Patent for MADI

Intermet Corporation’s Domestic Ferrous Group announced recently that the company has been awarded a US patent for Machinable Austempered Ductile Iron (MADI).

The new ferrous-metal material is said to provide improved strength compared to traditional ductile iron plus improved machinability and improved fatigue performance compared to traditional austempered ductile iron.

‘Today’s vehicle and industrial equipment manufacturers demand components that are both durable and lightweight,’ said Dr. Alan Druschitz, Technical Manager at Intermet’s Archer Creek Foundry in Lynchburg, Virginia, and co-developer of MADI. ‘Because the design strength of MADI is 50 to 100 percent higher than current as-cast ductile irons, significantly lighter weight components can now be designed.

‘MADI will lead to the increased use of low-cost ductile-iron castings since for the first time improved mechanical properties and improved machinability both have been achieved.’

The patent (US Patent No.7,070,666, issued July 4, 2006) covers key elements of the new material and the method of manufacture, including a proprietary heat-treatment process.

MADI was developed by Intermet in 2001 at the company’s Research Foundry in Lynchburg for casting automotive structural and powertrain components such as control arms, steering knuckles and crankshafts. It has enabled Intermet to manufacture ferrous-metal components for safety-critical applications at lower cost and with much improved performance characteristics when compared with competing steel forgings, welded steel assemblies or aluminium castings.

Intermet currently has MADI vehicle control-arm and steering-knuckle programs in production at its Archer Creek Foundry and has developed MADI engine crankshafts for an NHRA (National Hot Rod Association) professional drag racer.