Guides
Fe 500 vs Fe 550D vs Fe 600
The number is the minimum yield in N/mm2, so Fe 600 stands highest of the three, and the D on Fe 550D buys stretch: IS 1786 asks 14.5 percent elongation of Fe 550D, 12 percent of Fe 500 and 10 percent of Fe 600.
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- 1 table of figures
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All three sit inside one standard, IS 1786, and all three are on the grade list Jay Shree Infra keeps at its Saharsa godown, along with Fe 500D and Fe 550. On the rack are SAIL TMT and five more names, and not every grade is in every brand on a given day, so say the grade with the diameter when you ring. Every figure below is read from the standard as it stands after its four amendments, which for the grade table means Amendment No. 3 of March 2017. The diameters themselves, and what each one weighs, are on the TMT bar (sariya) page.
Settle one thing before the table. The grade does not change what a bar weighs. Nominal mass in IS 1786 follows the diameter and nothing else, so 12 mm in Fe 600 and 12 mm in Fe 500 are the same 0.888 kg per metre on paper, and a tonne holds the same count of rods either way. What the grade changes is what the bar has to survive in a testing machine. The weight side is worked out in full in the sariya weight chart.
The numbers
What IS 1786 asks of each grade
Minimum yield, the tensile floor, and the two elongation figures, for the five grades we stock.
Scroll the table sideways to see every column
| Grade | YieldN/mm2, minimum | Tensile strengthN/mm2, minimum | Elongationpercent, minimum | Elongation at maximum forcepercent, minimum |
|---|---|---|---|---|
| Fe 500 | 500 | 545 | 12.0 | no figure set |
| Fe 500D | 500 | 565 | 16.0 | 5.0 |
| Fe 550 | 550 | 585 | 10.0 | no figure set |
| Fe 550D | 550 | 600 | 14.5 | 5.0 |
| Fe 600 | 600 | 660 | 10.0 | no figure set |
Table 3 of IS 1786:2008 as substituted by Amendment No. 3 of March 2017, which is the version in force. The 2008 printing reads differently and quoting it today would be quoting a table that has been replaced twice. The tensile column is an absolute floor: beside it the standard also fixes a minimum ratio of tensile strength to the bar's own measured yield, so a bar that yields well above its grade minimum has to pull further before it passes. The last column is tested where the purchaser asks for it, and the three plain grades carry no figure in that row at all.
Where Fe 550D parts from Fe 550
Both have to reach 550 N/mm2 before they yield. After that they separate. Fe 550 has to stretch 10 percent before it breaks and Fe 550D 14.5 percent, and Fe 550D has to hold 5 percent at maximum force, a row Fe 550 answers with nothing. Amendment No. 3 also rewrote the note that explains the letters: D and S mark categories with the same minimum yield and, in the standard's own words, "enhanced and additional requirements".
There is no Fe 600D and there never has been. Clause 1.1 lists eleven grades, and they are Fe 415, Fe 415D, Fe 415S, Fe 500, Fe 500D, Fe 500S, Fe 550, Fe 550D, Fe 600, Fe 650 and Fe 700. The D grades in that list stop at Fe 550D. If something is offered to you as 600D, read what is rolled on the bar before you take the word for it.
The bend test bends the higher grade less
The three separate again in the testing machine. IS 1786 bends a sample round a mandrel, and the mandrel gets fatter as the grade number climbs. Up to and including 20 mm it is 4 times the bar diameter for Fe 500 and for Fe 550D, and 5 times for Fe 600. Above 20 mm the same three read 5, 5 and 6.
The rebend test, where a sample is bent one way and then bent back, opens the gap wider. Up to 10 mm the mandrel is 5 times the diameter for Fe 500, 6 for Fe 550D and 7 for Fe 600. Over 10 mm it is 7, 7 and 9. Those are figures about a laboratory test and nobody should read them as a promise about a ring bent cold on a site. What they show is which way the standard's own allowance runs as the grade number goes up.
Ladle analysis
The chemistry each grade has to stay inside
Clause 4.2 sets the ladle analysis and Amendment No. 3 substituted that clause too. Fe 500 is allowed up to 0.30 percent carbon, 0.055 sulphur, 0.055 phosphorus, and 0.105 for sulphur and phosphorus together. Fe 550D is held to 0.25 carbon, 0.040 sulphur, 0.040 phosphorus and 0.075 together. Fe 600 is the odd one of the three: it keeps the 0.30 carbon of the plain grades and takes the tighter 0.040, 0.040 and 0.075 of the D grades.
SAIL prints the same D grade maxima beside its own SeQR figures in its brochure, 0.25 carbon and 0.040 each way on sulphur and phosphorus. Every one of those is a ceiling the cast has to stay under, not a description of any bar in front of you. What a particular cast actually ran is on the test certificate against the cast number, which is a document to ask for.
At this counter
The drawing picks the grade, we say what is standing
The grade for a house is not a counter decision. IS 1786 fixes what a bar has to be and says nothing whatever about a slab, a column or a footing, so the grade comes off the structural drawing.
What we can tell you is what is standing here. Those five are the IS 1786 grades we stock on the sariya rack, and the same rack carries two more names the standard does not: NXT 600, which is a brand name, and project grade, which is a buying category. Not every grade is in every brand on a given day. What is standing this morning is a phone call, not a fixed list.
Sources
The amendment these figures are read from
The standard's own record of which version is current, the amendment that substituted the grade table and the chemistry clause, and one maker publishing its figures against the same table.
Questions
Grade ke sawal
Ghar ki dhalai me kaun sa Fe grade chalega?
Whatever the structural drawing says. IS 1786 fixes what each grade has to survive in a test and lays down no rule for a slab, so the design decides and the shop cannot. Bring the number off the drawing to the call on +91 6202 967 218 and we will tell you what is standing in it that morning.
Fe 600 sabse strong hai to wahi le lein?
Highest yield of the three, and the least stretch. Fe 600 has to reach 600 N/mm2 where Fe 500 reaches 500, and it has to stretch 10 percent where Fe 550D stretches 14.5. The standard bends it round a fatter mandrel too, 5 times the diameter up to 20 mm against 4 for the other two. Which of those matters on your job is on the drawing.
Fe 600D naam ka koi sariya hota hai?
No. Clause 1.1 of IS 1786 lists eleven grades and Fe 600D is nowhere among them; the D grades stop at Fe 550D. Fe 550S does not exist either. If a bundle is offered to you under one of those names, read the marks rolled into the bar and the tag on the bundle, and ring us with what they say.
Grade badalne se sariya ka weight badal jayega?
No. Nominal mass in IS 1786 goes by diameter alone, so 12 mm is 0.888 kg per metre in Fe 500 and in Fe 600 both, and a tonne holds the same rods either way. What moves the figure on a weighbridge is the mill tolerance, which the weight chart guide works out size by size.
Before you order
Four questions for the call
What grade does the structural drawing say?
The one question we cannot answer. It sits beside the diameter on the drawing, and reading it out takes a few seconds.
Which grades are standing in that diameter today?
Grade and diameter travel together on this rack. Say both and we will tell you what is in, and in which name.
What is rolled on the bar, and what does the bundle tag say?
Licensed bar carries the maker and the grade rolled into the steel, and the tag carries the cast or lot number, the grade and the size. Ring us if those two disagree with what you ordered.
Does the specification ask for a test certificate?
Say so with the grade and the approved make when you ring. We will tell you what that consignment can travel with before anything is loaded.
Contact
Read the tag, then ring us
The grade is on the drawing, rolled into the bar and printed on the bundle tag, and all three should say one thing. Read us what they say and we will tell you what is standing in that grade this morning and today's rate on it.
Shop hours: All 7 days, 9:30 AM to 6:00 PM