# US 4,391,636 A · Method of and apparatus for the production of nodular (ductile) cast iron

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- Number: US 4,391,636 A
- Document ID: US4391636A
- Status: Granted
- Kind: A
- Application number: 06/331,163
- Filed: 1981-12-16
- Granted: 1983-07-05
- Earliest claimed: 1981-12-16
- Assignees: Wintec Co., Ltd.
- Inventors: Michael W. Windish
- Web page: https://patentgrep.com/patent/US4391636A

## CPC

- C22C 33/10: including procedures for adding magnesium
- B22D 1/00: Treatment of fused masses in the ladle or the supply runners before casting {(for continuous casting B22D11/10; metallurgical processing, e.g. refining of iron or other metal C21, C22, C25C)}
- B22D 1/007: {Treatment of the fused masses in the supply runners (B22D1/002, B22D1/005 take precedence)}
- C22C: ALLOYS (treatment of alloys C21D, C22F)
- B22D: CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES (shaping of plastics or substances in a plastic state B29C; metallurgical processing, selection of substances to be added to metal C21, C22)

## Abstract

A process or method of and apparatus for the in-ladle treatment of molten base metal iron with a nodularizing agent (e.g., a magnesium bearing alloy) so as to produce substantially uniform spheriodal graphite in the iron. The process involves placing a desired quantity of the nodularizing agent in a reaction chamber in a treatment ladle, the latter having a main chamber, a charging and filling passage leading to the reaction chamber, and one or more passages leading from the reaction chamber to the main chamber of the ladle. Molten base metal iron is then poured into the reaction chamber via the charging and filling passage thereby to effect a reaction between the nodularizing agent and the molten base metal. A hydrostatic pressure head of the molten base metal is rapidly established over the reaction chamber of sufficient depth thereby to minimize the vaporization of the nodularizing agent and to maximize the recovery of the nodularizing agent in the base metal. The base metal with the nodularizing agent dissolved and mixed therein is then permitted to flow into the main chamber via the passages. The base metal with the nodularizing agent therein is held in the main chamber for a time sufficient to convert the base metal into a matrix which when solidified is populated with spheroidal graphite. The apparatus of this invention relates to a ladle in which the above-identified process can be carried out.

## Claims

### Claim 1

A process for the production of ductile cast iron from a molten base iron which, but for the treatment of said process, would be a grey cast iron upon solidification, said process being carried out in a treatment ladle lined with a suitable refractory material, said ladle having a main chamber therein, a reaction chamber, and a charging and filling passage leading from the top of said ladle to said reaction chamber, the latter being in communication with the lower portion of the main chamber, said process comprising of the steps of:
charging said reaction chamber with a quantity of a nodularizing agent;
pouring said molten base metal into said reaction chamber via said charging and filling passage thereby to effect a reaction between said nodularizing agent and said base metals;
rapidly establishing a hydrostatic pressure head over said reaction chamber of sufficient depth thereby to maximize the recovery of said nodularizing agent in said base metal; and
permitting said base metal with the dissolved nodularizing agent therein to flow into said main chamber.

### Claim 2 (depends on 1)

A process as set forth in claim 1 further comprising of tilting said ladle so as to pour said treated molten metal from said main chamber, from said reaction chamber, and from said charging and filling passage.

### Claim 3 (depends on 1)

A process as set forth in claim 1 wherein said molten base metal flows out of said reaction chamber into said main chamber at a level below which the reaction between the nodularizing agent the base metal takes place within said reaction chamber.

### Claim 4 (depends on 1)

A process as set forth in claim 1 wherein said base metal flows down into said reaction chamber in generally horizontally out of said reaction chamber into said main chamber.

### Claim 5

An in-ladle process of treating a molten cast iron base metal with a magnesium based nodularizing agent, the ladle having a main chamber, a reaction chamber adjacent the bottom of said main chamber, a charging and filling passage leading downwardly from the top of the ladle to said reaction chamber, and one or more passages leading from said reaction chamber into said main chamber, said process comprising of the steps of:
placing a predetermined quantity of nodularizing agent in said reaction chamber;
rapidly filling said main chamber with a desired quantity of molten iron via said charging and filling passage, via said reaction chamber, and via said reaction chamber/main chamber passages;
establishing a level of said molten base metal above said nodularizing agent within said reaction chamber of sufficient depth to substantially contain the reaction between said magnesium nodularizing agent and said molten base metal so as to inhibit the escape of excess magnesium oxide to the atmosphere and so as to maximize the recovery of magnesium within the molten base metal; and
holding said molten base metal in said main chamber for a time sufficient to complete the mixing of said magnesium and said base metal.

### Claim 6 (depends on 5)

The process of claim 5 further comprising of the step of inoculating the treated base metal by introducing a suitable inoculate to promote the formation of spheroidal graphite in the treated base metal.

### Claim 7

An in-ladle process of treating molten iron base metal which, but for the treatment of said process, would be grey iron upon solidification, said process being carried out in a ladle havin a main chamber, a reaction chamber separate from and interconnected to the bottom portion of said main chamber, and a charging passage separate from said main chamber in communication from above with said reaction chamber, said process comprising of the steps of:
a placing a charge a nodularizing agent in said reaction chamber, said nodularizing agent containing a reactive substance ranging between 1 and 10% by weight of said nodularizing agent, said reactive substance being selected from magnesium, cerium, lanthanum, calcium, potassium, lithium, sodium, beryllium or yttrium;
pouring said molten base iron into said main chamber via said charging passage and said reaction chamber wherein said molten metal reacts with said reactive substance as said molten metal flows through said reaction chamber into said main chamber; and
inducing a reaction between said molten base metal and said reactive agent as said base metal flows through said reaction chamber into said main chamber wherein between 65% and 99% of said reaction agent in the nodularizing agent placed in said reaction chamber is recovered by said molten metal poured from said main chamber.

### Claim 8

An in-ladle process of treating a molten cast iron base metal with a magnesium based nodularizing agent, the ladle having a main chamber, a reaction chamber adjacent the bottom of said main chamber, a charging and filling passage leading downwardly from the top of the ladle to said reaction chamber, one or more discharge passages leading from the bottom of said reaction chamber into said main chamber, and one or more other discharge passages leading from said reaction chamber at a level above said bottom discharge passages to said main chamber, said process comprising of the steps of:
placing a predetermined quantity of nodularizing agent in said reaction chamber;
introducing molten iron into said reaction chamber via said charging and filling passage at a rate greater than said molten metal may be discharged from said reaction chamber into said main chamber via said discharge passages at the bottom of the reaction chamber;
establishing a level of said molten iron within said reaction chamber of sufficient depth to substantially contain the reaction between said nodularizing agent and said molten iron so as to dissolve said nodularizing agent into said iron, so as to inhibit the escape of said nodularizing agent to the atmosphere, and so as to maximize the recovery of said nodularizing agent within the molten iron;
after filling of said reaction chamber with molten iron to the level of said other discharge openings, discharging molten iron into said main chamber from all of said discharge openings at a rate greater than or equal to the rate at which said molten iron may be introduced into said reaction chamber via said charging and filling passage; and
holding said molten iron in said main chamber for a time sufficient to complete the mixing of said magnesium and said base metal.

### Claim 9

Apparatus for the treatment of a molten ferrous based metal which, but for treatment, would form grey cast iron upon solidification, said apparatus comprising a ladle having a structural shell, means for supporting said ladle and for selectively tilting the ladle for pouring the treated metal therefrom, a refractory liner within said shell, said refractory liner defining a main chamber, a reaction chamber proximate to the lower portion of said main chamber, one or more discharge passages providing communication between the reaction chamber and said main chamber, and a charging passage leading downwardly to said reaction chamber, said reaction chamber being sized so as to contain a sufficient quantity of said nodularizing agent, the latter being reactive with said molten base metal as the latter is poured into said charging and filling passage.

### Claim 10 (depends on 9)

Apparatus as set forth in claim 9 having at least two of said discharge passages between said reaction chamber and said main chamber, at least one of said discharge passages being in communication with the bottom of said reaction chamber and with said main chamber, this last-said at least one discharge passage having a choked flow area such that the discharge rate of molten metal from said reaction chamber into said main chamber via said at least one discharge passage is less than the filling rate of said reaction chamber via said charging passage, and at least one other of said discharge passages being in communication with the upper portion of said reaction chamber and being operable to discharge molten iron into said main chamber only after said reaction chamber has been at least substantially filled with molten metal, the combined flow areas of all of said discharge passages being greater than or equal to the minimum cross sectional area of said charging passage so that the flow of molten metal from said reaction chamber into said main chamber via all of said discharge passages is equal to or greater than the flow of molten metal into said reaction chamber via charging passage.