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ArcelorMittal r/t Ratio (Bend Radius)

⚙️ Mechanical · Brand-specific minimum bend radius / thickness ratio for high-strength steel plate

🧮 Calculate∑ Formula✅ Verification📚 Sources

Steel GradeThickness t (mm)

Bending force calculation

Bend length b (mm)

Tensile strength Rm / UTS (MPa)

FamilySu verilmiş (Q&T)

r/t ratio2

Minimum inside bend radius40 mm

Minimum die opening (W)160 mm

💡 Values apply to 90° bending. For legacy (non-banded) grades, only data for the direction PERPENDICULAR to rolling is published. For the Mars® series, both parallel and perpendicular data are available via the selector above. For MC (thermomechanical) grades, lower-strength classes (650–700) are only certified in the transverse direction. For standard structural steels like S235–S355, no brand-specific ArcelorMittal value is published, so they are not included here — refer to the general DIN 6935 standard for those grades.

Required bending force F— (requires a valid bend radius/thickness/UTS; W must exceed R + thickness)

💡 F = b·t²·Rm / (W − R − ep) — where b: bend length, t=ep: plate thickness, Rm: tensile strength (UTS), W: die width (taken from the minimum die opening above), R: mandrel radius (taken from the minimum bend radius above). Source: ArcelorMittal/Industeel Mars® user guide, p.31. For non-Mars® grades, the UTS value is not auto-filled and must be entered manually.

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r_{min} = \left(\frac{r}{t}\right) \times t

When cold-bending high-strength steel plate, if the strain (elongation) on the outer surface of the material exceeds a certain limit, cracking occurs. The minimum inside bend radius (r) required to stay under that limit is expressed as a multiple of the plate thickness (t) — this ratio (r/t) grows as the material’s strength increases, since higher-strength steels typically have lower total elongation capacity.

The values in this tool are taken from the bending tables officially published by ArcelorMittal/Industeel for the Amstrong Ultra (quenched, high-strength) and thermomechanical (MC) grade families — valid for 90° bending, perpendicular to the rolling direction. No brand-specific ArcelorMittal value is published for standard structural steels (such as S235–S355); refer to the general DIN 6935 standard for those grades.

Practical note: the minimum die opening is similarly given as a multiple of thickness — directly usable for die selection in a press-brake bending operation.

⚠️ Note: These values are taken from ArcelorMittal/Industeel's publicly available technical brochure and are for general reference. For critical/safety-sensitive applications, rely on the manufacturer's current, product-specific technical data sheet and quality certificates.

✅ Verified

This tool's calculation logic has been checked against a hand-computed numerical verification test. Test source: src/lib/calc/arcelor-rt.test.ts.

[24] ArcelorMittal / Industeel. Amstrong Ultra — Fold Brochure (PR-BR-AMU-EN). ArcelorMittal Europe – Flat Products, 2019. ↗

ArcelorMittal r/t Ratio (Bend Radius) — EngineersLab calc card

Formula: r_min = (r/t) × t

Sources: [24] Amstrong Ultra — Fold Brochure (PR-BR-AMU-EN)

Tool version: 1.0.0 · Date:

Source URL: https://engineerslab.com.tr/en/araclar/arcelor-rt

Results are for educational and preliminary-sizing purposes; final engineering design decisions must reference the relevant standards and a licensed engineer's approval.