Abrasion and Impact Properties of Partially Chilled Gray Iron

J.V. GIACCHI, R.A. MARTÍNEZ, M.R. MARTÍNEZ GAMBA AND R.C. DOMMARCO

WEAR

Elsevier Science S.A.

Lugar: New York NY, USA; Año: 2007 p. 282 - 291

0043-1648

ABSTRACT This paper reports the results of laboratory tests carried out to evaluate the abrasion wear resistance and impact properties of partially chilled gray iron (PCGI). Even though the impact property may not be an important characteristic for this type of material, the purpose of this characterization is to compare it with the one obtained for partially chilled ductile iron (PCDI). This allows to evaluate the influence of graphite morphology on the impact resistance of a chilled matrix and also, based on this knowledge, to choose for the lower cost variant when possible. The versatility of the casting process allows the use of chills (also referred as coolers) at specified locations in the mold, in order to increase the solidification rate and, in consequence, to promote the precipitation of carbides for an improved abrasion resistance. Two different heats, alloyed and unalloyed, were studied. Besides abrasion and impact properties, an exhaustive microstructural analysis was carried out, evaluating the carbide content, matrix phases and graphite morphology. The impact toughness was low due to the high carbide content and graphite type, but only a bit lower than that determined for similar microstructures and carbide content with spheroidal graphite (PCDI). The abrasion resistance of PCGI under the current experimental conditions (ASTM G 65 standard) was of the same level as determined for PCDI for the regions close to the cooler (<20 mm), but lower for regions located at a higher distance (>20 mm) due to the wear concentration promoted by the graphite morphology. Keywords Chilled gray iron, carbides, abrasion resistance, impact toughness