What is ADI

What is ADI (Austempered Ductile Iron)?


ADI is a cast iron material in which the carbon appears as nodules and the structure matrix consists of ausferrite. This ausferrite is a fine-grained mixture of ferrite and stabilised austenite which is a guarantee for the high hardness and ductility of ADI.


In ADI the chemical composition is laid down according to the relevant wall thickness of the material. In general it is aimed to achieve the following analysis:


C [%] Si [%] Cu [%] Ni [%] Mo [%]
3,5 – 3,7 1,9 – 2,3 0,6 – 1,0 0,6 – 2,5 0,15 – 0,3


With this composition, and depending on the form which the metallic matrix has, the material has an expected tensile strength of Rm = 800 to 1400 N/mm².


ADI is an alloyed form of spheroidal cast iron, in combination with a special form of heat treatment.



ADI und seine historische Entwicklung


… ein Werkstoff setzt sich durch!


1930 initial experimets with heat-treated cast iron

1937 documentation of the non-ferrous structire in grey cast iron (GJL)

1948 Millis: discovery and patenting of spheroidal cast iron (GJS)

1952 first sources of ADI

1960 General motors starts ADI gear programme




Erste industrielle ADI-Anwendungen:


1970 Crankshafts for the compressor in refrigerating equipment

1977 ring gears and pinions incar rear axle gears

1979 differential gearbox housings for all-wheel-drive light trucks

1980 crankshaft for Ford L4 engine

1984 toothed steering gear for commercial vehicle diesel engines

1990 truck spring hangers, stub axles and wheel hubs

1995 Fixing arm for Ford Mustang spring system

2002 wheel housing for VW Phaeton

1980 Start of systematic research into ADI

1990 Standardisation to ASTM in the USA

1997 Standardisation to EN- 1564 in Europe




ADI die Entwicklung bei HUBO:


1987  First encounter with the material ADI at the Finnish meehanite foundry, Höyfors

1990 First manufacture of ADI cast parts to test out the material

1997 Setting up of a quality assurance system with subsequent certification

1998 Start of series production after creation of DIN standard

2003 Production of aprox. 1,000 t ADI cast components which were sold exclusively at the subsidiary company, ADI Treatments Ltd in the UK.

2004 ADI Treatmeant Ltd sells 8,000 t of ADI components on the European market!

2005 increase in capacity at ADI Traetment through the installation of a third furnace to approx. 12,000 t per annum. 12000 J/.

2007 Hulvershorn builds a second foundry in Bocholt ( Germany)