Processes for producing and casting ductile and compacted graphite cast irons

In the method of producing ductile or compacted graphite cast irons, the improvement which comprises the steps of holding molten iron that contains carbon in a vessel, treating said molten iron by adding to the molten iron bath a predominately iron alloy which as essential elements contains from about 0.1 to about 10.0% silicon by weight and from about 0.5 to about 4.0% magnesium by weight, continuing to hold said molten iron in said vessel until the magnesium from said alloy has increased the magnesium content of said treated molten iron and thereafter adding more untreated molten iron that contains carbon to said vessel along with more of said alloy to increase the magnesium content of said untreated added iron.

In the method of producing ductile or compacted graphite cast irons, the improvement which comprises the steps of holding molten iron that contains carbon in a vessel, adding to the molten iron bath an alloy predominately of iron which contains as essential elements thereof from about 0.1 to about 10.0% silicon by weight and from about 0.5 to about 4.0% magnesium by weight, reacting the magnesium of said alloy with said molten iron to increase the magnesium content of the molten iron to a selected level, continuing to hold said treated molten iron in said vessel until the magnesium content in said treated molten iron falls below the selected level and then adding more of said alloy to said molten iron to increase the magnesium content thereof at least to a selected level.

In the method of producing ductile or compacted graphite irons, the improvement which comprises the steps of holding molten iron that contains carbon and sulfur in a vessel, treating the molten iron by adding to the molten iron bath an alloy predominately of iron which contains as essential elements thereof from about 0.1 to about 10.0% silicon by weight and from about 0.5 to about 2.0% magnesium by weight, continuing to hold said treated molten iron in said vessel until the sulfur content in the treated iron is reduced and thereafter adding more of said alloy to the molten iron to increase the magnesium content thereof.

In the method of producing ductile or compacted graphite cast irons, the improvement which comprises the steps of holding molten iron that contains carbon in a vessel, agitating the molten iron to establish circulation in a downward flow in the middle of the bath, adding to the surface of the middle of the bath a predominately iron alloy which contains as essential ingredients thereof from about 0.1 to 10.0% silicon by weight and from about 0.5 to 4.0% magnesium by weight whereby the alloy is carried below the surface of the bath by the downward flow of molten iron.

In the method of producing castings of ductile or compacted graphite cast irons, the improvement which comprises flowing a stream of molten iron containing carbon into a mold and adding to the stream of molten iron as it enters the mold a predominately iron alloy which contains as essential elements thereof from about 0.1 to about 10.0% silicon by weight and from about 0.05 to about 2.0% magnesium by weight whereby the alloy is carried into the mold by the flowing stream of molten iron.

In the method of producing ductile or compacted graphite cast irons, the improvement comprising the steps of flowing a stream of molten iron containing carbon into a holding vessel, adding to said stream of molten iron a predominately iron alloy which contains from about 0.1 to about 10.0% silicon by weight and from about 0.5 to about 2.0% magnesium by weight whereby said alloy is carried by the stream of molten iron into the holding vessel and below the surface of the bath established therein.

In the method of producing castings of ductile and compacted graphite cast irons, the improvement which comprises supplying molten iron which contains carbon to at least one holding vessel, treating said molten iron by adding to the molten iron bath in the vessel a predominately iron alloy which contains as essential elements thereof from about 0.1 to about 10.0% silicon by weight and from about 0.5 to about 2.0% magnesium by weight, moving a plurality of casting molds in sequence to bring one at a time into position below said vessel to receive treated molten iron from said vessel and adding more untreated molten iron containing carbon into said holding vessel along with more of said alloy in an iron casting operation.

In the method of producing castings of ductile or compacted graphite cast irons, the improvement which comprises moving a plurality of holding vessels in a first circular path, moving a plurality of casting molds in a second circular path to bring the plurality of molds into position below said plurality of holding vessels to receive treated molten iron therefrom, establishing in said plurality of holding vessels a supply of molten iron containing carbon which has been treated with a predominately iron alloy containing as essential elements thereof by weight from about 0.1 to about 6.0% of silicon and from about 0.5 to about 2.0% magnesium, interrupting the movement of said holding vessels and molds to hold them in stationary position while at least one mold receives treated molten iron from at least one holding vessel, and re-estabishing the supply of treated molten iron in said holding vessels when held in stationary position as required for a casting operation.