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MIL-DTL Armor Steels

⚙️ Mechanical · Thickness-dependent hardness (Brinell) range lookup for US military armor steel specifications

🧮 Calculate∑ Formula✅ Verification📚 Sources

Specification / ClassThickness (mm)

Full nameRolled Homogeneous Armor (RHA), Class 1 — general purpose

Hardness range (Brinell)340–390 HB

Chemical composition (max.)C max 0.27% (≤50.8mm) / 0.29% (50.8–101.6mm) / 0.31% (>101.6mm) — varies with thickness; other alloying elements are separately limited in the spec.

The most common vehicle armor class. Carbon content increases with thickness: max 0.27% for ≤50mm, 0.29% for 50–100mm, 0.31% for >100mm (MIL-DTL-12560K).

💡 Values are taken from the official US DoD specification texts (everyspec.com / DLA ASSIST-QuickSearch), not manufacturer catalog values. Tensile/yield strength and density are not defined in these specifications — only hardness and ballistic performance requirements are set; strength figures found online are manufacturer typical values, not official requirements.

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This tool relies on table/conversion logic rather than a single closed-form formula.

The US Department of Defense’s armor steel specifications (MIL-DTL series) define the material not with a single strength value, but as a thickness-dependent hardness band plus a ballistic performance requirement. This tool shows the hardness band read from the official texts of the three main specifications (RHA, HHA, UHHA) directly for the selected thickness.

Three families:

MIL-DTL-12560 (RHA — Rolled Homogeneous Armor): the most common vehicle armor. Class 1 is general-purpose, Class 2 prioritizes shock/mine resistance (tougher, lower hardness), Class 4 offers enhanced penetration resistance (hardest).
MIL-DTL-46100 (HHA — High-Hardness Armor): a single, fixed hardness band (477–534 HB), independent of thickness.
MIL-DTL-32332 (UHHA — Ultra-High-Hardness Armor): defines only a lower bound (min. 570 HBW) — there is no upper limit. Mainly used for applique/add-on armor.

Important: none of these specifications set an official tensile/yield strength or density requirement — only hardness and ballistic performance (V50) are defined. Strength figures found online are manufacturer certificate/catalog values, not official specification requirements.

⚠️ Disclaimer: The data in this tool is compiled from the US Department of Defense's publicly available, unclassified, unlimited-distribution specification texts; it contains no classified or export-controlled technical data. This information is for educational and general reference purposes only — for actual armor design, manufacturing, or procurement, consult the relevant country's defense industry regulations, export control laws, and authorized agencies. EngineersLab and its founder accept no liability for any legal consequences arising from the use of this information.

✅ Verified

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

[26] US Department of Defense. MIL-DTL-12560K}: Armor Plate, Steel, Wrought, Homogeneous. Defense Logistics Agency, 2013. ↗
[27] US Department of Defense. MIL-DTL-46100E}: Armor Plate, Steel, Wrought, High-Hardness. Defense Logistics Agency, 2008. (DLA ASSIST kayıtlarına göre güncel revizyon F'dir; bu kaynakta Rev E metni esas alınmıştır) ↗
[28] US Department of Defense. MIL-DTL-32332A}: Armor Plate, Steel, Wrought, Ultra-High-Hardness. Defense Logistics Agency, 2018. ↗

MIL-DTL Armor Steels — EngineersLab calc card

Sources: [26] MIL-DTL-12560K}: Armor Plate, Steel, Wrought, Homogeneous; [27] MIL-DTL-46100E}: Armor Plate, Steel, Wrought, High-Hardness; [28] MIL-DTL-32332A}: Armor Plate, Steel, Wrought, Ultra-High-Hardness

Tool version: 1.0.0 · Date:

Source URL: https://engineerslab.com.tr/en/araclar/mil-dtl-zirh

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