23MnB4
1.5535Cold-heading boron steel — optimized for cold forming of high-strength fasteners. Boron gives hardenability equivalent to much more expensive Cr-Mo alloys. Supplied spheroidized for cold heading, then quenched+tempered after forming. Property class 10.9 bolts are commonly made from this grade. Used for high-strength bolts (M8-M24), screws, studs, and threaded fasteners for automotive and construction.
International equivalents
| Flag | Standard | Country | Grade | Number | Match |
|---|---|---|---|---|---|
| 🇪🇺 | EN | Europe | 23MnB4 / 1.5535 | 1.5535 | 100% |
Sources: EN 10263-4
Chemical composition comparison (wt%)
Side-by-side: 23MnB4 (EN 10263-4) vs 23MnB4 / 1.5535 (EN) (EN 10263-4)
| Element | 23MnB4 (EN 10263-4) | 23MnB4 / 1.5535 (EN) | Overlap |
|---|---|---|---|
| C | — | 0.2–0.27% | — |
| Si | — | 0–0.4% | — |
Mechanical properties
Compatibility verdict
23MnB4 and 23MnB4 / 1.5535: 100% composition match
Related materials
42CrMo4
1.7225High-strength quenched and tempered chromium-molybdenum steel. Widely used for shafts, gears, crankshafts, connecting rods, and high-strength bolts. Excellent hardenability and good fatigue resistance.
34CrNiMo6
1.6582High-strength quenched and tempered Cr-Ni-Mo steel. Excellent hardenability and toughness, suitable for large cross-sections. Used for heavy-duty shafts, gears, turbine parts, and aerospace components.
16MnCr5
1.7131Low-carbon case-hardening steel with manganese and chromium. Excellent for carburizing to produce a hard, wear-resistant surface with a tough core. Standard choice for gears, camshafts, piston pins, and transmission components.
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