JPH03223414A - Production of iron-nickel-cobalt-base alloy minimal in respective contents of sulfur, oxygen, and nitrogen - Google Patents

Abstract

PURPOSE:To produce an Fe-Ni-Co-base alloy with very low S, O, and N contents by subjecting a molten Fe-Ni-Co alloy to deoxidation, desulfurization, and denitriding by the use of Al, Ti, etc., in a vessel composed of a refractory containing MgO and CaO. CONSTITUTION:A molten alloy composed essentially of Fe, Ni, and Co is charged to a vessel, such as crucible, composed of a basic refractory containing, by weight, 15-75% MgO and 15-85% CaO. Subsequently, a first additive agent consisting of Al or Al alloy, a second additive agent consisting of Ti, Zr, Nb, or rare earth element, and further, if necessary, <=5% flux containing the oxides, halides, silicates, and carbonates of alkali metals and alkaline earth metals, Al oxide, etc., are added to the above alloy. Then, this molten alloy is subjected to deoxidation, desulfurization, and denitriding under a nonoxidizing atmosphere or in vacuum, by which the molten alloy containing 0.005-7.0% residual Al, 0.0001-0.005% residual Ca, and 0.0001-0.03% residual Mg is obtained. This molten alloy is ingoted, by which the Fe-Ni-Co-base alloy having extremely reduced O, S, and N contents as low as <=0.003%, <=0.010%, and <=0.03%, respectively, can be obtained.

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a method for producing a high purity iron-, cobalt-1 or nickel-based alloy, more particularly comprising iron (Fe), cobalt (cO) and nickel (Ni). The present invention relates to a method for producing an alloy containing at least one main component selected from the group consisting of at least one main component selected from the group, and having extremely low sulfur, oxygen, and nitrogen contents. (Prior art) As is already known, iron-based alloys, cobalt-based alloys,
Many nickel-based alloys have excellent mechanical properties, heat resistance, and corrosion resistance. However, if the residual oxygen and residual sulfur are large, the processability will deteriorate, so it is important to sufficiently reduce the residual oxygen and residual sulfur. It is generally known that CaO-based refractories are stable even at high temperatures and are used for melting various highly reactive alloys. It is also known that when aluminum or aluminum alloy is added to the molten metal in a container lined with this CaO-based refractory, CaO is reduced by A1 to produce Ca, and deoxidation and desulfurization reactions proceed. . That is, Tokuko Sho 54 (1979)-849, Tokuko Sho 54 (1979)-24688, and Tokko Tokko Sho 60 (1979)
985)-25486, a melting furnace supported by a highly basic refractory with a CaO content of 40% or more,
A method for deoxidizing and desulfurizing molten steel is described in which a lime crucible or a lime-lined ladle is used to add AI or its alloy to molten steel in a vacuum or an argon gas atmosphere. The gist of this method is to reduce CaO in the refractory by adding AI, and remove sulfur and oxygen in the molten steel using Ca, which is a reduction product. Furthermore, U.S. Pat. No. 4,484,946 discloses that when the basic refractory-backed melting furnace or crucible is repeatedly used in the method, calcium oxysulfide is deposited on the wall of the melting furnace or crucible. accumulates and reduces the rate of deoxidation and desulfurization, therefore flux is added to the molten steel together with additives such as AI, thereby preventing the accumulation of said compounds on the walls of the lime crucible melting furnace or lime crucible. It is stated that (Problems to be Solved by the Invention) According to the above-mentioned conventional method, the sulfur content of molten steel is reduced to approximately 0.00%.
4% by weight, oxygen can be reduced to 0.002% by weight. However, in the field of alloy refining, there is a desire for a refining technology with higher desulfurization and deoxidizing abilities. (Means for Solving the Problems) The object of the present invention is to solve the problems by:
It is an object of the present invention to provide an improved method for producing iron-, cobalt-1 or nickel-based alloys which have lower sulfur, oxygen and nitrogen contents. To achieve this objective, the present invention comprises a basic refractory comprising 15-75% by weight of MgO and 15-85% by weight of CaO, or supported by said refractory.
Crucible, crucible furnace, melting furnace, refining furnace (VOD, , AOD),
melting an alloy substantially consisting of at least one main component selected from the group consisting of Fe, Co, and Ni in any one container selected from the group consisting of a converter or a ladle; A first additive selected from aluminum or an aluminum alloy and titanium, zirconium,
a second selected from the group consisting of niobium and rare earth elements;
a step of deoxidizing, desulfurizing and denitrifying by adding a third additive selected from boron, alkali metals and alkaline earth metals and flux as necessary;
and forming an agglomerate from the molten alloy that has been deoxidized, desulfurized, and denitrified in this way.
An object of the present invention is to provide a method for producing a base alloy. The flux added to the above-mentioned additives may contain at least one component selected from the group consisting of oxides, halides, carbides, and carbonates of alkali metals and alkaline earth metals, and oxides of aluminum. shall be selected. In a preferred embodiment, the vessel is a crucible, crucible furnace, refining furnace, VOD (vacuum oxydiene degasser), AOD (air oxydiene degasser), converter or ladle. The same (the non-oxidizing atmosphere is an atmosphere of argon gas, nitrogen gas, or helium gas). 15-85% by weight
of CaO, preferably 40 to 70% by weight. The above additives are AI! -Ca clad wire, AA-8
The desulfurization efficiency is further promoted by using an A1-based composite additive such as i-clad wire (a clad material in which the additive is charged as a powder into an aluminum or iron sheath and then pressure-drawn into a wire). Flux can be added to the above additives in combination, if necessary. As this fluff component, a flux consisting of at least one member selected from the group consisting of alkali, alkaline earth metal oxides, silicides, carbonates, and halides, or a combination of this and aluminum oxide can be used. Similarly, the iron-, cobalt-1 and nickel-based alloys produced contain less than 0.002% by weight of residual sulfur, less than 0.002% by weight of residual oxygen, and less than 0.003% by weight of residual nitrogen. Similarly, the iron-, cobalt-1 and nickel-based alloys are
After deoxidizing, desulfurizing, and denitrifying the molten alloy, the final molten metal contains 0.005 to 7% by weight of residual AI, 0.0001 to 0.00% by weight.
005% by weight of residual Mg and 0.0001 to 0.005
It is necessary to contain % by weight of residual Ca. Similarly, the iron-, cobalt-1 and nickel-based alloys further include titanium (Ti), zirconium (Zr).
, niobium (Nb) and rare earth elements and boron (B)
, alkali metals, and alkaline earth metals excluding Mg and Ca. The above-mentioned Japanese Unexamined Patent Publication No. 1979-58010 describes a process of melting steel in a melting furnace or ladle supported by a basic refractory containing at least 60% by weight of CaO, and a process for melting the molten steel. By adding Al2 under an argon gas atmosphere or vacuum, the backing reduces CaO in the refractory to generate Ca, which deoxidizes, desulfurizes, and denitrates the molten steel, and also deoxidizes the molten steel. 0 Al7 inside
．． 005-0.06% by weight, Ca 0.001-0.0
3% by weight, oxygen content is 0.003% by weight or less, sulfur content is 0.010% by weight or less, and nitrogen content is 0.003% by weight or less.
0.010% by weight or less, oxygen;
A method for producing clean steel with low sulfur and nitrogen contents is described. However, the inventors further experimented with the above method and found that
After repeated studies, we found that in the furnace wall of a crucible or ladle where MgO and CaO coexist, when AI or A1 alloy is added, Mg is also produced in addition to Ca in the molten steel, resulting in a strong deoxidation layer. It has been found that desulfurization occurs. The present invention is based on this finding. In one embodiment of the invention, a vessel such as a crucible, crucible furnace, or converter, ladle made of a basic refractory containing 15-75% by weight MgO and 15-85% by weight CaO is used. , an iron-based alloy, a cobalt-based alloy, or a nickel-based alloy is melted in this container. At least one of AI and A1 alloy is added to the molten alloy in the vessel under a non-oxidizing atmosphere such as argon, nitrogen, or helium gas or under vacuum. In another embodiment, the alloy is previously melted in a commonly used furnace and the molten alloy is charged into the vessel. Aluminum or aluminum alloy is similarly added to the molten alloy in this container. In another embodiment, the vessel is replaced by a vessel, such as a crucible furnace, converter or ladle, backed by the refractory. In each of the above embodiments, aluminum (A7) in the additive added to the molten alloy in the container is partially combined with oxygen in the molten alloy under vacuum or a non-oxidizing atmosphere to form A12os. is generated and deoxidized, but the other part of Al reacts with MgO and CaO on the surface of the refractory in a vacuum or non-oxidizing atmosphere to form 3 Ca O+ 2 A 1=3 Ca + Al2O3
---(1)3MgO+2,12→3Mg+Al
2O3...(2), and Mg, Ca and Al2O3 are generated. In particular, the reaction (2) is carried out in vacuum or in a non-oxidizing atmosphere with CaO
The presence of an appropriate amount (15-85%) facilitates progression to the right side. This reaction is considered to be a complex reaction as shown below. 3 Mg O+Ca O+2 A f→3 Mg O+
CaAl20< −・−(3) This CaO・Al2O3
Calcium aluminate, which is mainly composed of , has a high desulfurization ability and desulfurization of the molten alloy progresses. Also, the following reaction occurs due to the presence of Ti, Ce, etc.CaO content -+Ca+TiO...
・・・・・・・・・(4) MgO+Ti→Mg+TiO・・
・・・・・・・・・・・・・・・・・・(5)3CaO+2
Ce→3Ca+CezOa = (6)3 MgO+2
Ce-”3 Mg×Ce 203-=・(7) In addition to the above reaction, oxygen, sulfur, and nitrogen in the molten metal are added Al7
．． First, 2Al+30→A120a・・・・・・・・・・・・・・・・Ti, Zr, NbXCe etc.
・・・・・・(8) AIten-AIN ・・・・・・
・・・・・・・・・・・・(9)T i +O−*T
i O・・・・・・・・・・・・・・・・・・00)T
i 1N-+T i N ・・・・・・・・・・・・
・・・・・・・・・(11) Ti+S−+TiS
・・・・・・・・・・・・・・・((2)2 Ce +
30→Ce 203-・--・(13)2 Ce
+38-4-Ce zs 3---・”-(14)Ce
+N-+CeN・・・・・・・・・・・・・・・
...(19Z r + 20-+Z r O2...
・・・・・・・・・・・・・・・・・・(16) Zr+2S
-*Zr5z・・・・・・・・・・・・・・・・・・(
17) Zr+N→ZrN ・・・・・・・・・・・・
・・・・・・・・・(1 second 2 N b + 50=N b
206 ・・・・・・・・・・・・(19) Nb+N
-+NbN ・・・・・・・・・・・・・・・・・・
...■2 N b + 5 S + N b 2 S
s ・・・・・・・・・・・・・・・(21) In addition, the sulfur, oxygen, and nitrogen components remaining in the molten metal are determined by the following formulas, respectively, due to Mg and Ca reduced and precipitated in the molten metal as described above. An extremely clean molten metal is obtained. Ca+S-+CaS・・・・・・・・・・・・・・・
・・・・・・(22)Ca+0→CaO・・・・・・・・・
・・・・・・・・・・・・(23)3 Ca + 2
N=Ca! N 2 ・−・・・”・(24) Mg
10S→MgS・・・・・・・・・・・・・・・・・・
・(25) Mg+0-MgO・・・・・・・・・・・・
・・・・・・(26) 3Mg+2N→M g a N
2・・・・・・・・・・・・(27) In this way, Al
2 deoxidizes the molten metal, and further deoxidizes and desulfurizes the active Mg and Ca produced by the reducing action of AI and calcium aluminate (3CaO.Al203). These reactions proceed extremely rapidly, so after adding 17 to the molten metal, desulfurization and
Deoxidation is almost completed. Further, as time passes, the amount of N in the molten metal gradually decreases. This is because N also leaves the molten metal as Ca, Mg, etc. evaporate (boil). This denitrification rate increases significantly as deoxidation and desulfurization progress under non-oxidizing gas (for example, argon gas atmosphere) or vacuum. In the present invention, a container such as a converter, a melting furnace, a crucible, or a ladle has Mg015-75% by weight and CaO15-15% by weight.
The reason why the refractory is composed of or supported by a composition containing 85% by weight will be explained. Figures 1 and 2 show M in CaO-MgO refractory materials.
The desulfurization characteristics are shown in experiments in which crucibles with various gO contents were used and 0.5% Al was added to the molten metal to the molten iron. 10g [S]t / [S]o in Fig. 2 is the desulfurization capacity, [S)t is the amount of residual sulfur after t minutes, and (S)
) o indicates the initial sulfur amount. As shown in the figure, MgO is 15
It is clearly seen that when the content is between 70% and 20% and 60%, a very strong desulfurization reaction takes place. Fig. 2 also shows the analytical value of residual AI (A47% by weight), and it was observed that the amount of Al decreased with the passage of time after addition, and this caused the aforementioned reaction between MgO and AI. Progress is confirmed. CaO is essential as the remaining component other than MgO. CaO is itself reduced by 1 to produce Ca, and also promotes the reduction reaction of MgO by coexisting with MgO. A preferable content of CaO is at least 1% of the entire refractory.
5% or more, especially 40 to 80% by weight. When the CaO content is lower than 40%, C in the refractory
Since aO is strongly bonded to other oxides, CaO has little activity and is difficult to be reduced by Al2. In contrast, CaO in refractories with at least 40% CaO
has high activity and is easily reduced by Af. In addition, refractories containing at least 40% CaO are Al2
It easily reacts with oxides such as O3 and 5iOz, and therefore absorbs oxides in the molten metal, greatly reducing the amount of oxide inclusions. Moreover, such refractories include C and Ti. Since it has high stability against Zr and the like, it is possible to melt the alloy at high temperatures. In addition, when adding at least one member selected from the group consisting of metallic calcium or calcium alloy, alkali metals, and alkaline earth metals to aluminum as an additive,
When CaO in the refractory is 40% by weight, at least the activity of CaO in the refractory becomes large (Aj7+Ca) or (AA
+ (Na, K. Li)), the deoxidation and desulfurization rates are increased. In carrying out the present invention, Ti, Zr,
A second additive consisting of Nb and a rare earth element (such as CE) and at least one third additive selected from the group consisting of B, an alkali metal, and an alkaline earth metal may be added. Examples of the alkali metal include Na, and Li. For example, Ca, B, Na* added to the molten metal,
Li is CaO, B2O3, Na2O, k20,
Lt20, and in the refractory wall, these oxides are Al2O3-Ca 0-B203 A1203 Ca OB2O3Na20A1203
Forming a low melting point composition such as Ca OB2O3k20,
It can increase deoxidation and desulfurization rates and prevent contamination of large objects on the furnace wall. That is, oxides such as Ca, B, Na, K, and Li combine with the calcium aluminate composition such as CaO.MgO already formed on the furnace wall surface to produce a low melting point composition. In this composition, the compounds, atoms or ions thereof (eg B2-, etc.) in the molten alloy readily diffuse, thus accelerating the deoxidation and desulfurization reactions. Also oxides of CaO, B2O3 and alkali metals, especially B20. and alkali metal oxides, when incorporated into the slag, also lower the melting point of the slag and lower its viscosity. This increases the diffusion coefficient of ions such as 82-, other atoms, and compounds in the molten alloy to the slag. Therefore, the desulfurization rate increases,
The deoxidizing ability is greatly improved. In the practice of the present invention, residual aluminum o, oos ~ 7% by weight residual magnesium o, oooi ~ 0.005% by weight in the produced Fe-Co- or Ni-based alloy.
It is necessary to add these metals in such a way that in each case 0.0001 to 0.005% by weight of residual calcium remains. The reason why the residual amount of AI in the alloy is preferably in the range of 0.005 to 7% by weight is that when the residual amount of AI is less than 0.005%, not only is sufficient deoxidation not performed;
Almost no Ca is generated. Therefore, almost no desulfurization, deoxidation, and denitrification by Ca is achieved, and the amount of residual calcium in the finished alloy is at least 0, which is the basis for sufficient desulfurization, deoxidation, and denitrification by Ca. This is because it does not reach .0001%. On the other hand, the upper limit is because alloys containing more than 7% aluminum are impractical. If the B residual amount is less than 0.001%, it is too small and the effect of B is small, and if it is more than 10%, the manufactured alloy becomes brittle. A particularly preferable residual amount of B is 0.005 to 3%. Aluminum (An) and titanium, zirconium,
When boron (B), alkali metals, and alkaline earth metals are added to the molten metal in addition to niobium and rare earth elements, they may be added in the form of alloys or as single metals; There are no particular restrictions on the form. When adding aluminum (Af), Ti, Zr, Nb, rare earth elements, and boron (B), it is possible to add these as single metals, but alkali metals and alkaline earth metals do not react. It is preferable to add it in the form of an alloy because it has high properties and has problems in handling. Regardless of whether it is added as a single metal or an alloy together with An, it can be added in various forms such as a linear body, a rod-shaped body, a block, a powder, or a clad wire. -For example, Al
-Ca clad wire or an Af-Ca clad wire obtained by adding flux to an Al-Ca core material can be used. The residual amounts of Mg and Ca in the alloy produced by the method of the present invention are M g 300~l ppm (0,03~0
．． 0001% by weight), preferably 30-5 ppm
(0,003~0.0005% by weight), Ca200~
1 ppm (0.02-0.0001% by weight), preferably 100-5 ppm (0.01-0.000
5% by weight) is appropriate. Mg residual amount and Ca
If the residual amount is too small, the deoxidizing, desulfurizing, and denitrifying effects will be low, and if the residual amount is too large, the alloy will become brittle. In addition, in the present invention, rare earth elements are further added to the molten metal.
It may be added so that it remains in the final product alloy in a range of 200 ppm or less. In a preferred embodiment of the present invention, oxides, carbonates, decogenides of alkali metals and alkaline earth metals,
This effect is effective when continuously refining by repeatedly adding 5% or less of flux containing a small amount of carbides and alumina, etc. To prevent this, the contaminants can be removed by using a flux.The present invention will be explained in more detail with reference to the following specific examples.Comparative Example 1 Composition shown in Table 1 500 g of electrolytic iron having the composition shown in Table 2 to which FeS had been added in advance to give a sulfur content of about 0.03% was charged as a starting material into a CaO crucible, and the crucible was subjected to high frequency melting at 50 KHz. The material was placed in a furnace and melted. After melting, 0.4% (weight) of A1 alloy was added to the molten material while introducing argon gas into the furnace. After the addition, the molten material was added at predetermined intervals. The sample was collected by suction and its oxygen, sulfur, and nitrogen contents were measured.The deoxidizing ability log [0] o / [0] t
([0]t is the amount of residual oxygen after t minutes,

[0]o indicates the initial oxygen amount. ) Figure 3 shows the changes over time in the desulfurization capacity fog[s)/[S]o and the nitrogen content. The CaO crucible used was made from CaO, a -grade reagent, which was crushed into 20 meshes, put into a crucible mold, and solidified. It was produced by calcining in a resistance furnace. Table 1 Crucible composition Table 2 Electrolytic iron composition Example 1 A MgO-CaO crucible with the composition shown in Table 3 was prepared using first-class reagents MgO and CaO as raw materials, and comparison was made using this. The experiment was conducted according to the same procedure as in Example 1. The results are also shown in FIG. Composition with crucible in Table 3 As is clear from FIG. 3, according to the method of the present invention, a molten metal with low oxygen, sulfur and nitrogen contents can be quickly obtained, and it is recognized that the desulfurization effect is particularly large. The CaO-MgO crucible used in the above test was made using pure materials with few impurities, but
When a CaO-enriched dolomite brick made by enriching a dolomite brick containing 2.4% CaO was used, the desulfurization effect was significantly reduced. The reason for this is that Sing contained as an impurity is Cab,
This is thought to be because Ca and Mg were not generated when Ajl' was added to molten steel because it was stabilized by combining with MgO. Example 2 The amount of AI added was 0.5% by weight of the molten metal, and the M of the crucible material was
An experiment was conducted in the same manner as Comparative Example 1, except that the gO content was variously changed from 10% to 70%. Figures 1 and 2 show the results of measuring desulfurization properties and A1 residual amounts for samples using crucibles of different compositions. Incidentally, FIG. 2 also shows the measurement results in Comparative Example 1 (using a crucible containing 100% caO). From these figures 1 and 2, as mentioned above, MgO15
70% and CaO of 15 to 85%, it is recognized that a remarkable desulfurization effect can be obtained. As described above, the alloy produced by the method of the present invention has a sulfur content of 1/50 or less (15 ppm or less, particularly 10 ppm or less) and an oxygen content of 1/50 or less (7 ppm or less) of the initial content.
(Below) It can be seen that this is an extremely clean alloy with a nitrogen content of 30 ppm or less, especially 20 ppm or less. As described above, according to the present invention, Fe group, Co group and Ni
Extremely strong deoxidation, desulfurization, and denitrification can be performed in the production of base alloys, resulting in extremely low O, S, and N content, and excellent properties such as creep strength, heat resistance, toughness, weldability, and forgeability. It is possible to produce alloys with significantly superior properties. Furthermore, according to the method of the present invention, a product with almost no oxide inclusions can be obtained. In the detailed description of the present invention, "non-oxidizing gas" means
Argon gas, nitrogen gas,
or by treating the molten metal by blowing in a non-oxidizing gas such as helium gas, or by forming an atmosphere of this gas on the surface of the molten metal so that the surface of the molten metal in a closed furnace is covered with such gas, This refers to the atmosphere in which molten metal is processed. As mentioned above, the alloy targeted by the method of the present invention is Fe-based,
It is a Co-based and Ni-based alloy. Common elements C and Si are used as Fe-based alloys. Carbon steel containing Mn, P, and S and 2% or less of C, and Ni and C in addition to the above ordinary elements to give special properties.
In addition to special elements such as r, Co, W, Mo, Af, and Ti, there are alloy steels that exceed the content range of ordinary elements and are added for the purpose of adding special properties, even if they belong to ordinary elements. Representative. Low-alloy steels include high-strength low-alloy steel, high-temperature, high-pressure low-alloy steel, and low-alloy steel for the petroleum industry. High-alloy steels include chromium steel and nickel steel, and high-alloy steels include high-chromium stainless steel. , high chromium-nickel stainless steel, etc. Nickel-based alloys contain nickel as a main component, and include heat-resistant and corrosion-resistant alloys, magnetic alloys, and the like. Alloys belonging to this include Ni
-Cu alloy (Monel metal) Ni-Cr-Fe alloy (
Inconel), NiMo alloys (Hastelloy A, B)
, Ni-Mo-Cr-W alloy (Hastelloy C)
, Ni-8i alloy (Hastelloy D), Ni-Ta alloy, etc. Examples of Co-based alloys include those containing CO as a main constituent, such as heat-resistant alloys, corrosion-resistant alloys, ultra-high alloys, and magnetic alloys. Alloys belonging to this category include Co-Cr-W-
C-based alloy (stellite), Co-Fe-based alloy (duct
ile cobalto gold), c. -Cr-Ni-Mo alloy (Etigi Iy), Co
-Cr-N1-W alloy (Hayness), Vica
lloy. Examples include Co alloys for magnetic materials such as Renendur and Permendur, and Co-based super superalloys that utilize precipitation of Ni and Ti. Examples 3 to 8 A fourth
300 ppm (0,0
500g of FeS was added in advance to give a sulfur content of 3%) as a starting material, and this crucible was heated to 50K.
The material was melted in a high frequency melting furnace at Hz. After melting, 0.5% by weight of A1 alloy was added to the molten alloy without introducing argon gas into the furnace. After the addition, samples were taken from the molten alloy by suction at predetermined intervals, and the amounts of oxygen, sulfur, and nitrogen were measured. The deoxidizing capacity log (Olt/

[0]o (where [O]t indicates the amount of residual oxygen after t minutes, [0)o indicates the initial amount of oxygen), desulfurization capacity log (S) t / [S] o
% and nitrogen content over time are shown in Figure 4. In Figure 4, 0.5% AI was added, [SO3 was 10% Mg0, 30% Mg in a CaO crucible with an initial sulfur content of 300 ppm.
An example using a CaO-MgO crucible to which g0,50% MgO160% Mg0,70% MgO is added is shown. The CaO-MgO crucible used was a general reagent C.
Using aO, MgO as raw materials, crush this into 20 meshes, put it in a crucible and compact it well, and put the solidified crucible into about 9 meshes.
It was produced by calcining in an electric resistance furnace at 00°C for 24 hours. Table 4 shows that the amount of AI added is 0.5%, and the amount of M in the lime crucible material is
The desulfurization rate constant and residual element amount are shown when the gO content is variously changed from 10% to 70% and desulfurization treatment is performed. It is shown that the desulfurization rate constant is large when the crucible material is 30% and 50%. Figure 5 shows CaO with A10.5% added.
The relationship between the amount of MgO mixed in the crucible, the achieved desulfurization value, the amount of residual Mg, and the desulfurization rate constant is shown. As shown in Table 5, the dissolved metal is 300 ppm in electrolytic iron.
15% Mg0 in a CaO crucible.
, 50% MgO, 70% MgO added CaO-Mg
Using an O crucible, 0.3% by weight of AI and 0.3% by weight of Ca.
0.5% by weight of AI7-Ca clad wire consisting of 2% by weight is added, and the desulfurization rate constant and the analysis value (ppm) of each element 10 minutes after adding the Af-Ca clad wire are shown. Here S. ... Initial sulfur amount S, ... Parallel sulfur amount tl ... Time until equilibrium is reached. Figure 5 shows the composition AI 0.3%, CaO, 2% A
The relationship between the amount of Mg mixed in CaO, the achieved desulfurization value, the desulfurization rate constant, the amount of residual Mg, and the amount of residual Ca when 0.5% of l-Ca clad material is added to molten metal is shown. As is clear from Figure 5, MgO was added to the CaO crucible for 15~
75% by weight was used, and Af-
When using Ca-clad wire, the amount of sulfur reached is I p
pm (0, ooo 1%), showing extremely good results. Examples 13-15 The molten metal was C22%, Co2%, Fe18%
Example 14. Hastelloy Example 15 is Ca
The ratio of O-CaF2-Al2O3 is 6:3:1. Add ioog of flux, dissolve 2Kg, and dissolve CaO-5
Table 6 shows the effect of adding flux when 0% MgO crucible material was used repeatedly. Example 13 shows that flux was added the first time the crucible material was used repeatedly, and Example 14 showed that flux was added the fifth time the crucible material was used repeatedly.
Example 15 is a case where the crucible was used repeatedly up to the fifth time and no flux was added. Table 7 shows the composition of the high purity calcia (cab) crucible used, and Table 8 shows the composition of the high purity MgO used for mixing in this calcia crucible. Table 9 shows the electrolytic iron composition (% by weight) used. Note: Analytical value S after melting and before addition of Al: 300 ppm: Adjusted by adding FeS 0
...300 ppm N...40 ppm The analytical values after dissolution and before addition of Al are as follows. S = 300 ppm (adjust S amount by adding Fe S) 0...300 ppm N...40 ppm Example 16 D B was actually tested using the examples and comparative examples shown in the table below.
T T (Ductile - brittle tr
The results of the measurements are shown in Table 1θ, and the results will be described below. The raw material used was electrolytic iron, and in Comparative Example A, the composition was dissolved in a CaO crucible: 0:8 ppm, S: 5 pI)m. Mg<lppm, Ca1lOppm. Example B has a composition of 0: 7 ppm, S: 1 ppm. Mg=27ppm, ca=10ppm. DBTT was measured by measuring the temperature at which the impact absorption energy value changes using a Charpy type test piece. From the above measurement results, it was found that in the present molten steel (sample B), the composition as claimed in the claims has a very large effect on toughness and malleability. Example 17 A creep rupture life test was conducted using AI S 1316 steel. The chemical compositions of Examples and Comparative Examples are shown in Table 12. Table 13 shows the results of a comparison of creep rupture life at 550°C. The test piece at this time had a parallel part diameter of 6 mm.
φ, distance between gauges: 30 mm, stress value 35 kg/mm
It is 2. From this result as well, great effects were recognized within the claimed scope of the composition of the present invention.

[Brief explanation of drawings]

FIG. 1 is a graph showing the relationship between the MgO content of the basic refractory of the container, the desulfurization rate constant (K), the amount of sulfur reached, and the amount of residual Mg when 0.5% of Al is added. Figure 2 shows the AI
It is a graph showing changes over time in residual AI amount and desulfurization ability after addition of 0.5%. FIG. 3 is a graph showing changes in deoxidizing ability, desulfurizing ability, and nitrogen content over time in the molten alloys according to Example I and Example 2. Figure 4 shows the M of CaO crucible (comparative example) and CaOMgO crucible.
AL 0.5% in various crucibles with different amounts of gO.
FIG. 2 is a characteristic diagram showing changes over time in desulfurization ability when added. Figure 5 shows Af by changing the amount of MgO in the CaO-MgO crucible.
-The amount of sulfur achieved when adding 0.5% of Ca cladding material,
It is a characteristic diagram showing the relationship between the desulfurization rate constant, the amount of residual Mg, and the amount of residual Ca.

Claims (1)

[Claims] 1. (a) A crucible and a crucible furnace made of a basic refractory containing 15 to 75% by weight of MgO and 15 to 85% by weight of CaO, a crucible supported by the refractory, and a crucible furnace , melting furnace (V
charging a molten alloy substantially consisting of at least one main component selected from the group consisting of Fe, Co and Ni in one vessel selected from the group consisting of (OD, AOD) converter and ladle; , (b) under one atmosphere selected from the group consisting of a non-oxidizing atmosphere and a vacuum, a first additive made of either aluminum (Al) or an aluminum alloy, and titanium (Ti) or zirconium. (Zr), niobium (Nb
) and a second additive selected from the group consisting of rare earth elements; (c) placing the molten alloy in an atmosphere selected from the group consisting of a non-oxidizing atmosphere or a vacuum; Below, deoxidation, desulfurization,
(d) obtaining a molten alloy consisting of 0.005 to 7.0% residual aluminum, 0.0001 to 0.005% residual calcium, and 0.0001 to 0.03% residual magnesium; The step of agglomerating the molten alloy with oxygen of 0.003% or less, sulfur of 0.010% or less, nitrogen 0
．． Iron and nickel with extremely low content of 0.3% or less
, and a method for producing a cobalt-based alloy. 2. (a) A crucible, a crucible furnace, a crucible, a crucible furnace, a melting furnace (V
iron-based, nickel-based
(b) charging the molten alloy with at least one main component selected from the group consisting of cobalt groups; a first additive made of aluminum or an aluminum alloy; a second additive selected from the group consisting of titanium, zirconium, niobium, and rare earth elements; and an alkali metal or alkaline earth metal. a step of adding 5% or less of a flux containing at least one selected from the group consisting of oxides, halides, silicates, carbonates, and aluminum oxides to the molten alloy; (c ) The molten alloy is deoxidized, desulfurized, and denitrified in an atmosphere selected from the group consisting of a non-oxidizing atmosphere or a vacuum, and the residual aluminum is 0.005 to 7.0% and the residual calcium is 0.00%. 0001 to 0.005%, residual magnesium 0.0001 to 0.03%, and (d) forming an ingot of the obtained molten alloy. A method for producing iron-, nickel-, or cobalt-based alloys having extremely low sulfur contents of 0.010% or less and nitrogen contents of 0.03% or less. (a) 15-75% by weight MgO and 15-85% by weight
A crucible, a crucible furnace, a crucible, a crucible furnace, a melting furnace (VOD
, AOD) converter and ladle, melting an alloy substantially consisting of at least one main component selected from iron, cobalt and nickel; ) a first additive selected from the group consisting of aluminum and aluminum alloys, and titanium, zirconium, niobium and a second additive selected from the group consisting of rare earth elements, a third additive selected from boron, alkali metals and alkaline earth metals, oxides and halides of alkali metals and alkaline earth metals, silicate,
(c) desulfurization, deoxidation, and denitrification by adding not more than 5% of the molten metal to a flux selected from the group consisting of carbides and carbonates, and oxides of aluminum; The process of deoxidizing, desulfurizing, and agglomerating the denitrified molten alloy is an extremely low iron content of 0.003% or less of oxygen, 0.010% or less of sulfur, and 0.010% or less of nitrogen. , nickel, and cobalt
Method for manufacturing base alloys. 4. The method according to any one of claims 1 to 3, wherein the non-oxidizing atmosphere is an argon gas atmosphere. 5. The flux is an alkali metal, alkaline earth metal oxide, halide, silicate, carbonate, fluoride,
4. The method according to claim 2, which comprises at least one selected from the group consisting of carbides and aluminum oxides. 6. The method according to any one of claims 2 to 3, wherein the flux comprises calcium oxide and calcium fluoride.