What is A.D.I (Austempered Ductile Iron)?
Austempering is an isothermal heat treatment process, which significantly improves both the strength and wear resistance of ductile iron whilst retaining the impact resistance and ductility for which the material is noted. A.D.I is a proven cost-effective alternative to cast and forged steel and offers the following advantages:
The microstructure of A.D.I
Properties:
Strength
Tensile strength of up to 1600 N/mm2.
Machining
Nearness to nett shape reduces machining costs.
Tooling
Tooling is less expensive with improved lead time when compared to forging dies.
Wear Resistance
A.D.I. actively resists wear; during any form of work the immediate surface hardens.
Weight Saving
10% lighter than steel. Higher strength allows smaller sections than conventional S.G castings, whilst retaining performance criteria.
High fatigue resistance
At the tip of any crack, the material changes into an extremely hard material arresting crack propagation.
Piece Price
As a conversion from steel castings, forgings and fabrications, A.D.I. can very often offer worthwhile cost savings.
Metallurgy
The heat treatment process has the effect of altering the metallic matrix to fine needles of ferrite in a solution of iron and carbon also known as ausferrite.
Grade | Yield Strength Rp0.2 MPa Min. | Tensile Strength Rm MPa Min. | Elongation % Min. | Unnotched Impact, J Min. | Hardness BHN* |
850/550/10 | 550 | 850 | 10 | 100 | 269-321 |
1050/700/7 | 700 | 1050 | 7 | 80 | 302-363 |
1200/850/4 | 850 | 1200 | 4 | 60 | 341-444 |
1400/1100/1 | 1100 | 1400 | 1 | 35 | 388-477 |
1600/1300 | 1300 | 1600 | – | – | 444-555 |