High-carbon iron-based amorphous alloy using molten pig iron and method of manufacturing the same

Abstract

Provided is an iron-based amorphous alloy and a method of manufacturing the same. More particularly, provided is an high carbon iron-based amorphous alloy expressed by a general formula Fe.sub.C.sub.SiBxPyCrz, wherein , , , x, y and z are atomic % of iron (Fe), carbon (C), silicon (Si), boron (B), phosphorus (P), and chrome (Cr) respectively, wherein is expressed by =100(++x+y+z) atomic %, is expressed by 13.5 atomic %17.8 atomic %, is expressed by 0.30 atomic %1.50 atomic %, x is expressed by 0.1 atomic %x4.0 atomic %, y is expressed by 0.8 atomic %y7.7 atomic %, and z is expressed by 0.1 atomic %z3.0 atomic %.

Claims

1. A method of manufacturing a high carbon iron-based amorphous alloy comprising: preparing molten pig iron containing carbon (C) of at least 13.5 atomic %; adding at least one of FeSi alloy, FeB alloy, FeP alloy and FeCr alloy into the molten pig iron and melting the alloy into the molten pig iron to prepare a molten composition expressed by the following general formula: Fe.sub.C.sub.Si.sub.B.sub.xP.sub.yCr.sub.z, where , , , x, y and z are respective atomic % of iron (Fe), carbon (C), silicon (Si), boron (B), phosphorus (P) and chromium (Cr), wherein a is expressed by =100(++x+y+z) atomic %, is expressed by 13.5 atomic %17.8 atomic %, is expressed by 0.30 atomic %1.50 atomic %, x is expressed by 0.1 atomic %x4.0 atomic %, y is expressed by 0.8 atomic %y7.7 atomic % and z is expressed by 0.1 atomic %z3.0 atomic %; and rapidly quenching the molten composition to form the iron-based amorphous alloy.

2. The method of manufacturing a high carbon iron-based amorphous alloy of claim 1, wherein: the molten pig iron contains iron (Fe) of 80.4 atomic %Fe85.1 atomic %, carbon (C) of 13.5 atomic %C17.8 atomic %, silicon (Si) of 0.3 atomic %Si1.5 atomic %, phosphorus (P) of 0.2 atomic %P0.3 atomic %.

3. The method of manufacturing a high carbon iron-based amorphous alloy of claim 1 further comprising melting the alloy after quenching and again rapidly quenching into an amorphous alloy.

4. The method of manufacturing a high carbon iron-based amorphous alloy of claim 2, wherein: the rapidly quenching is carried out by one of rapidly quenching a mold directly, a melt spinning, and an atomizing method.

5. The method of manufacturing a high carbon iron-based amorphous alloy of claim 1, wherein: the high carbon iron-based amorphous alloy is any one of a ribbon shape, bulk, and powder.

6. The method of manufacturing a high carbon iron-based amorphous alloy of claim 2, wherein: the high carbon iron-based amorphous alloy is any one of a ribbon shape, bulk, and powder.

7. The method of manufacturing a high carbon iron-based amorphous alloy of claim 3, wherein: the high carbon iron-based amorphous alloy is any one of a ribbon shape, bulk, and powder.

8. The method of manufacturing a high carbon iron-based amorphous alloy of claim 4, wherein: the high carbon iron-based amorphous alloy is any one of a ribbon shape, bulk, and powder.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a graph illustrating results of X-ray diffraction of a high carbon iron-based amorphous alloy manufactured according to a first exemplary embodiment of the present invention;

(2) FIG. 2 is a graph illustrating results of X-ray diffraction of a high carbon iron-based amorphous alloy manufactured according to a second exemplary embodiment of the present invention;

(3) FIG. 3 is a graph illustrating results of X-ray diffraction of a high carbon iron-based amorphous alloy manufactured according to a third exemplary embodiment of the present invention;

(4) FIG. 4 is a graph illustrating results of X-ray diffraction of a high carbon iron-based amorphous alloy manufactured according to a fourth exemplary embodiment of the present invention;

(5) FIG. 5 is a graph illustrating results of X-ray diffraction of a high carbon iron-based amorphous alloy manufactured according to a fifth exemplary embodiment of the present invention;

(6) FIG. 6 is a graph illustrating results of X-ray diffraction of a high carbon iron-based amorphous alloy manufactured according to a sixth exemplary embodiment of the present invention;

(7) FIG. 7 is a graph illustrating results of X-ray diffraction of a high carbon iron-based amorphous alloy manufactured according to a seventh exemplary embodiment of the present invention;

(8) FIG. 8 is a graph illustrating results of X-ray diffraction of a high carbon iron-based amorphous alloy manufactured according to an eighth exemplary embodiment of the present invention;

(9) FIG. 9 is a graph illustrating results of X-ray diffraction of a high carbon iron-based amorphous alloy manufactured according to a first comparative example of the present invention; and

(10) FIG. 10 is a graph illustrating results of X-ray diffraction of a high carbon iron-based amorphous alloy manufactured according to a second comparative example of the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

(11) The terms used in the following description are not intended to limit the present invention, but, are merely used to describe the specific exemplary embodiment(s) of the invention. It is to be understood that the singular forms include plural referents unless the context clearly dictates otherwise. The terms comprising, having, including, and containing used herein are to define a specific feature, region, integer, steps, operations, elements and/or components, but does not exclude presence and addition of other features, regions, integers, steps, operations, elements, components, and/or groups.

(12) Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Unless defined otherwise, the terms defined in usual dictionaries have the same meaning used in related technical documents and herein but are not understood as ideal meanings and very official meanings.

(13) Hereinafter, exemplary embodiments according to the present invention will be described in detail. The exemplary embodiments according to the invention are provided for the purpose of explaining the principles of the invention but do not limit the present invention.

(14) An iron-based amorphous alloy composite according to an exemplary embodiment of the present invention is expressed by a general chemical formula Fe.sub.C.sub.Si.sub.B.sub.xP.sub.yCr.sub.z, where , , , x, y and z indicate atomic % of iron (Fe), carbon (C), silicon (Si), boron (B), phosphorus (P) and chrome (Cr) respectively, and preferably is expressed by =100(++x+y+z) atomic %, is expressed by 13.5 atomic %17.8 atomic %, is expressed by 0.30 atomic %1.50 atomic %, x is expressed by 0.1 atomic %x4.0 atomic %, y is expressed by 0.8 atomic %y7.7 atomic %, and z is expressed by 0.1 atomic %z3.0 atomic %.

(15) Hereinafter, the reason for restricting atomic % of each component of the amorphous alloy according to an exemplary embodiment of the present invention will described.

(16) First, carbon (C) and silicon (Si) are preferably 13.5 atomic % to 17.8 atomic % and 0.30 atomic % to 1.50 atomic % respectively. As such, the reason of restricting carbon (C) and silicon (Si) is to utilize molten pig iron produced at an integrated steel mill during the iron making process as it is in the exemplary embodiment of the present invention.

(17) The molten pig iron mass-produced by a blast furnace at an integrated steel mill consists of iron (Fe), carbon (C), silicon (Si), and phosphorus (P) and concentrations of the respective components are as follows. That is, iron (Fe) is contained by 80.4 atomic %Fe85.1 atomic %, carbon (C) is 13.5 atomic %C17.8 atomic %, silicon (Si) is 0.3 atomic %Si1.5 atomic %, phosphorus (P) is 0.2 atomic %P0.3 atomic %.

(18) Therefore, in an exemplary embodiment of the present invention, as much as possible of the molten pig iron as a main raw material of the iron-based amorphous alloy can be used.

(19) Next, phosphorus (P) will be described. Since phosphorus (P) is contained in the molten pig iron produced by the blast furnace by a low concentration, phosphorus (P) is hard to be formed as amorphous during the quenching. Therefore, in order for phosphorus (P) to be amorphous, more predetermined concentration of the phosphorus (P) should be controlled. However, when phosphorus (P) is added too much, manufacturing costs of the amorphous alloy increase. Therefore, concentration of phosphorus (P) is preferably controlled by 0.8 atomic % to 7.7 atomic % so as to maintain excellent glass forming ability even at minimum threshold concentration and to form amorphousness.

(20) Next, boron (B) will be described. Boron (B) is controlled by an amount needed to form amorphousness in an iron-based alloy but excessive amount of boron (B) brings increase of manufacturing costs of an amorphous alloy. Therefore, concentration of boron (B) is preferably controlled by 0.1 atomic % to 4.0 atomic % with minimum threshold concentration so as to maintain excellent glass forming ability and to form amorphousness.

(21) Next, chrome (Cr) will be described. Concentration of chrome (Cr) is preferably controlled by 0.1 atomic % to 3.0 atomic % so as to form amorphousness and particularly to improve corrosion resistance. In order to form amorphousness and to improve corrosion resistance, concentration of chrome (Cr) is controlled to as much as possible up to an upper limit 3 atomic %. The reason of restricting limiting the upper limit of the concentration of chrome (Cr) is because chrome (Cr) is added in the form of FeCr alloy iron which is expensive and has high melting point so that a large amount of energy is needed and this is disadvantageous in economical view.

(22) Hereinafter, a method of manufacturing an iron-based amorphous alloy according to an exemplary embodiment of the present invention will be described.

(23) The iron-based amorphous alloy according to an exemplary embodiment of the present invention is manufactured by utilizing molten pig iron produced by a blast furnace as a base alloy.

(24) First, the molten pig iron produced by a blast furnace of a steel mill is received in a torpedo car or a ladle and is added with an alloy iron to have a composition proper to produce an iron-based amorphous alloy.

(25) The prepared molten pig iron preferably contains iron (Fe) of 80.4 atomic %Fe85.1 atomic %, carbon (C) of 13.5 atomic %C17.8 atomic %, silicon (Si) of 0.3 atomic %Si1.5 atomic %, and phosphorus (P) of 0.2 atomic %P0.3 atomic %.

(26) In order for the prepared molten pig iron to have the composition of the amorphous alloy according to an exemplary embodiment of the present invention, silicon (Si) is added with FeSi alloy, boron (B) is added with FeB alloy, phosphorus (P) is added with FeP alloy, and chrome (Cr) is added with FeCr alloy by weighing. In this case, boron (B) of the added FeB alloy and phosphorus (P) of the added FeB alloy decrease melting temperature of the molten pig iron and delay crystallization during the quenching to improve glass forming ability. Moreover, chrome (Cr) of the added FeCr alloy improves the produced corrosion resistance of amorphous alloy.

(27) The respective alloy irons added into the molten pig iron are melted by sensible heat. The molten pig iron added with alloy irons may be inserted into a tundish and may be injected with gas such as pure oxide, oxide mixture, air or solid oxide such as iron oxide and manganese oxide.

(28) Moreover, in order to control temperature of the molten pig iron in the tundish, temperature of molten metal is optimized using a temperature increasing device provided in the tundish. If necessary, an inert gas such as nitride or argon gas provided in the lower side of the tundish may be injected to generate bubbling and to improve melting and alloying efficiency of the alloy iron. The molten metal prepared as described above may be used as liquid or may be quenched in a mold and may be melted in a crucible again.

(29) Next, a method of manufacturing an amorphous alloy will be described with an example of manufacturing of an amorphous alloy using the molten metal as liquid is.

(30) When an amorphous alloy is manufactured in bulk, molten metal is poured into a mold and is rapidly quenched at quenching rate of at least 100 C./sec. Moreover, when an amorphous alloy is manufactured in the form of a ribbon, prepared molten metal is fed onto a surface of a single role or surfaces of twin roles rotating at high speed using a melt spinning apparatus and is rapidly quenched at least quenching rate of 100 C./sec. Here, the well-known melt spinning apparatus may be used and its description will be omitted.

(31) As described above, an amorphous alloy according to an exemplary embodiment of the present invention may be manufactured in an amorphous alloy ribbon by a rapid quenching such as melt spinning, in bulk by the rapid quenching, or in powder by atomizing. If amorphous powder is manufactured by atomizing, firstly powder may be manufactured, preforms may be fabricated using the powder, and the preforms may be applied with high pressure at high temperature to be formed into amorphous parts in bulk while maintaining amorphous structure.

(32) Hereinafter, the present invention will be described in more detail by an experimental example. The experimental example is provided only to illustrate the present invention but the present invention is not limited thereto.

Experimental Example

(33) First, high carbon molten pig iron produced by a blast furnace at an integrated steel mill is injected into a ladle. Next, FeP alloy iron, FeB alloy iron, FeSi alloy iron, and FeCr alloy iron are added into the ladle. In this case, the respective added alloy irons are melted by sensible heat of the molten pig iron.

(34) Then, loss of oxidation of alloys is minimized by carbon in the molten pig iron. Next, the molten pig iron in the ladle is injected in to the tundish and oxide iron and manganese oxide are poured while taking oxide mixture to control concentration of carbon.

(35) The temperature-increasing apparatus is driven to assist melting of the alloy iron and to optimize temperature of the molten metal and argon gas is taken from the lower side of the tundish to generate bubbling. Composition of the molten pig iron prepared as described above is as listed in Table 1.

(36) Next, the prepared molten pig iron is injected into a crucible provided in the melt spinning apparatus and the molten pig iron in the crucible is fed onto the surface of a single role of the melt spinning apparatus rotating at high speed. The molten pig iron fed onto the surface of the single role is rapidly quenched and is manufactured into a ribbon specimen with a width about 0.5-1.3 mm and thickness of 20-35 mm.

(37) At this time, the quenching conditions in the first to eighth exemplary embodiments and the comparative examples 1 and 2 are identical to each other.

(38) Crystallization of the specimens fabricated as described above is measured by an X-ray diffractometer. The results of the X-ray diffraction of the alloys manufactured to have compositions as described in the measured first to eighth exemplary embodiments and the comparative examples 1 and 2 are illustrated in FIGS. 1 to 10.

(39) TABLE-US-00001 TABLE 1 Composition formula (atomic %) Amorphous? exemplary Fe.sub.78.8C.sub.14.0Si.sub.1.4B.sub.2.2P.sub.1.5Cr.sub.2.1 embodiment 1 exemplary Fe.sub.75.3C.sub.13.8Si.sub.0.7B.sub.0.4P.sub.7.7Cr.sub.2.1 embodiment 2 exemplary Fe.sub.75.1C.sub.13.6Si.sub.1.3B.sub.2.2P.sub.7.5Cr.sub.0.3 embodiment 3 exemplary Fe.sub.75.3C.sub.13.8Si.sub.0.7B.sub.0.4P.sub.7.7Cr.sub.2.1 embodiment 4 exemplary Fe.sub.76.0C.sub.14.4Si.sub.1.4B.sub.0.4P.sub.7.5Cr.sub.0.3 embodiment 5 exemplary Fe.sub.78.0C.sub.16.2Si.sub.1.3B.sub.0.4P.sub.3.8Cr.sub.0.3 embodiment 6 exemplary Fe.sub.79.2C.sub.17.3Si.sub.1.3B.sub.0.4P.sub.1.5Cr.sub.0.3 embodiment 7 exemplary Fe.sub.79.6C.sub.17.6Si.sub.1.3B.sub.0.4P.sub.0.8Cr.sub.0.3 embodiment 8 Comparative Fe.sub.82.5C.sub.13.1Si.sub.2.0B.sub.0.6P.sub.1.5Cr.sub.0.3 X Example 1 Comparative Fe.sub.84.6C.sub.12.4Si.sub.0.7B.sub.0.4P.sub.1.6Cr.sub.0.3 X Example 2

(40) As illustrated in FIGS. 1 to 8, it is understood that, as a result of the X-ray diffraction for FeCSiPBCr-based (iron-based), alloy manufactured with composition according to the first to eighth exemplary embodiments, none of diffraction peak is observed but only broad halo pattern near a diffraction angle as two theta of 42 degrees is observed. From the results of X-ray diffraction, it is understood that all alloys manufactured with the compositions as described in the first to eighth exemplary embodiments have an amorphous structure.

(41) However, as seen from FIGS. 9 and 10, from the results of X-ray diffraction for FeCSiPBCr-based alloys manufactured with the compositions as described in the comparative examples 1 and 2, a diffraction peak of crystals is observed from crystals so that the alloys have a crystalline structure. These results are because carbon (C) and silicon (Si) are controlled under a range lower than an optimized range as described in the present invention and do not meet the threshold concentration for forming amorphousness.

(42) Moreover, according to the first to eighth exemplary embodiments, the manufactured alloys can maintain the amorphousness even when the added amount of boron (B) is small within 0.1 to 4.0 atomic % and the manufactured alloys have amorphousness even when phosphorus (P) of a relative low range 0.8 to 7.7 atomic % is added.

(43) While this invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.