IS 226 : 1975Structural Steel (Standard Quality)

IS 226:1975 has been withdrawn. It was the long-time standard for structural steel of standard quality (Fe 410-S) — the workhorse mild steel for fabrication of beams, columns, plates, angles, and channels in India. It was officially superseded by IS 2062:2011 (which covers Fe 410, Fe 440, Fe 490, Fe 540, Fe 590 grades).

Why this page still gets searched: many older drawings (especially before 2011), legacy contracts, repair/strengthening of existing structures, mill test certificates from old stock, and academic references all cite IS 226. Engineers checking compatibility with old structures or interpreting old documentation arrive here.

Use IS 2062:2011 for new design and fabrication. Use IS 226 only as a reference when: - Reverse-engineering an old drawing that names IS 226 - Reviewing strengthening of pre-2011 structures (calibrating the as-built steel grade) - Reading historical mill certificates issued before 2011

The Fe 410-S of IS 226 is essentially the Fe 410 grade in IS 2062:2011 with minor chemistry refinements — for most as-built assessment work, treat them as equivalent.

Designation: Fe 410-S (S = standard quality)

Mechanical properties: - Tensile strength: 410-530 MPa (yield-to-ultimate range, not minimum yield) - Yield stress: ≥ 250 MPa for sections ≤ 20 mm thick; ≥ 240 MPa for 20-40 mm; ≥ 230 MPa for > 40 mm - Elongation (gauge length 5.65 √A): ≥ 23 % for plates and sections - Bend test: 180° around a mandrel of 2t (t = thickness) without cracking

Chemical composition (max % by mass): - Carbon: 0.23 % (≤ 20 mm thick); 0.22 % (> 20 mm); for welding-quality up to 0.20 % - Sulphur: 0.055 % - Phosphorus: 0.055 % - Manganese: not directly capped (typically 0.5-1.5 %)

Product forms covered: - Plates, sheets, strip - Sections: I-beams (ISMB, ISLB, ISWB), channels (ISMC, ISLC), angles (ISA), tees - Round, square, hexagonal bars (structural quality, not reinforcement — that's IS 432 or IS 1786)

When a legacy specification or drawing calls for IS 226 Fe 410-S, the contemporary equivalent in IS 2062:2011 is:

| Old (IS 226) | New (IS 2062:2011) | Notes | |---|---|---| | Fe 410-S | E 250 (Fe 410 W) | Default replacement; matches yield 250 MPa | | Fe 410-O (older Indian designation) | E 250 (Fe 410 W) | Same as above | | Higher tensile classes | E 300 / E 350 / E 410 / E 450 | Newer higher-strength grades unavailable in IS 226 |

Key chemistry change in IS 2062:2011: - Tighter caps on carbon and CE (carbon equivalent) for weldability — `CE = C + Mn/6 + (Cr+Mo+V)/5 + (Ni+Cu)/15` - For E 250 Quality A, B, BR, C: weldability progressively better - Most fabrication work today calls for E 250 Quality BR (improved weldability and notch toughness — V-notch Charpy ≥ 27 J at 0 °C)

Design code linkage: IS 800:2007 explicitly references IS 2062 grades in its design tables. IS 226 is not mentioned in IS 800:2007 — design must use IS 2062 grades.

• IS 2062:2011 — the current standard for hot-rolled medium and high-tensile structural steel.
• IS 800:2007 — design code for structural steel; specifies grades from IS 2062.
• IS 1786:2008 — high-strength deformed steel bars for RCC reinforcement (different code family — this is for rebar, not structural steel).
• IS 808:1989 — dimensions for rolled steel sections (ISMB, ISLB, ISWB, ISMC, ISA, etc.) — still current; both IS 226 and IS 2062 steel is rolled to IS 808 sections.
• IS 432 Part 1:1982 — mild steel and medium tensile bars for concrete reinforcement (rebar code, plain bars).
• IS 4923:2017 — hollow sections (CHS, RHS, SHS) for steel structures.
• IS 7215 — fabrication tolerances on steelwork.
• IS 9595 — welding consumables / procedures for IS 2062 steels.

For design of new structures: ignore IS 226 entirely. Use IS 2062:2011 E 250 Quality BR for routine fabrication; E 350 / E 410 for higher-strength members.

For repair / strengthening of existing structures: 1. Identify the as-built steel grade from drawings (often 'Fe 410' or 'Fe 410-S' under IS 226). 2. Treat as IS 2062 E 250 for capacity calculations — this is conservative for almost all real cases. 3. Verify by mill test certificate if available; if not, take a coupon sample and test per IS 1608 Part 1:2022 (tensile test). 4. New steel introduced for strengthening is IS 2062:2011 — match the grade to the existing for compatibility, or design for the lower of the two. 5. Welding old steel: assume it's not weldability-quality (IS 226 had loose carbon limits). Use low-hydrogen electrodes, preheat ≥ 100 °C, and consider mechanical fastening as a safer alternative.

For tender / contract documentation: if a legacy tender still references IS 226, replace with `Steel grade equivalent to IS 2062:2011 E 250 Quality BR or higher; supplier shall furnish IS 2062 mill test certificate.`