# US 4,292,075 A · Slow fade inocculant and a process for the inocculation of melted cast iron

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- Number: US 4,292,075 A
- Document ID: US4292075A
- Status: Granted
- Kind: A
- Application number: 06/090,719
- Filed: 1979-11-02
- Granted: 1981-09-29
- Earliest claimed: 1978-11-03
- Assignees: SKW Trostberg Aktiengesellschaft; Halbergerhutte GmbH
- Inventors: Friedrich Wolfsgruber; Hans W. Kasel; Manfred H. A. Odendahl; Wolfram W. Morsdorf
- Web page: https://patentgrep.com/patent/US4292075A

## CPC

- C21C 1/10: Making spheroidal graphite cast-iron
- C21C 1/08: Manufacture of cast-iron
- C21C: PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS

## Abstract

A slow fade cast iron inocculant is made up of (a) a silicon-containing matrix of iron silicon alloys and having a crystal structure, (b) compounds, present in the matrix crystal structure, of high-melting point calcium aluminum silicates, generally in the form CaO.Al.sub.2 O.sub.3.2SiO.sub.2 +Al.sub.2 O.sub.3.2SiO.sub.2, and (c) a dicalcium aluminum silicate material with up to 20% by weight of silicon carbide and 10% by weight of calcium carbide. The relation between the matrix and the high-melting point calcium aluminum silicates to the dicalcium silicate material is about 1 to 0.05-0.2. The amount of high-melting point calcium aluminum silicates in the matrix is 5 to 30% by weight and, more specially 8 to 15% by weight.

## Claims

### Claim 1

An inocullant for melted cast iron comprising:
(a) a silicon-containing matrix of iron-silicon alloys and having a crystal structure,
(b) a high-melting point calcium aluminum silicate compound, present in the matrix crystal structure, and
(c) a dicalcium aluminum silicate material with up to 20% by weight of silicon carbide and up to 10% by weight of calcium carbide,
the weight ratio of the calcium-containing matrix with the high-melting point calcium aluminum silicate to the dicalcium silicate material being about 1:0.05 to about 1:0.2 and the amount of high-melting point calcium aluminum silicate in the silicon-containing matrix being 5 to 30% by weight.

### Claim 2 (depends on 1)

The inocculant of claim 1, wherein said high-melting point calcium aluminum silicate is CaO.Al.sub.2 O.sub.3.2SiO.sub.2 +3Al.sub.2 O.sub.3.2SiO.sub.2.

### Claim 3 (depends on 1)

The inoccculant of claim 1, wherein the amount of high-melting point calcium aluminum silicate in the silicon-containing matrix is 8 to 15% by weight.

### Claim 4 (depends on 1)

A process for the inocculation of melted cast iron, comprising adding an inocculant as claimed in claim 1 in an amount of 0.05 to 1% by weight to the melted cast iron.

### Claim 5 (depends on 4)

A process as claimed in claim 4, comprising adding said inocculant in an amount of 0.1 to 0.5% by weight.

### Claim 6 (depends on 4, 5)

A process as claimed in claim 4 or claim 5, comprising adding said inocculant to the cast iron in an apparatus for keeping it in a melted condition, in and before the apparatus or to the melted cast iron in the forehearth.

### Claim 7 (depends on 4, 5)

A process as claimed in claim 4 or claim 5, comprising adding said inocculant to the burden or a material of the burden before melting, in an amount of 0.05 to 4% by weight.

### Claim 8 (depends on 4, 5)

A process as claimed in claim 4 or claim 5, said process producing nodular or vermicular graphite cast iron by conditioning melted cast iron with magnesium and/or rare earth elements and said process comprising, right after this conditioning step, further adding said inocculant in amount of 0.1 and 0.7% by weight.

### Claim 9 (depends on 6)

A process as claimed in claim 6, said process producing nodular or vermicular graphite cast iron by conditioning melted cast iron with magnesium and/or rare earth elements and said process comprising, right after this conditioning step, further adding said inocculant in amount of 0.1 and 0.7% by weight.

### Claim 10 (depends on 7)

A process as claimed in claim 7, said process producing nodular or vermicular graphite cast iron by conditioning melted cast iron with magnesium and/or rare earth elements and said process comprising, right after this conditioning step, further adding said inocculant in amount of 0.1 and 0.7% by weight.

### Claim 11 (depends on 8)

A process as claimed in claim 8, wherein the amount of the inocculant is 0.2 to 0.4% by weight.

### Claim 12 (depends on 9)

A process as claimed in claim 9, wherein the amount of the inocculant is 0.2 to 0.4% by weight.

### Claim 13 (depends on 10)

A process as claimed in claim 10, wherein the amount of the inocculant is 0.2 to 0.4% by weight.

### Claim 14 (depends on 11)

A process as claimed in claim 11, wherein the amount of the inocculant is 0.2 to 0.4% by weight.