Austempered Ductile Iron


Austempered Ductile Iron is also referred to as ADI. This material has been developed to offer enhanced strength and wear resistant properties. Impact resistance of Ductile Iron is retained. This material also offers enhanced fatigue properties.

Post casting austempering is an isothermal heat treatment applied to SG Iron materials. The chemical analysis of the SG Iron has to be controlled very carefully to ensure that the maximum mechanical properties resulting from the post casting solution treatment are achieved.

Additions of copper, nickel and molybdenum are made to improve hardenability. Austempered Ductile Iron (ADI) is being used for demanding applications and is replacing carbon steel castings and forged components due to the following benefits:


When compared to carbon steel castings and steel forgings and fabrications ADI – Austempered Ductile iron has a lower manufacturing cost.


ADI has a lower casting temperature than steel and this allows for a superior surface finish and the ability to cast complex shapes incorporating changes of section.

Tensile Strength

1600 N/mm2 can be achieved with certain grades of Austempered Ductile Iron.

Weight Saving

 ADI has a lower density than steel.  Casting designs incorporate near net shape offering significant weight savings over steel castings.

Improved Noise Damping

The presence of graphite in the Austempered Ductile Iron improves noise damping.

Superior Wear and Abrasion Resistance

The wear characteristics of ADI improve in service. Hardening occurs during normal operational use. Therefore ADI is a perfect choice high abrasion application.


The ability to cast to near net shape reduces the machining costs of ADI castings when compared to steel products.


Material designation; symbol and (number)
EN-GJS-800-8(EN-JS1100) EN-GJS-1000-5(EN-JS1110) EN-GJS-1200-2(EN-JS1120) EN-GJS-1400-1 (EN-JS1130)
Characteristic Unit Minimum values for properties 1) (normative)
Tensile Strength Rm N/mm2 800 1000 1200 1400
0.2% proof stress R po.2 N/mm2 500 700 850 110
Elongation A % 8 5 2 1
Impact resistance valuesCharpy notched, at (23±5) °C J 10 2) mean value of 3 tests
9 3) individual value
Minimum values for properties 1) (informative)
Compression strength N/mm2 1300 1600 1900 2200
0.2% proof stress N/mm2 620 770 1040 1220
Shear strength N/mm2 720 900 1080 1260
Torsional strength N/mm2 720 900 1080 1260
0.2% proof stress N/mm2 350 490 590 770
Impact resistance valuesCharpy notched, at (23±5) °C J 100 80 60 30
Fracture tougness K Mpa-m 1/2 62 58 54 50
Fatigue limit (Wöhler)(rotating bending) unnotched(dia. 10.6mm) N/mm2 375 425 450 375
Fatigue limit (Wöhler)(rotating bending) notched 4)(dia. 10.6mm) N/mm2 225 260 280 275
Typical Values
Brinell hardness HN 260 to 320 300 to 360 340 to 440 380 to 480
Modulus of elasticity E kN/mm2 170 168 167 165
Poisson’s ratio v 0.27 0.27 0.27 0.27
Shear modulus kN/mm2 65 64 63 62
Density p kg/dm3 7.1 7.1 7.1 7.1
Linear expansioncoefficient a mm/(m.K) 14.6 14.3 14 13.8
Thermal conductivity W/(m.K) 22.1 21.8 21.5 21.2


Note 1: The mimimum values can be obtained on wall thickness up to 50mm. For heavier sections agreement between purchaser and manufacturer is recommended.

Note 4: Notched after heat-treatment.