Showing papers on "Gray iron published in 1979"

Coke for use in the production of gray iron; method of producing said coke and method of producing gray iron by using said coke

Abstract: An effective amount of silicon carbide, preferably mixed with graphite, is added to the blend of coals used to make a foundry coke, the blend is thoroughly mixed, pulverized, and coked in a by-product coke oven. The resulting coke has improved physical and chemical properties allowing production of gray iron with less fuel. Gray iron castings with improved hardness control at lower cost are produced by the inoculating effect of the silicon from silicon carbide and graphite in the mixture.

Abrasive Wear of Microstructures with Internal Notches

Abstract: The influence of microcracks, lamellar o:: spherical graphite and large carbides in the microstructure on abrasive wear was investigated using a tool steel, gray iron, ductile iron and white irons. All materials exhibited internal stresses and low fracture toughness. Abrasive wear rate on commercial abrasive paper was determined using the pin-on-disk method. The results show that internal notches increase the abrasive wear rate of relatively brittle materials. Beside pure grooving wear, large wear particles can break out of the stressed surface (spalling) due to local crack propagation at internal notches.

Role of interphase boundary adsorption in formation of spheroidal graphite in cast iron

Abstract: The interphase boundaries in gray and ductile cast iron were studied with a scanning Auger microprobe (SAM). Sulfur and oxygen were found to be adsorbed at the flake/ metal interfaces in the gray iron, while the nodule/metal and intercrystalline graphite interfaces in the ductile iron were free of foreign elements. The only magnesium detected in the magnesium modified ductile iron was combined with phosphorus and sulfur as a compound. A model is presented which proposes that Fe−C−Si eutectic alloys in the absence of surface active impurities (such as in vacuum casting of high purity materials) produce nodular graphite due to the inherent instability of the graphite/melt interface. The sulfur and oxygen always present in commercial alloys adsorb at the graphite/melt interface, effectively “stabilizing” the active sites on the graphite basal planes, and preventing spherulitic growth. The purpose of modifiers is to getter these impurities.