The steel every structure on this site is made from. What the grade number means, what the letter after it changes, and why the letter is the part buyers get wrong.
IS 2062 is the specification for hot rolled medium and high tensile structural steel. The grade designation is direct: E250 means a minimum yield stress of 250 MPa, E350 means 350 MPa, and so on.
The part that causes trouble is the letter after the number. A, BR, B0 and C are not strength grades — the strength is identical. They differ only in the Charpy V-notch impact test, and therefore in how the steel behaves when it is cold, shocked or dynamically loaded.
| Grade | Min. yield stress | Min. tensile strength | Min. elongation |
|---|---|---|---|
| E250 | 250 MPa | 410 MPa | 23% |
| E350 | 350 MPa | 490 MPa | 22% |
| E410 | 410 MPa | 540 MPa | 20% |
Yield stress is quoted for the lower thickness range. Yield falls as section thickness increases — always check the allowable against the actual thickness rather than the headline grade figure. Higher grades (E450 and above) exist in the standard for specialised work.
Same strength, different toughness. This is where a specification is won or lost.
| Sub-grade | Charpy V-notch impact requirement | Where it belongs |
|---|---|---|
| A | No impact test required | Non-critical fabrication and general-purpose work |
| BR | 27 J minimum at room temperature | Most general construction in moderate Indian climates |
| B0 | 27 J minimum at 0 °C | Cold climates and dynamically loaded structures |
| C | 27 J minimum at −20 °C or lower | Critical low-temperature and high-consequence work |
A drawing that says only “IS 2062 E250” has not specified toughness. For a transmission tower in a Himalayan corridor or a structure carrying dynamic load, that omission is the difference between the right steel and the cheap one.
Answered from our own line, not from the standard's cover page.
A minimum yield stress of 250 MPa. The number in the grade designation is the yield figure directly. E250 also carries a minimum tensile strength of 410 MPa and 23% minimum elongation.
Strength is identical. They differ only in the Charpy V-notch impact test: Grade A requires none, BR requires 27 J at room temperature. For dynamically loaded or cold-service structures the sub-grade is the specification that matters, not the yield number.
Yes — it falls as thickness increases. The headline grade figure applies to the lower thickness range. Always work the allowable stress from the actual section thickness in the drawing.
Yes. We run a Bruker Q2 ION optical emission spectrometer on site, imported from Germany and commissioned in June 2026, reading steel, zinc, aluminium and copper. We also run a universal testing machine and a Rockwell hardness tester, and an in-house tool room for jigs and fixtures.
It is set by the design, not by us — IS 802 governs the tower and the designer specifies the grade and sub-grade. We fabricate to the drawing and certify what we used, with mill test certificates supplied against every consignment.
Tell us the standard, the coating requirement and the component, and we will confirm in writing what we can hold and how we will certify it. Galvanizing is on our own floor, so the answer comes from us and not from a sub-contractor.
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