Metal treatment additive

Abstract

A metal treatment additive for treating molten iron, the metal treatment additive comprising 10 to 90% by weight of an active agent and 90 to 10% by weight of a carrier. The active agent comprises one or more of barium, bismuth, and zirconium as a major component, and the additive composition comprises less than 0.5 wt% magnesium. The additive is suitable for inoculating molten iron in a casting process.

Description

Technical Field

[0001] This invention relates to methods for processing molten metal. In particular, this invention relates to systems and compositions for processing molten iron.

[0002] background

[0003] Metal treatment agents are used to alter the composition, morphology, and / or distribution of graphite particles found in molten iron. Metal treatment agents applied to molten iron include spheroidizing agents and inoculants, used to modify the morphology of the iron structure, thereby producing ductile iron (DI) and compacted graphite iron (CGI). An inoculant is an additive that introduces nuclei into the molten iron, acting as crystallization points for carbon dissolved in the iron – these crystallization points alter graphite precipitation and the formation of the casting structure. Poor inoculation can lead to the formation of undesirable iron carbides in the casting as the iron cools.

[0004] Most existing inoculants are alloys based on ferrosilicon with added "activators" such as calcium, aluminum, barium, zirconium, strontium, and rare earth metals. During the inoculation of molten cast iron, the oxygen and / or sulfur contained within it combine wholly or partially with the activators in the inoculant composition, precipitating as oxides, sulfides, or oxysulfides. These submicroscopic chemical compounds / precipitates act as nuclei for the precipitation of graphite particles in the cast iron during the curing process. The inoculant composition itself is provided as a powder or granular material, with an average particle size ranging from 0.2 mm to up to 15 mm.

[0005] During typical inoculation processes, the required amount of inoculant composition is very low; for example, a relatively high addition rate of 0.4 to 0.5% by weight of the iron being treated would only require 4 to 5 kg per ton of metal. Furthermore, conventional inoculant compositions contain an activator concentration of approximately 5%, equivalent to an addition rate of approximately 250 grams of activator per ton of iron. Additionally, to maintain low costs, it is desirable to use minimal materials. However, at such low addition rates, significant problems arise in the mixing of the inoculant with the molten iron. For example, the inoculant may be added to the ladle before the molten iron is poured into it. Due to the low weight / volume ratio of the inoculant composition, if some powder remains trapped in a corner of the ladle during processing, the entire volume of the ladle may be insufficiently inoculated. For in-stream inoculation, controlling the low dosage of inoculant is also problematic; inoculation will be incomplete unless all the inoculant enters the metal stream.

[0006] Inadequate inoculation (e.g., due to poor mixing) can lead to poor crystal structure formation and costly casting failures. To improve mixing, inoculants are typically 90% ferrosilicon-based, with ferrosilicon acting as a soluble carrier; that is, the active ingredient in such ferrosilicon-based inoculants may only account for 10% of the total weight or volume of the inoculant composition. Low concentrations mean a larger volume of composition is required, but this also provides greater tolerance and improved mixing through the melt. However, this increases the production, transportation, and use costs of the inoculant composition.

[0007] Therefore, it is desirable to provide an alternative probiotic composition to alleviate or improve one or more problems associated with existing probiotic compositions and probiotic processes. Invention Overview

[0009] According to a first aspect of the 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 one or more of barium, bismuth, manganese, and zirconium as a main component. The inoculant composition may contain less than 0.5% by weight of magnesium.

[0010] As used herein, the term "major component" refers to the element or compound that is added in the highest proportion (e.g., by weight) in the surfactant. Surfactants may also contain one or more other components. Iron and silicon, whether alone or as ferrosilicon alloys, are not considered surfactants.

[0011] Unless otherwise stated, all weight percentages used herein refer to the total progesterone composition.

[0012] The activator may contain 3-40% by weight of zirconium (relative to the total weight of the inoculant composition).

[0013] 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 contain less than 38, 36, 35, 34, 32, 30, 28, 26, 25, 24, 22, 20, 18, 16, 15, 14, 12, 10, 9, 8, 7, 6, 5, or 4% by weight of zirconium.

[0014] In some embodiments, the activator comprises 3 to 25 wt% zirconium. For example, in some embodiments, the activator comprises 4 to 6 wt%, 8 to 15 wt%, 10 to 12 wt%, or 18 to 22 wt% zirconium. In a further series of embodiments, the activator comprises 25 to 40 wt%, and optionally, 30 to 35 wt% zirconium.

[0015] The active agent may contain 3-25% by weight of bismuth (relative to the total weight of the inoculant composition). The active agent may contain at least 4, 5, 6, 7, 8, 9, 10, 12, 14, 15, 16, 18, 20, 22, or 24% by weight of bismuth. The active agent may contain less than 24, 22, 20, 18, 16, 15, 14, 12, 10, 9, 8, 7, 6, 5, or 4% by weight of bismuth. In some embodiments, the active agent contains 4 to 6% by weight, or 5 to 15% by weight of bismuth.

[0016] The active agent may contain 5-40% by weight of barium (relative to the total weight of the probiotic composition). The active agent may contain at least 22, 24, 25, 26, 28, 30, 32, 34, 35, 36, or 38% by weight of barium. The active agent may contain at least 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 barium. The active agent may contain less than 38, 36, 35, 34, 32, 30, 28, 26, 25, 24, 22, 20, 18, 16, 15, 14, 12, 10, 9, 8, 7, or 6% by weight of barium. In some embodiments, the active agent contains 5 to 15% by weight of barium, or 10 to 12% by weight of barium. In some further embodiments, the activator comprises 30 to 40% by weight of barium, for example 34 to 36% or 35% by weight of barium.

[0017] The progesterone composition may contain minor active agents and / or minor components. In some embodiments, the progesterone composition contains multiple active agents. As mentioned above, the primary component is the active agent added at the highest rate in the progesterone composition. Therefore, minor active agents provide additional progesterone effects.

[0018] Secondary components may include compounds or materials that do not have a prebiotic effect and / or compounds or materials selected due to other useful properties or effects on the prebiotic composition.

[0019] The active agent may contain 0-10% by weight of calcium (relative to the total weight of the probiotic composition). The active agent may contain at least 0.2, 0.3, 0.5, 1, 1.5, 2, 3, 4, 5, 6, 7, 8, or 9% by weight of calcium. The active agent may contain less than 9, 8, 7, 6, 5, 4, 3, 2, 1.5, 1, 0.5, 0.3, or 0.2% by weight of calcium. In some embodiments, the active agent contains 0-5% by weight, optionally 0.5 to 2% by weight of calcium. In some embodiments, the active agent contains 1 to 7% by weight, optionally 1-2% by weight of calcium. Calcium may be present as a minor active agent or a minor component.

[0020] The surfactant may further comprise 0 to 5% by weight of aluminum. The surfactant may comprise at least 0.5, 1, 1.5, 2, 3, or 4% by weight of aluminum. The surfactant may comprise less than 4, 3, 2, 1.5, 1, or 0.5% by weight of aluminum. In some embodiments, the surfactant comprises 1 to 2% by weight of aluminum. In some embodiments, the surfactant comprises no more than 1.5% by weight of aluminum. Aluminum may be present as a minor surfactant or minor component.

[0021] In some embodiments, aluminum and / or calcium may originate from their inclusions in other minerals or components. For example, aluminum and / or calcium are commonly found in sources of barium and other minerals, especially natural minerals. In some embodiments, additional aluminum or calcium may be added to the inoculant composition in addition to the amounts naturally present in other components.

[0022] The inoculant composition may contain 0-22% by weight of manganese (relative to the total weight of the inoculant composition). The inoculant composition may contain at least 0.2, 0.3, 0.5, 1, 1.5, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 14, 15, 16, 18, or 19% by weight of manganese. The inoculant composition may contain less than 19, 18, 16, 15, 14, 12, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1.5, 1, 0.5, 0.3, or 0.2% by weight of manganese. In some embodiments, the inoculant composition contains 0.3 to 20% by weight, 0.3 to 15% by weight, or 10 to 12% by weight of manganese. Manganese may be present as a minor component. Manganese effectively lowers the melting point of the inoculant composition alloy, thereby improving the processing.

[0023] In a series of embodiments (in conjunction with the above), the activator comprises 8 to 15 wt% zirconium and 0.3 to 15 wt% manganese. In another series of embodiments, the activator comprises 25 to 40 wt% zirconium and 0.3 to 20 wt% manganese. In some embodiments, the activator comprises no more than 1.5 wt% aluminum. Due to the low solubility of zirconium in molten iron, alloys of zirconium, such as those with manganese or other metals, are particularly desirable.

[0024] In a range of embodiments (in conjunction with the foregoing), the activator comprises 3 to 25 wt% zirconium and 3 to 25 wt% bismuth. For example, the activator may comprise 4 to 6 wt% zirconium and 4 to 6 wt% bismuth. The activator may optionally comprise 0 to 5 wt% manganese. The activator may comprise 0 to 5 wt% aluminum, and optionally, 1 to 2 wt% aluminum. In some embodiments, the activator comprises 18 to 22 wt% zirconium and 5 to 15 wt% bismuth. The activator may comprise 0 to 22 wt% manganese. The activator may comprise 0 to 5 wt% aluminum, and optionally, 1 to 2 wt% aluminum.

[0025] In a range of embodiments (in conjunction with the above), the activator comprises 20 to 40 wt% barium and 0 to 10 wt% calcium. In some embodiments, the activator comprises 30 to 35 wt% barium and 1 to 6 wt% calcium. In some embodiments, the activator comprises no more than 1.5 wt% aluminum.

[0026] The inoculant composition may contain 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.

[0027] The carrier may include iron, silicon, and / or ferrosilicon. The carrier may contain 10 to 70% by weight of silicon (relative to the total weight of the inoculant composition) and may be silicon or ferrosilicon. The carrier may contain at least 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, or 65% by weight of silicon. The carrier may contain less than 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, or 15% by weight of silicon. In some embodiments, the carrier contains 10 to 20% by weight of silicon. In some embodiments, the carrier contains 45 to 60% by weight of silicon.

[0028] The balance of the inoculant composition may contain iron, which may be ferrosilicon or iron. In some embodiments, the carrier contains 18 to 85% by weight of iron. The carrier may contain at least 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, or 80% by weight of iron. The carrier may contain less than 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, or 15% by weight of iron. In some embodiments, the carrier contains 19 to 50% by weight of iron, 30 to 55% by weight of iron, or 24 to 85% by weight of iron.

[0029] In embodiments containing ferrosilicon, the ferrosilicon contains 50-70% silicon, and preferably 60-70% silicon. These alloys are advantageous because they have the lowest melting point of all ferrosilicon alloys, approximately 1100°C. Cast iron requires a small amount of silicon, so it generally does not cause problems as long as the silicon content is kept below certain limits. High silicon additions can lead to remelting problems in the iron.

[0030] The inoculant composition can be formed as a single alloy containing all of its components.

[0031] The probiotic composition can be formulated as powder, granules, and / or tablets. In some embodiments, the probiotic composition is packaged in a pre-filled package. The pre-filled package may contain powder, granules, and / or tablets. The pre-filled package may contain paper or cardboard material, metal foil, and / or plastic material filled with the probiotic composition.

[0032] In some embodiments, the probiotic composition is disposed within a cored wire. The wire may include an outer iron or steel tube filled with the probiotic composition.

[0033] The probiotic composition may comprise particles or granules with a size of 0.2 mm to 12 mm. For example, the probiotic composition may comprise 90% particles or granules falling within the range of 0.2 mm to 12 mm. In some embodiments, the particle size may be 0.2 to 0.7 mm. Such fine particles are ideally suited for use in in-flow inoculation systems. In some embodiments, the particle or granule size may comprise 0.2 to 2 mm, 2 to 6 mm, and / or 6 to 12 mm.

[0034] According to a second aspect of the invention, a method for inoculating molten iron is provided. The method may include providing an inoculant composition described herein to a container. The method may include adding molten iron to the container. The container may be a molten iron ladle car. The method may include adding an inoculant composition of no more than 0.5% by weight relative to the weight of the molten iron to be treated. In some embodiments, the method includes adding an inoculant composition of less than 0.45, less than 0.4, less than 0.35, 0.3, 0.25, 0.2, 0.15, 0.1, 0.8, 0.6, 0.5, 0.4, 0.2, 0.1, 0.08, 0.06, 0.05, 0.04, or 0.02% by weight relative to the weight of the molten iron.

[0035] The inventors have discovered that this invention can inoculate molten iron and provide high-quality castings even at much lower addition rates. Significant cost savings can be achieved by reducing the amount of inoculant composition required to inoculate the melt. Although the inoculant composition itself is expensive to produce, it is more cost-effective for foundries at lower addition rates while maintaining high quality.

[0036] In some embodiments, the method may include stirring molten iron, for example using a rotor. In some embodiments, the method may include supplying an inoculant composition to the molten iron via a rotor.

[0037] In a third aspect of the invention, a method for inoculating molten iron is provided, the method comprising injecting the inoculant composition described herein into a stream of molten iron. The method may include injecting the inoculant composition into a stream of molten metal between a ladle car and a mold.

[0038] In a fourth aspect of the invention, a method for producing the inoculant composition described herein is provided. The method may include: reacting silica, iron, and carbon in a submerged arc furnace to produce ferrosilicon and carbon dioxide, or remelting a ferrosilicon alloy in an induction furnace. The method may include adding one or more activators to the furnace to form an alloy inoculant composition comprising a carrier and an activator. The method may include cooling and solidifying the inoculant composition. The method may include pulverizing the inoculant composition to produce a granular and / or powdered inoculant composition.

[0039] The method may include pulverizing the progesterone composition to a particle size and / or part size between 0.2 mm and 12 mm, or within the aforementioned range. The method may include removing particles smaller than 0.2 mm.

[0040] The method may further include mixing the granular and / or powdered probiotic composition with another granular and / or powdered surfactant. The method may also include mixing the granular and / or powdered probiotic composition with another carrier.

[0041] The embodiments of the present invention will now be described with reference to the following experimental data.

[0042] Experiment – ​​Casting Test

[0043] Several powdered probiotic compositions E1 to E5 were prepared according to Table 1:

[0044] Table 1 - Composition of progestins

[0045]

[0046] In a series of tests, E1 to E5 were weighed to predetermined weights and wrapped in aluminum foil to form pre-packaged ladles. These pre-packaged ladles were added to the top of a ladle car containing 360 kg of molten iron. The addition rates of E1 to E5 ranged from 0.23% to 0.06% by weight of the molten iron. As a comparative example, 0.7% by weight of C1 was added to the ladle car containing 360 kg of molten iron. The inoculated iron was then poured into a mold and cooled.

[0047] Excellent zirconium recovery rates between 60% and 70% were found in tests using compositions E1, E2, and E5. The “recovery rate” of a metal refers to the amount present in the final casting that is not lost during the casting process, and is therefore a measure of efficiency.

[0048] Then, samples of each casting were taken from both the thin-walled and thick-walled sections and prepared for metallographic examination. The examination images of the thin-walled sections are shown below. Figure 1 As shown, the inspection image of the thick-walled section is as follows. Figure 2 As shown in the figure. Other test data are shown in Table 2 below.

[0049] Table 2 - Results of Metallographic Examination

[0050]

[0051] As mentioned above Figure 1 , Figure 2 As shown in Table 2, the experimental results indicate that the addition rates of E1 and E3 can be only half that of the standard product. The addition rates of E2 and E4 can be only one-quarter that of the standard product.

[0052] The inventors also surprisingly discovered that the inoculant composition E5 (compared to commercial inoculant products containing 4% Zr, 3% Mn, 1.2% Ca, 1% Al and the balance being ferrosilicon (62-69% Si)) improved the performance of castings (e.g., fewer casting defects) and had a lower cooling rate when the wall thickness was greater than 50 mm.

[0053] Although the addition rates of the example compositions E1 to E5 were much lower, all test compositions E1 to E5 were comparable to the control compositions.

Claims

1. An inoculant composition for treating molten iron, said composition comprising: 10 to 90% by weight of active agent; and 90 to 10% by weight of the carrier, in, The activator contains one or more of barium, bismuth, manganese, and zirconium as its main components, and The inoculant composition contains less than 0.5% by weight of magnesium.

2. The inoculant composition according to any one of the preceding claims, wherein the active agent comprises 3-40% by weight of zirconium.

3. The inoculant composition according to claim 2, wherein the active agent comprises 3-25% by weight of bismuth.

4. The probiotic composition according to claim 2 or 3, wherein the active agent comprises 0.3-22% by weight of manganese.

5. The probiotic composition according to claim 1, wherein the active agent comprises 20-40% by weight of barium.

6. The progesterone composition according to any one of the preceding claims, wherein the active agent comprises 0-10% by weight of calcium.

7. The inoculant composition comprising 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 inoculant composition according to any one of the preceding claims, wherein the carrier comprises ferrosilicon.

9. The progesterone composition according to any one of the preceding claims, wherein the progesterone composition is formed as a powder, granules and / or tablets, and optionally, wherein the progesterone composition is disposed in a pre-packaged package.

10. The probiotic composition according to claim 9, wherein the particle size or particulate size of the probiotic composition is from 0.2 mm to 12 mm.

11. A method for inoculating molten iron, the method comprising: Provide the progesterone composition according to any one of the preceding claims to a container, Add molten iron to the container.

12. A method for inoculating molten iron, the method comprising injecting an inoculant composition according to any one of claims 1 to 10 into a stream of molten iron.

13. The method of claim 11 or claim 12, wherein the method comprises adding less than 0.5% by weight of the inoculant composition relative to the molten iron.

14. A method for producing a progestin composition according to any one of claims 1 to 10, the method comprising: Silicon dioxide, iron, and carbon react in a submerged arc furnace to produce ferrosilicon and carbon dioxide, or ferrosilicon alloy is remelted in an induction furnace. One or more activators are added to the furnace to form an inoculant composition comprising ferrosilicon alloyed with the activators; The inoculant composition is cooled and solidified. and The probiotic composition is pulverized to produce a granular and / or powdered probiotic composition.

15. The method of claim 14, the method further comprising mixing the granular and / or powdered probiotic composition with an additional granular and / or powdered surfactant.

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