Forming process using austempered ductile iron (ADI) in an automotive Pitman arm

This paper describes the machining and forming process of a Pitman arm, proposed to be used in the automotive industry, from austempered ductile cast iron ( ADI) as an alternative to the commonly used material, AISI 1045 steel. Samples were austenitized at 900 degrees C for 180 min and subsequently austempered in a salt bath over a range of temperatures, from 340 to 360 degrees C, for 60 min, to obtain favorable mechanical properties. The results of metallographic testing show that the pieces formed with ADI have an average nodularity of 92.5%, and the average nodule count is 159 nodules/mm(2). Mechanical tests results of strength, elongation, hardness, and impact energy are comparable to that of ASTM standard A897-15 grade 1. A finite element simulation and an experimental analysis were performed to determine the forming force and the material strength. The deformation limits for ADI were identified. These limits and the simulation results show that ADI is an attractive alternative high-strength material for the Pitman arm application.