Austempered Ductile Iron (ADI) Grade 1: High-Strength Lightweight Cast Material
ASTM A897 · Published: 2026-06-03 · Updated: July 2026
Austempered Ductile Iron (ADI) is produced by austempering ductile iron — a specialized isothermal heat treatment that creates an ausferrite microstructure (acicular ferrite + carbon-stabilized austenite) with a unique combination of high...
Austempered Ductile Iron (ADI) is produced by austempering ductile iron — a specialized isothermal heat treatment that creates an ausferrite microstructure (acicular ferrite + carbon-stabilized austenite) with a unique combination of high strength, good ductility (8%), and 10% lower density than steel. It is replacing forged steel in truck suspension components, gears, and crankshafts.
Quick Facts
| Category | Cast Iron |
| Standard | ASTM A897 |
| Density | 7.10 g/cm³ |
| Yield Strength | 758 MPa (110 ksi) |
| Tensile Strength | 965 MPa (140 ksi) |
Global Equivalents & Cross-Reference
Related Materials
🧮 Material Weight Calculator
Calculate the weight based on this material's density: 7.10 g/cm³
Frequently Asked Questions
What makes ADI different from standard ductile iron?
Standard ductile iron's matrix is ferrite, pearlite, or tempered martensite — all well-understood phases. ADI's ausferrite microstructure is unique to austempered cast irons: the acicular ferrite provides strength while the stabilized austenite provides ductility and work-hardening capability. The result is a material with twice the strength of standard ductile iron at the same ductility level.
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