JP-2026514215-A - Metalworking additives

Abstract

A metal treatment additive for treating molten iron, comprising 10 to 90% by weight of an activator and 90 to 10% by weight of a carrier. The activator mainly comprises one or more of barium, bismuth, and zirconium, and the additive composition contains less than 0.5% by weight of magnesium. The additive is suitable for inoculating molten iron during the casting process. [Selection Diagram] Figure 1

Inventors

• パウエル，コリン
• ステッツ，ウルフラム
• トロシェル，ウルフギャング

Assignees

• フォセコ インターナショナル リミテッド

Dates

Publication Date

20260507

Application Date

20240405

Priority Date

20230406

Claims (15)

1. An inoculant composition for processing molten iron, 10-90% by weight of the activator, Including 90-10% by weight of carrier, The aforementioned activator contains one or more of the following as its main components: barium, bismuth, manganese, and zirconium. The aforementioned inoculant composition is an inoculant composition containing less than 0.5% by weight of magnesium.
2. The activator comprises 3 to 40% by weight of zirconium, as described in any one of the preceding claims.
3. The inoculant composition according to claim 2, wherein the activator contains 3 to 25% by weight of bismuth.
4. The inoculant composition according to claim 2 or 3, wherein the activator contains 0.3 to 22% by weight of manganese.
5. The inoculant composition according to claim 1, wherein the activator contains 20 to 40% by weight of barium.
6. The activator comprises 0 to 10% by weight of calcium, as described in any one of the preceding claims.
7. The inoculant composition contains less than 0.5% by weight of carbon, less than 0.1% by weight of sulfur, and/or less than 0.5% by weight of phosphorus.
8. The carrier comprises ferrosilicon, as described in any one of the preceding claims.
9. The inoculant composition according to any one of the preceding claims, wherein the inoculant composition is formed into a powder, granules, and/or tablets, and optionally, the inoculant composition is provided in pre-divided packages.
10. The inoculant composition according to claim 9, wherein the inoculant composition has a particle size of 0.2 mm to 12 mm.
11. A method of inoculating with molten iron, Supplying the inoculant composition described in any one of the preceding claims into a container, A method comprising adding molten iron to the aforementioned container.
12. A method for inoculating molten iron, comprising spraying an inoculant composition according to any one of claims 1 to 10 into a flow of molten iron.
13. The method according to claim 11 or claim 12, comprising adding less than 0.5% by weight of the inoculant composition relative to the weight of molten iron.
14. A method for producing an inoculant composition according to any one of claims 1 to 10, This involves reacting silica, iron, and carbon in a submerged arc furnace to form ferrosilicon and carbon dioxide, or remelting a ferrosilicon alloy in an induction furnace. Adding one or more activators to the furnace to produce an inoculant composition containing the activators and ferrosilicon alloyed with them, The inoculant composition is cooled and solidified, A method comprising grinding the aforementioned inoculant composition to produce a granular and/or powdered inoculant composition.
15. The method according to claim 14, further comprising mixing the granular and/or powdered inoculant composition with a further granular and/or powdered activator.

Description

This invention relates to a method for processing molten metal. In particular, it relates to the processing of molten iron, and to systems and compositions for processing molten iron. Metallurgical agents are used to modify the composition, morphology, and/or distribution of graphite particles found in molten iron. Metallurgical agents applied to molten iron include nodularising agents and inoculants, which are used to alter the morphology of the iron structure, thereby producing ductile iron (DI) and compact iron graphite (CGI). Inoculants are additives that introduce nuclei into the molten iron, acting as crystallization sites for dissolved carbon. These crystallization sites alter graphite precipitation and the formation of the casting's structure. Insufficient inoculation can lead to the formation of undesirable iron carbide in the casting as the iron cools. Many existing inoculant alloys are based on ferrosilicon as a carrier, with the addition of "active agents" such as calcium, aluminum, barium, zircon, strontium, and rare earth metals. During inoculation of molten cast iron, the oxygen and/or sulfur contained within it binds, either fully or partially, to the active agents in the inoculant composition, crystallizing as oxides, sulfides, or oxysulfides. These ultramicroscopic chemical compounds/crystallized products act as crystal nuclei for the crystallization of graphite particles in the solidifying cast iron. The inoculant composition itself is provided as a powder or granular material having particles with an average size ranging from 0.2 mm to 15 mm or less. In a typical inoculation process, the amount of inoculant composition required is very small. For example, even with a relatively high addition rate of 0.4–0.5% by weight of the inoculant composition relative to the weight of the iron being processed, this amounts to only 4–5 kg per metric tonne of metal. Furthermore, conventional inoculant compositions have an activator concentration of approximately 5%, which corresponds to an addition rate of approximately 250 g of activator per metric tonne of iron. Moreover, to keep costs low, it is desirable to use the minimum possible weight of material. However, such low addition rates present significant problems when mixing the inoculant into the molten iron. For example, the inoculant may be supplied to the ladle before the molten iron is poured into it. If the weight/volume of the inoculant composition is small, if some of the powder remains in the corners of the ladle during processing, the entire volume of the ladle may be insufficiently inoculated. In the case of in-stream inoculation, small amounts of inoculant are difficult to control, and if not all of the inoculant enters the flow of metal, insufficient inoculation will result. Insufficient inoculation (e.g., as a result of poor mixing) leads to poor crystalline structure formation and costly casting defects. To improve mixing, inoculants are typically 90% ferrosilicon-based, with ferrosilicon acting as a soluble carrier. That is, the active ingredient in such a ferrosilicon-based inoculant only needs to account for 10% of the total weight or volume of the inoculant composition. A lower concentration of the composition means that a larger amount of composition is required, but this leads to a larger tolerance for error and improved mixing of the molten material. However, this increases the costs of manufacturing, transporting, and using the inoculant composition. Therefore, it is desirable to provide alternative inoculant compositions that mitigate or improve one or more problems related to existing inoculant compositions and inoculation processes. According to a first aspect of the present invention, an inoculant composition for treating molten iron is provided. The inoculant composition may contain 10 to 90% by weight of an activator. The inoculant composition may contain 90 to 10% by weight of a carrier. The activator may contain, as a main component, one or more of barium, bismuth, manganese, and zirconium. The inoculant composition may contain less than 0.5% by weight of magnesium. As used herein, the term "primary component" refers to the element or compound that has the highest addition rate, e.g., the highest weight percentage, within the activator. The activator may contain one or more additional components. Iron and silicon, either individually or as a ferrosilicon alloy, are not considered activators. All weight percentages used herein refer to the entire inoculum composition unless otherwise specified. The activator may contain 3 to 40% by weight of zirconium (relative to the total weight of the inoculum composition). The activator may contain at least 4, 5, 6, 7, 8, 9, 10, 12, 14, 15, 16, 18, 20, 22, 24, 25, 26, 28, 30, 32, 34, 35, 36, or 38% by weight of zirconium. The activator may also contain 38, 36, 35, 34, 32, 30, 28, 26, 25, 24, 22, 20, 18, 16, 15, 14, 12, 10, 9, 8, 7, 6, 5, or less than 4% by weight of zirconium. In so