“Wear behavior of CADI operating under different tribosystems”. ISIJ International

S. LAINO; J. SIKORA; R. DOMMARCO

ISIJ INTERNATIONAL

The Iron and Steel Institute of Japan

Lugar: Tokyo; Año: 2009

0915-1559

A new type of Austempered Ductile Iron (ADI) containing free carbides in the microstructure, called Carbidic ADI (CADI), is purposely designed for applications requiring high levels of abrasion resistance but still conserving impact toughness. CADI is currently under development and during the last years research activities have been carried out aiming to obtain different variants of this material, studying its microstructure versus mechanical properties relationship. Previous results obtained by the authors have shown that CADI has an interesting combination of mechanical properties, particularly high abrasion resistance with impact toughness higher to other materials of similar wear resistance. Nevertheless, the wear resistance is strongly dependent on the tribosystem. This is clearly noticed when a specific abrasive wear mechanism is acting. In previous investigations the authors have used the low stress abrasion condition imposed by the ASTM G 65 standard in laboratory tests. The main objective for the present study was to evaluate the wear resistance of CADI under different abrasion conditions by means of field trials. Besides additional laboratory tests under the ASTM G 65 standard, two CADI prototype parts were evaluated, screw segments for animal food extruders, considered to have abrasion of low stress type (similar to that imposed in the lab), and wheel loader bucket edges, where abrasion is considered of high stress type. The results show that CADI behaves satisfactorily for the low stress abrasion condition, and that the performance is not good for the high stress condition. To justify the differences in wear behavior, scratch tests were performed in order to evaluate the interaction between the abrasive particles and the microstructure.