sizes and weights, or request a quote with your grade and quantity.