Austempering: heat treatment of ductile iron
Austempering: the key strength of Zanardi Fonderie for high-performance, light and sustainable ductile iron castings
Thanks to our austempering furnaces, we also perform heat treatments for third parties
Staff at Zanardi Fonderie performs heat treatments on cast parts in spheroidal graphite iron in a dedicated internal division equipped with hi-tech furnaces for the manufacture of austempered ductile irons ADI, ideal for the manufacture of lightweight, high-performing mechanical parts for use in on-road and off-road vehicles, industrial gear reducers, earth moving machinery and agricultural machinery.
Thanks to the austempering heat treatment, it is possible to give the ductile iron mechanical properties comparable or superior to those of quenched and tempered steel, maintaining the typical lightness of ductile iron and its natural capacity to adapt to the manufacture of complex moulds.


The Zanardi Austempering brand for outsourced heat treatment
The Austempering plant in the Zanardi Fonderie facility
We can treat castings up to a maximum of 1,000 kg, from very small batches to automotive volumes.

How the austempering heat treatment occurs
After loading the treatment baskets and a pre-heating stage, they are inserted into one of our AFC Holcroft UBQA 36″ x 72″ x 36” furnaces.
For each austempering heat treatment, our staff defines the times, treatment temperature, number of pieces per basket and their positioning based on the thickness of the casting, chemical analysis and desired ADI grade.
Thanks to this procedure, it is possible to achieve and guarantee a constant, high-quality result.




Stages of the austempering heat treatment
How the austempered ductile iron is obtained
The temperatures and cycle times are therefore adapted and regulated based on the desired ADI grade, the thickness of the part being treated and alloying element content.
The result and product of the austempering heat treatment
ADI – which in its various grades maintains the lightness typical of ductile iron and lends to the easy moulding of complex design shapes – is a material with superior mechanical properties with respect to those of classic spheroidal graphite iron, and comparable or superior to those of quenched and tempered steel.