TMT Bar Grades, Compared

Strength goes up, ductility comes down, and the D grades are how you get some of it back. Here is the whole table in one place.

Every grade in IS 1786:2008 side by side. Strength goes up as you go down the table; ductility goes down with it. The D grades buy back that ductility.
Grade	Yield (MPa)	UTS (MPa)	Elong. %	TS/YS	S+P max %	Positioning
Fe 415	415	485	14.5	1.10	0.110	Ductile, low-strength general purpose grade
Fe 415D	415	500	18.0	1.12	0.085	Extra-ductile variant of Fe 415
Fe 500	500	545	12.0	1.08	0.105	The default working grade of Indian construction
Fe 500D	500	565	16.0	1.10	0.075	Strength of Fe 500 with controlled ductility and tighter chemistry
Fe 500S	500 (max 625)	1.25 x actual yield	18.0	1.25	0.075	Purpose-built seismic grade with a capped upper yield
Fe 550	550	585	10.0	1.06	0.100	High-strength grade for steel-saving designs
Fe 550D	550	600	14.5	1.08	0.075	The premium structural grade — high strength without giving up ductility
Fe 600	600	660	10.0	1.06	0.075	Highest strength grade recognised in IS 1786
Fe 500 CRS	500	545	12.0	1.08	0.175	Corrosion resistant steel with controlled copper, chromium and phosphorus

Grade pages