Engineering Tools
Reference data for specifying and sourcing fasteners correctly — the numbers a procurement or design engineer actually needs.
Steel composition by grade
Indicative chemical composition ranges (ISO 898-1 for carbon/alloy steel, ISO 3506-1 for stainless) — a mill certificate is the authoritative source for any specific batch.
| Grade | Carbon (C%) | Manganese (Mn%) | Phosphorus max | Sulphur max | Notes |
|---|---|---|---|---|---|
| 4.6 / 4.8 | ≤0.55 | — | 0.05 | 0.06 | Low/medium carbon steel, not heat treated |
| 8.8 | 0.15–0.40 | 0.30–1.20 | 0.025 | 0.025 | Medium carbon steel, quenched & tempered |
| 10.9 | 0.20–0.55 | alloyed (Mn/B) | 0.025 | 0.025 | Alloy steel, quenched & tempered |
| 12.9 | alloy steel | Cr-Mo typical | 0.025 | 0.025 | High-strength alloy steel |
| A2 (304) | ≤0.08 | ≤2.0 | 0.045 | 0.03 | Cr 17–19%, Ni 8–10.5% |
| A4 (316) | ≤0.08 | ≤2.0 | 0.045 | 0.03 | Cr 16–18%, Ni 10–14%, Mo 2–3% |