Improvement of ductile iron wear resistance through local surface reinforcement

B. Podgornik, J. Vižintin, I. Thorbjornsson, B. Johannesson, J. T. Thorgrimsson, M. Martinez Celis, N. Valle

Wear 274/275 (2012) 267-273.


Ductile iron (DI) or spheroidal graphite cast iron is an attractive ferrous material being widely used due to its combination of low cost and good combination of strength toughness and fatigue endurance. However, under severe service conditions, experienced in seashore, earth-moving and mining application the performance and reliability of DI are limited due to its poor wear resistance. Wear resistance of DI can be improved through different heat treatment and surface engineering techniques, each having some limitations and drawbacks. Recently, a new method called OPTICA has been introduced, which through local reinforcement with inserts improves wear resistance of ductile iron without compromising other properties. Results of the present investigation show that tribological properties of ductile iron can be greatly improved by local surface reinforcement. Through the formation of carbides a hard transition or functional gradient zone is formed around the inserts, which then carries the load and improves wear resistance of ductile iron, at the same time maintaining low friction. However, wear resistance of reinforced ductile iron can be improved even further, using proper austempering process. If austempered at 350 °C, wear resistance of ductile iron will become comparable or even better than reference Hadfield grade steel. In this paper reinforced or reinforcement refers to locally alloyed material in preselected zones of the casted object if not specified otherwise.

Keywords: local alloying, reinforcement, ductile iron, friction, wear


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