Wear Resistance Of Cast Steel Research Articles

Influence of Ni content on impact-abrasion wear resistance of medium-carbon low alloy cast steel

Medium-carbon low alloy wear-resistant cast steel with different Ni contents (0.08 mass%, 0.77 mass%, 1.74 mass%, 2.43 mass%) were heat treated at 1050 °C, followed by water quenching and tempering at 250 °C. The influence of Ni content on the microstructure, hardness, impact toughness and abrasive resistance of the cast steel were investigated. The results showed that the Ni contents increasing hindered the transformation of martensite phase by reducing martensite transformation start temperature (Ms) and martensite transformation finish temperature (Mf). The fine martensite phase after quenching improved the hardness, impact toughness and wear-resistance of the cast steel. The cast steel with low Ni content (0.08% or 0.77%) consists of lath tempered martensite, while the microstructure turns to mixed lath martensite and lamellar twin martensite with higher Ni content. The cast steel with 1.74% Ni showed a hardness of HRC49.5, an impact absorbing energy with V-notch impact absorbing energy of 16.7 J, and the best wear resistance among the samples.

鋳鋼による超硬合金粉末の鋳ぐるみとその組織および硬さの評価

In order to improve wear resistance of cast steel, hard alloy powder layer was inserted by molten cast steel at 1843K. The vertical cross-section of the inserted layer was examined on the microstructure and the hardness. The results obtained are as follows. Sound inserted layer of 3mm in thickness was confirmed to be formed without any defects on the surface of cast steel.A reaction layer with some lump shaped particles was formed in the interface between the inserted layer and the mother metal (cast steel). The lump shaped particles were identified to be Fe3W3C phase which had a cubic structure with a lattice constant of 11.1094×10-8cm. The particles were considered to be formed by a reaction between the Co bond phase dissolving WC in hard alloy powder and the molten iron dissolving low concentration of C in molten steel. The hardness of cast steel was about Hv300, while the inserted layer exihibited high hardness of Hv600 to 800.Especially, the reaction layer showed peak hardness of Hv1800, but the layer was not brittle. The toughness of the reaction layer was considered to be due to a mixed structure of tough bainite and retained austenite around the hard Fe3W3C particles. The present method using the inserted hard alloy powder layer is therefore to be very effective one for local hard facing of cast steel.

Effect of alloying on the wear resistance of cast steel

We study the influence of rare-earth metals on physicomechanical properties and wear resistance of cast tool steel and establish the optimal content of carbon (0.55–0.65%) which guarantees sufficiently high abrasive wear resistance of steel. Alloying with titanium, niobium, and rare-earth metals improves wear resistance of steels, especially with elevated contents of carbon.