ductile iron grades ASTM A536 vs EN-GJS
Who this helps: Buyers and Design Engineers selecting ductile (nodular/SG) iron for housings, hubs, brackets, manifolds and pressure-tight parts.
What you’ll get: a clean A536 ↔ EN-GJS cross-reference, typical property windows, and a practical grade selection path you can put on drawings.
Prepared by YB Metal Solution. Share your drawing—YB Metal will return a material recommendation, process notes and a quote.
Author: YB Metal Solution Engineering Team (hereafter YB Metal)
Table of contents
- How A536 and EN-GJS map (and where they don’t)
- Cross-reference table: ASTM A536 ↔ EN-GJS
- Typical properties & what shifts them
- Selection guide: pick the grade by design driver
- Notes for drawings: CT, Ra, stock, testing
- Process & cost considerations
- What YB Metal delivers
- FAQs
How A536 and EN-GJS map (and where they don’t)
Choose shell molding over green/resin sand when you need:
- ASTM A536 grade notation is UTS–Yield–Elongation in ksi/% (e.g., 65-45-12).
- EN 1563 (EN-GJS) uses UTS–Elongation in MPa/% (e.g., EN-GJS-450-10).
- Both specify minimums on test pieces; actual casting properties vary with section size, matrix (ferrite/pearlite), and process. Use the table below as a practical mapping, not a legal equivalence.
Cross-reference table: ASTM A536 ↔ EN-GJS
| ASTM A536 Grade (UTS–YS–El%) | Approx. MPa (UTS) | Typical EN-GJS Pairing (UTS–El%) | Where it’s used |
|---|---|---|---|
| 60-40-18 | ~415 | EN-GJS-400-18 | Ferritic DI: maximum ductility, low-temp toughness, pressure parts, shock loading. |
| 65-45-12 | ~450 | EN-GJS-450-10 | General-purpose DI for housings, brackets, hubs—balance of ductility and strength. |
| 80-55-06 | ~550 | EN-GJS-500-7 | Pearlitic/ferritic DI: higher strength, good fatigue; common for hubs/flanges. |
| 100-70-03 | ~690 | EN-GJS-700-2 | High-strength DI: loaded arms, carriers; watch elongation & section size. |
| 120-90-02 | ~830 | EN-GJS-800-2 / 900-2 | Very high strength; consider section-size limits, machining & impact trade-offs. |
Synonyms: ductile iron = nodular iron / SG iron / spheroidal-graphite iron; EN uses GJS (spheroidal).
Typical properties & what shifts them
Indicative windows for design screening at room temperature. Your part’s data depends on wall (mm/in), cooling, matrix and heat treatment.
| Property | Ferritic DI (e.g., 60-40-18 / EN-GJS-400-18) | Balanced DI (65-45-12 / EN-GJS-450-10) | Higher-strength DI (80-55-06 / 100-70-03 ≈ EN-GJS-500-7 / 700-2) |
|---|---|---|---|
| UTS (MPa) | ~400–460 | ~440–520 | ~520–750 |
| Yield (MPa) | ~250–320 | ~300–380 | ~370–520 |
| Elongation (%) | ~14–22 | ~8–14 | ~2–8 |
| Hardness (HBW) | ~140–190 | ~170–220 | ~200–270 |
| Fatigue (R=-1, MPa) | ~160–200 | ~180–230 | ~200–280 |
| Low-temp toughness | Best (down to −40 °C) | Good | Check vs spec; can drop with pearlite |
What moves the numbers
- Matrix: more pearlite → ↑UTS/HB/fatigue, but ↓elongation & low-temp toughness.
- Section size: thin walls (≤10 mm / 0.4 in) cool faster → stronger; heavy sections trend lower.
- Heat treatment: normalize for stronger/pearlitic matrices; austemper for ADI grades (see ADI guide).
- Magnesium treatment & inoculation quality: graphite nodule count/shape drives ductility and toughness.
Selection guide: pick the grade by design driver
| Design driver | Recommended grades | Why |
|---|---|---|
| Max ductility / leak-tight / −40 °C service | 60-40-18 / EN-GJS-400-18 or 65-45-12 / EN-GJS-450-10 (ferrite-rich) | Ferritic matrix absorbs impact and resists brittle behavior at low temp. |
| Balanced cost–strength for housings/hubs | 65-45-12 / EN-GJS-450-10 | Common workhorse; easy to machine; solid fatigue margin. |
| Fatigue-critical hubs/flanges/arms | 80-55-06 / EN-GJS-500-7 | Higher UTS/HB improves fatigue; still machinable. |
| High static load / stiffness with limited ductility | 100-70-03 / EN-GJS-700-2 | High strength—watch section size and impact. |
| Weight reduction vs ductile iron | ADI (e.g., 900-6 / 1050-6) | Strength-to-weight boost; confirm NVH & machining. See ADI page. |
Helpful internal reads:
- Ductile vs Gray Iron (design & cost trade-offs)
- ADI (Austempered DI) process & grades
- Wall thickness rules
Notes for drawings: CT, Ra, stock, testing
- Material call-out (example):
- “EN-GJS-450-10 (ASTM A536 65-45-12 acceptable). Ferrite ≥ 60% on sealing faces.”
- As-cast tolerance: specify ISO 8062-3 CT by size band (e.g., CT8–CT10 typical for mid-size housings).
- Surface finish: as-cast Ra 6.3–12.5 µm (resin/green); sealing faces after machining Ra 1.6–3.2 µm.
- Machining stock: faces/ODs +1.5–3.0 mm (0.06–0.12 in); bores by diameter band.
- Testing on first articles: spectrometer per heat, hardness trend, tensile on coupons, microstructure at SC zones; leak/NDT if pressure-tight.
Process & cost considerations
- Green sand is cost-leading for mainstream housings/hubs; see capability/cost
- Resin sand gives cleaner surfaces and core freedom on complex parts; compare
- Shell molding helps thin walls and CT tightening; see thin-wall rules → (your shell-molding page).
- Tooling vs piece price: for high volumes or tighter CT, higher tooling may pay back; see break-even guide → (your tooling vs piece price page).
What YBmetal delivers
YB Metal Solution pours EN-GJS-400–700 (A536 60-40-18 → 100-70-03) with:
- Processes: green/resin sand; shell cores for thin features.
- Metallurgy & QA: OES chemistry, nodule count/shape, tensile & hardness, microstructure.
- Inspection: CMM & 3D scan on datum scheme; PPAP/FAI up to Level 3.
- Finish: machining and coatings (epoxy/powder) with DFT logs.
Want a grade and process recommendation? Upload your drawing—YB Metal will return the best-fit grade, CT band and machining stock plan.
FAQs
CTA — specify with proof, not guesses
Lock the right grade the first time. Upload your drawing and YBmetal will propose the material, CT band and machining plan that hit your targets.