Indian Standard for Atmospheric Corrosion-Resistant Structural Steel
IS 11587 is an Indian Standard that specifies weathering resistant (WR) steels designed to offer improved resistance to atmospheric corrosion compared to conventional carbon structural steels. It is primarily used in infrastructure, industrial structures, and general outdoor fabrication within India.
IS 11587 WR Steel serves as a civil and industrial counterpart to railway-specific grades like IRSM 41, providing corrosion resistance where Indian Standards (IS) compliance is required.
IS 11587:1986 specifies structural steel plates with enhanced atmospheric corrosion resistance. This grade is especially suitable for structural components exposed to open environments and aggressive weathering conditions, delivering long-term performance without the need for frequent repainting.
IS 11587 was developed to define structural steels with:
• Improved resistance to atmospheric corrosion
• Adequate strength for load-bearing applications
• Suitability for outdoor exposure under Indian climatic conditions
The standard specifies:
• Chemical composition limits
• Mechanical property requirements
• Test methods and acceptance criteria
IS 11587 is commonly referenced in PSU, EPC, and government projects where IS codes are mandated.
IS 11587 is typically selected when:
• Indian Standards (IS) compliance is mandatory
• Structures are exposed to outdoor environments
• Reduced corrosion compared to IS 2062 is required
• Railway-specific standards (IRSM) are not applicable
It provides a balanced solution between availability, corrosion resistance, and structural performance.
| Element | Typical Range % |
|---|---|
| Carbon (C) | ≤ 0.16 |
| Copper (Cu) | 0.20 – 0.55 |
| Chromium (Cr) | 0.30 – 1.00 |
| Nickel (Ni) | ≤ 0.65 |
| Phosphorus (P) | ≤ 0.15 |
| Manganese (Mn) | ≤ 1.50 |
Exact limits vary by grade and thickness. Always verify MTC as per IS 11587.
| Property | Typical Value |
|---|---|
| Yield Strength | 340 – 450 MPa (grade-dependent) |
| Tensile Strength | 470 – 630 MPa |
| Elongation | ≥ 17% |
WR Fe 480 is selected primarily for its higher yield strength, enabling reduced steel tonnage in structural members.
IS 11587 WR Steel is often compared with other Indian corrosion-resistant grades:
| Grade | Primary Use |
|---|---|
| IS 11587 WR | Civil & industrial structures |
| WR Fe 480 | Higher strength WR applications |
| IRSM 41-97 | Indian Railways |
👉 Selection should be based on governing authority and design requirement, not only corrosion resistance.
Sharoff Steel Suppliers can supply IS 11587 WR Steel in:
• Plates
• Sheets
• Structural sections (subject to rolling availability)
• Cut-to-size material
Infrastructure
• Bridges and flyovers (non-railway)
• Outdoor support structures
Industrial
• Equipment frames
• Ducts and chimneys
• Structural supports
Power & EPC
• Exposed plant structures
• Utility frameworks
IS 11587 WR Steel is designed for general atmospheric exposure under Indian conditions. However, it may not be the preferred option when:
• Railway specifications apply
→ In such cases, IRSM 41-97 is typically mandated.
• Higher yield strength is required
→ WR Fe 480 or EN/ASTM weathering grades may be more suitable.
• Project specifications mandate international standards
→ EN 10025-5, ASTM A588, or JIS SPA-H may be required instead.
Grade selection should always be based on the governing authority, design code, and load requirement, not corrosion resistance alone.
For IS 11587 supplies, the following are typically required:
• Mill Test Certificate (MTC) as per IS 11587
• Grade and chemistry declaration
• Heat number traceability
• Strong understanding of Indian Standards and PSU requirements
• Reliable sourcing with full traceability
• Guidance on choosing between IS 11587, IRSM 41, and WR Fe grades
• Support to avoid mis-specification in EPC projects
We help customers select the right Indian WR grade, not just “weathering steel”.
| Requirement | Recommended Grade |
|---|---|
| Railway application | IRSM 41-97 |
| Higher strength WR | WR Fe 480 |
| IS-code civil works | IS 11587 |
| Export / EPC | EN / ASTM / JIS |
When should IS 11587 be preferred over IRSM 41?
IS 11587 is preferred for non-railway civil and industrial projects where IS compliance is required and railway specifications do not apply.
Is IS 11587 suitable for outdoor Indian conditions?
Yes. It is designed for atmospheric exposure typical of Indian environments, provided proper design and drainage are ensured.
IS 11587 WR Steel is India’s standard solution for corrosion-resistant structural applications outside the railway domain. When specified correctly, it offers improved durability, reasonable strength, and IS-code compliance.
At Sharoff Steel Suppliers, IS 11587 is supplied with Indian-standards clarity and project-specific guidance.