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