ASTM A536 Grade 100-70-03: Quenched-and-Tempered High-Strength Ductile Iron
ASTM A536 · Published: 2026-06-03 · Updated: July 2026
ASTM A536 Grade 100-70-03 is the highest-strength standard ductile iron grade — achieving 689 MPa tensile through quenching and tempering to create a pearlitic/tempered martensite matrix. It is specified for high-load gears, crankshafts,...
ASTM A536 Grade 100-70-03 is the highest-strength standard ductile iron grade — achieving 689 MPa tensile through quenching and tempering to create a pearlitic/tempered martensite matrix. It is specified for high-load gears, crankshafts, connecting rods, and hydraulic cylinder components where forged steel is not cost-effective.
Quick Facts
| Category | Cast Iron |
| Standard | ASTM A536 |
| Density | 7.10 g/cm³ |
| Yield Strength | 483 MPa (70 ksi) |
| Tensile Strength | 689 MPa (100 ksi) |
Global Equivalents & Cross-Reference
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Frequently Asked Questions
Can 100-70-03 ductile iron replace forged steel?
In many applications, yes. Grade 100-70-03 has tensile strength comparable to AISI 1045 forged steel (655 MPa) at approximately 30-40% lower finished part cost due to near-net-shape casting eliminating extensive machining. However, ductile iron has lower fatigue strength than forged steel (~35% of tensile vs ~50% for steel), so forged steel is still required for the highest-fatigue applications.
References & International Standards
- ASTM International. Standard Specifications for Steel & Metal Alloys. astm.org
- International Organization for Standardization (ISO). Metallic Materials — Cross-Reference Database. iso.org
- American Iron and Steel Institute (AISI). Steel Grade Designations & Equivalents. steel.org
- European Committee for Standardization (CEN). EN Steel Standards & Numbering System. cencenelec.eu