CN103468964B - New slag system for synchronously controlling hydrogen-oxygen content of electroslag ingot and preparation method thereof - Google Patents

Abstract

The invention discloses a new slag system for synchronously controlling the hydrogen-oxygen content of an electroslag ingot and a preparation method thereof, belonging to the technical field of an electroslag remelting slag system. The slag system comprises the following components in percentage by weight: 43-47% of CaF2, 18-22% of CaO, 4-6% of Al2O3, 8-12% of MgO, 14-16% of Ce2O3 and 4-6% of La2O3. The preparation method comprises the steps of proportionally preparing slag charge according to the components of the slag system and the weight percentage requirements, wherein the slag charge comprises limestone, dolomite, fluorite, bauxite, cerium oxide powder and lanthanum oxide powder; pre-melting the mixed slag charge at 1,600 DEG C, wherein the pre-melting process is performed by use of an Fe-Al electrode in an electroslag melting device; pouring the liquid-state slag charge into a steel mould; after the product is cooled, breaking and packaging. By adopting the new slag system and preparation method disclosed by the invention, the oxygen content increase of the electroslag ingot in the electroslag remelting process can be controlled to be less than 0.0008%, and the hydrogen content increase can be controlled to be less than 0.0003%, thereby achieving an aim of synchronously controlling the hydrogen content and oxygen content in the electroslag ingot.

Description

A kind of slag system simultaneously controlling ESR ingot hydrogen-oxygen content

Technical field

The invention belongs to electroslag remelting slag technical field, more particularly, relate to slag system of a kind of ESR ingot of control simultaneously hydrogen-oxygen content and preparation method thereof.

Background technology

Slag system has important effect in esr process, and it is not only related to whether carrying out smoothly of esr process, the more important thing is to have conclusive impact to the quality of ESR ingot.At present, conventional electroslag remelting slag has following two shortcomings:

(1) oxygen level in steel ingot can not effectively be controlled.Current research and production practice all find, when the oxygen in electrode is down to certain level, after esr, not only can not reduce the content of oxygen, there will be certain increasing on the contrary.No matter be the little ingot of hundreds of kilogram weight or weigh the large ingot of tens tons, all there is this problem at present.

Affect the principal element of oxygen level in ESR ingot to have: the oxygen in original electrodes and inclusion; The oxidation on slag bath upper electrode surface and the impact of remelting slag; The constituent element of slag.In modern process for making, the oxygen level of original electrodes can control to very low level, therefore can not to Electroslag Process oxygenation; Electrode above slag bath at high temperature can be oxidized, but constantly adds reductor due to Electroslag Process, therefore also can not to Electroslag Process oxygenation.To the constituent element of esr process oxygenation mainly slag, particularly at high temperature unstable oxide compound is easy to decomposite oxygen and enters ESR ingot.Constituent element mainly Al unstable in remelting slag ₂o ₃, it at high temperature decomposes as follows:

$\left[{\mathrm{Al}}_2{O}_3\right]\⇔\left[\mathrm{Al}\right]+\left[O\right]$

The oxygen decomposed and aluminium enter in metal pool, and along with the cooling of metal pool, aluminium and oxygen recombine into aluminum oxide and is present in ESR ingot, thus cause oxygen level increase, inclusion increase.

(2) hydrogen richness in steel ingot can not effectively be controlled.In esr process, common slag system not only can not effectively be removed [H] in electrode, but also there is increasing hydrogen phenomenon, and particularly for large-sized casting ingot, this phenomenon is more serious.And hydrogen has very large harm in steel, easily produce the defects such as white point, drastically influence the performance of steel.

In esr process, the source of hydrogen mainly comprises the following aspects: the hydrogen richness in electrode; Moisture in air; The moisture of condensation on electrode and crystallizer cold surface; The moisture absorbed in slag.Electrode is general, and all through vacuum-treat, hydrogen richness is very low, can not cause and increase hydrogen phenomenon; In esr process, adopt dry air to protect, atmosphere moisture can be avoided the impact of hydrogen; Adopt hot water to start and can avoid crystallizer surface condensation water mitigation.Therefore, ESR ingot increases the constituent element that the key link of hydrogen is slag.And the energy-conservation slag containing CaO extensively adopted at present, CaO very easily reacts with water, causes the moisture in slag to increase, and can be decomposed into hydrogen enter ESR ingot in reflow process.By literature search, inquire the patent that two pieces prevents from increasing hydrogen, its publication number is respectively CN1078500, CN101654742.Publication number is that the patent of CN1078500 mainly adopts dry air to avoid wet weather on the impact of esr process, does not consider the impact of slag system, therefore can not stop the infiltration of hydrogen completely.Publication number is the patent of CN101654742, and major measure of its control hydrogen adopts MgO to replace part CaO, prevent the moisture absorption of CaO, but MgO also can the moisture absorption, so can not stop the infiltration of hydrogen completely, all contains higher Al in above two kinds of slag systems simultaneously ₂o ₃, therefore effectively cannot control the oxygen level of ESR ingot.

In sum, electro slag remelting slag of the prior art ties up to the oxygen level controlled in steel ingot, hydrogen richness aspect does not all reach perfect condition.Along with the raising to ferrous materials specification of quality, the research of Clean Steel becomes the emphasis of the recent industrialization of metallurgy industry, and in esr process, how to control ESR ingot oxygen level, hydrogen richness are the difficult problems always perplexing extraordinary smelter simultaneously.

Summary of the invention

1. invent the technical problem that will solve

The object of the invention is to overcome the deficiency that electroslag remelting slag in prior art effectively can not control oxygen level in steel ingot, hydrogen richness, provide slag system of a kind of ESR ingot of control simultaneously hydrogen-oxygen content and preparation method thereof, adopt technical scheme of the present invention, the slag system prepared possesses hypoxemia, low hydrogen permeability, can reduce the content of esr process steel ingot hydrogen, oxygen.

2. technical scheme

For achieving the above object, technical scheme provided by the invention is:

A kind of slag system simultaneously controlling ESR ingot hydrogen-oxygen content of the present invention, slag system ingredient and weight percent are: CaF ₂: 43 ~ 47%, CaO:18 ~ 22%, Al ₂o ₃: 4 ~ 6%, MgO:8 ~ 12%, Ce ₂o ₃: 14 ~ 16%, La ₂o ₃: 4 ~ 6%.The weight percent of middle rare earth of the present invention controls as Ce ₂o ₃: 14 ~ 16%, La ₂o ₃: 4 ~ 6%, select Ce in slag system ₂o ₃and La ₂o ₃reason be that the slag system that it combinationally uses is thermally-stabilised best, the trend to metal pool oxygen supply is minimum, is conducive to controlling the oxygen level of steel ingot; Meanwhile, Ce in the present invention is adopted ₂o ₃and La ₂o ₃ratio, both activity can be reduced further, improve its thermostability.

Further, this slag system has following physicochemical property:

(a) fusing point: 1300 ~ 1350 DEG C; Specific conductivity: 3.0 ~ 4.0S.cm ^-1; Viscosity: 0.2 ~ 0.3Pa.s;

(b) T [O] increment <0.0008%, the total oxygen increasing amount after namely adopting this slag system esr in ESR ingot is no more than 8ppm;

C () T [H] increment <0.0003%, the perhydro increasing amount after namely adopting this slag system esr in ESR ingot is no more than 3ppm.

A kind of preparation method simultaneously controlling the slag system of ESR ingot hydrogen-oxygen content of the present invention, the steps include:

Step one, according to preparing slag system component and weight percent requirement configures slag charge in proportion, and to mix, slag charge is Wingdale, rhombspar, fluorite, bauxitic clay, ceria oxide powder and lanthanum oxide powder, and wherein, slag system ingredient and weight percent are: CaF ₂: 43 ~ 47%, CaO:18 ~ 22%, Al ₂o ₃: 4 ~ 6%, MgO:8 ~ 12%, Ce ₂o ₃: 14 ~ 16%, La ₂o ₃: 4 ~ 6%;

Step 2, by mixing slag charge fritting at 1600 DEG C of temperature of step one gained, Pre melting process adopts Fe-Al electrode to carry out in electroslag melting device, the arcing that has been energized slag, melting voltage is 40 ~ 45V, melting electric current is 3000 ~ 4000A, smelting time is 30min, wherein electroslag melting device comprises transformer, Fe-Al electrode, water tank at the bottom of copper, water-in, water outlet, steel plate and magnesia carbon brick layer, at the bottom of described copper, water tank is as container bottom, described steel plate and the combination of magnesia carbon brick layer are as container side wall, and water tank at the bottom of copper adopts water-cooling pattern cooling, at the bottom of copper, one end of water tank is provided with water-in, the other end is provided with water outlet, described Fe-Al electrode, at the bottom of copper, water tank is connected to transformer respectively, Fe-Al electrode inserts in the slag charge of electroslag melting device inside,

Step 3, after step 2 melting, liquid slag charge is poured in punching block, after cooling crushing packing.

Preferably, the mass percent >54% of CaO in described Wingdale, granularity 2 ~ 5mm; The mass percent >30% of the mass percent >20% of MgO, CaO in rhombspar, granularity 2 ~ 5mm; CaF in fluorite ₂mass percent >90%, granularity is less than 1mm; Al in bauxitic clay ₂o ₃mass percent >76%, granularity is less than 1mm; Ce in ceria oxide powder ₂o ₃mass percent >95%, granularity <1mm; La in lanthanum oxide powder ₂o ₃mass percent >95%, granularity <1mm.

The theoretical foundation of the slag system of a kind of ESR ingot of control simultaneously hydrogen-oxygen content of the present invention is as described below:

1) major reason that in esr process, ESR ingot oxygen level increases is exactly because the decomposition of constituent element unstable in high temperature slag caused.Unstable constituent element main in esr slag system is Al ₂o ₃, therefore must manage to reduce Al in slag ₂o ₃activity.And the stability of rare earth slag is very strong, replace part Al with it ₂o ₃effectively can control the oxygenation of esr process, rare earth slag also has certain specific conductivity simultaneously, can ensure carrying out smoothly of reflow process.2) in esr process, the major cause of ESR ingot increasing hydrogen (particularly the remelting initial stage increases hydrogen) there is certain moisture in slag.Adopt Wingdale, rhombspar to replace lime, MgO in the present invention, main purpose utilizes the CO discharged in melting initial stage (that is: Pre melting process) Wingdale, rhombspar ₂small bubbles absorb the moisture in slag, thus play hydrogen richness in reduction slag, reduce hydrogen richness in ingot casting further.

3. beneficial effect

Adopt technical scheme provided by the invention, compared with existing known technology, there is following unusual effect:

(1) a kind of slag system simultaneously controlling ESR ingot hydrogen-oxygen content of the present invention, rare earth component stability is wherein very strong, replaces part Al in common slag system with it ₂o ₃effectively can control the oxygenation of esr process, total oxygen increasing amount after adopting slag system esr of the present invention in ESR ingot is no more than 8ppm, thus the total amount of inclusion in control ingot casting, rare earth slag also has certain specific conductivity simultaneously, can ensure carrying out smoothly of reflow process; In addition, rhombspar, Wingdale is adopted to be control the free water content in slag as the main purpose of raw material, effectively can reduce the hydrogen richness of esr process ingot casting, perhydro increasing amount after adopting slag system esr of the present invention in ESR ingot is no more than 3ppm, thus the long term annealing operation carried out owing to increasing hydrogen can be reduced, technical scheme of the present invention significantly improves production efficiency and economic benefit, so can control hydrogen richness in ESR ingot and oxygen level simultaneously;

(2) a kind of preparation method simultaneously controlling the slag system of ESR ingot hydrogen-oxygen content of the present invention, the configuration of its slag charge adopts Wingdale, rhombspar replace lime, MgO, main purpose utilizes the CO discharged in melting initial stage Wingdale, rhombspar ₂small bubbles absorb the moisture in slag, thus play hydrogen richness in reduction slag, reduce hydrogen richness in ingot casting further, and compared to adopting MgO to replace part CaO to prevent the moisture absorption of CaO in prior art, the present invention almost can stop the infiltration of hydrogen completely;

(3) a kind of preparation method simultaneously controlling the slag system of ESR ingot hydrogen-oxygen content of the present invention, its Pre melting process adopts Fe-Al electrode to carry out in specific electroslag melting device, and melting voltage is 40 ~ 45V, melting electric current is 3000 ~ 4000A, smelting time is 30min, make the fritting effect of slag charge best, facilitate during esr and use.

Accompanying drawing explanation

Fig. 1 is the structural representation of electroslag melting device in the present invention.

Label declaration in schematic diagram:

1, transformer; 2, Fe-Al electrode; 3, water tank at the bottom of copper; 4, water-in; 5, water outlet; 6, steel plate; 7, magnesia carbon brick layer.

Embodiment

For understanding content of the present invention further, below in conjunction with embodiment and accompanying drawing, the invention will be further described.

Embodiment 1

A kind of slag system simultaneously controlling ESR ingot hydrogen-oxygen content of the present embodiment, slag system ingredient and weight percent are: CaF ₂: 43%, CaO:22%, Al ₂o ₃: 6%, MgO:8%, Ce ₂o ₃: 16%, La ₂o ₃: 5%.The step of its preparation method is specially:

Step one, according to preparing slag system component and weight percent requirement configures slag charge in proportion, and mix, slag charge is Wingdale, rhombspar, fluorite, bauxitic clay, ceria oxide powder and lanthanum oxide powder, and the slag system ingredient of the present embodiment and weight percent are: CaF ₂: 43%, CaO:22%, Al ₂o ₃: 6%, MgO:8%, Ce ₂o ₃: 16%, La ₂o ₃: 5%; Wherein: the mass percent >54% of CaO in described Wingdale, granularity 2 ~ 5mm; The mass percent >30% of the mass percent >20% of MgO, CaO in rhombspar, granularity 2 ~ 5mm; CaF in fluorite ₂mass percent >90%, granularity is less than 1mm; Al in bauxitic clay ₂o ₃mass percent >76%, granularity is less than 1mm; Ce in ceria oxide powder ₂o ₃mass percent >95%, granularity <1mm; La in lanthanum oxide powder ₂o ₃mass percent >95%, granularity <1mm; In the present embodiment, the Task-size Controlling of Wingdale, rhombspar is within the scope of 2 ~ 5mm, be in order to be conducive to Wingdale, rhombspar at high temperature evenly, stable, continue discharge CO ₂bubble, thus the moisture in maximum absorption slag system; Then, the Task-size Controlling of other component in the scope being less than 1mm, mainly for making slag charge rapid melting, in prior art be all generally by the Task-size Controlling of all components within 1mm.

Step 2, by mixing slag charge fritting at 1600 DEG C of temperature of step one gained, Pre melting process adopts Fe-Al electrode to carry out in electroslag melting device, the arcing that has been energized slag, melting voltage is 40 ~ 42V, melting electric current is 3800 ~ 4000A, smelting time is 30min, wherein electroslag melting device comprises transformer 1, Fe-Al electrode 2, water tank 3 at the bottom of copper, water-in 4, water outlet 5, steel plate 6 and magnesia carbon brick layer 7 (as shown in Figure 1), at the bottom of described copper, water tank 3 is as container bottom, at the bottom of copper, the bottom of water tank 3 is welded with copper bar, be connected by the low pressure end of water-cooled cable with transformer 1, described steel plate 6 and magnesia carbon brick layer 7 combine as container side wall, and water tank 3 adopts water-cooling pattern to cool at the bottom of copper, at the bottom of copper, one end of water tank 3 is provided with water-in 4, the other end is provided with water outlet 5, wherein the water temperature of water-in 4 is not higher than 30 DEG C, hydraulic pressure is 0.2 ~ 0.3MPa, described Fe-Al electrode 2, at the bottom of copper, water tank 3 is connected to transformer 1 respectively, Fe-Al electrode 2 inserts in the slag charge of electroslag melting device inside, in this Fe-Al electrode 2, aluminum content is 2 ~ 3% (weight percents).

Step 3, after step 2 melting, liquid slag charge is poured in punching block, after cooling crushing packing.

The slag system that the present embodiment prepares has following physicochemical property: (a) fusing point: 1350 DEG C; Specific conductivity: 3.6S.cm ^-1; Viscosity: 0.25Pa.s; (b) T [O] increment <0.0008%, the total oxygen increasing amount after namely adopting this slag system esr in ESR ingot is no more than 8ppm; C () T [H] increment <0.0003%, the perhydro increasing amount after namely adopting this slag system esr in ESR ingot is no more than 3ppm.Concrete test is as follows: the ESR ingot adopting this example slag system remelting Φ 100mm, and steel grade is GCr15 bearing steel, and wherein GCr15 bearing steel is through VD vacuum-treat and continuous casting gained, and the initial hydrogen content of GCr15 bearing steel is 1ppm, and oxygen level is 10ppm; Sample position is ingot casting bottom, and its remelting effect is as shown in table 1.

The remelting effect (GCr15 bearing steel) of table 1 embodiment 1 ~ 4

Embodiment 2

A kind of slag system simultaneously controlling ESR ingot hydrogen-oxygen content of the present embodiment, slag system ingredient and weight percent are: CaF ₂: 45%, CaO:20%, Al ₂o ₃: 5%, MgO:10%, Ce ₂o ₃: 14%, La ₂o ₃: 6%.The step of its preparation method is specially:

Step one, according to preparing slag system component and weight percent requirement configures slag charge in proportion, and mix, slag charge is Wingdale, rhombspar, fluorite, bauxitic clay, ceria oxide powder and lanthanum oxide powder, and the slag system ingredient of the present embodiment and weight percent are: CaF ₂: 45%, CaO:20%, Al ₂o ₃: 5%, MgO:10%, Ce ₂o ₃: 14%, La ₂o ₃: 6%; Wherein: the mass percent >54% of CaO in described Wingdale, granularity 2 ~ 5mm; The mass percent >30% of the mass percent >20% of MgO, CaO in rhombspar, granularity 2 ~ 5mm; CaF in fluorite ₂mass percent >90%, granularity is less than 1mm; Al in bauxitic clay ₂o ₃mass percent >76%, granularity is less than 1mm; Ce in ceria oxide powder ₂o ₃mass percent >95%, granularity <1mm; La in lanthanum oxide powder ₂o ₃mass percent >95%, granularity <1mm;

Step 2, by mixing slag charge fritting at 1600 DEG C of temperature of step one gained, Pre melting process adopts Fe-Al electrode to carry out in electroslag melting device, the arcing that has been energized slag, melting voltage is 43 ~ 45V, melting electric current is 3000 ~ 3400A, smelting time is 30min, wherein electroslag melting device comprises transformer 1, Fe-Al electrode 2, water tank 3 at the bottom of copper, water-in 4, water outlet 5, steel plate 6 and magnesia carbon brick layer 7 (as shown in Figure 1), at the bottom of described copper, water tank 3 is as container bottom, described steel plate 6 and magnesia carbon brick layer 7 combine as container side wall, and water tank 3 adopts water-cooling pattern to cool at the bottom of copper, at the bottom of copper, one end of water tank 3 is provided with water-in 4, the other end is provided with water outlet 5, described Fe-Al electrode 2, at the bottom of copper, water tank 3 is connected to transformer 1 respectively, Fe-Al electrode 2 inserts in the slag charge of electroslag melting device inside,

Step 3, after step 2 melting, liquid slag charge is poured in punching block, after cooling crushing packing.

The slag system that the present embodiment prepares has following physicochemical property: (a) fusing point: 1330 DEG C; Specific conductivity: 3.0S.cm ^-1; Viscosity: 0.2Pa.s; (b) T [O] increment <0.0008%, the total oxygen increasing amount after namely adopting this slag system esr in ESR ingot is no more than 8ppm; C () T [H] increment <0.0003%, the perhydro increasing amount after namely adopting this slag system esr in ESR ingot is no more than 3ppm.Concrete test is as follows: the ESR ingot adopting this example slag system remelting Φ 100mm, and steel grade is GCr15 bearing steel, and wherein GCr15 bearing steel is through VD vacuum-treat and continuous casting gained, and the initial hydrogen content of GCr15 bearing steel is 1ppm, and oxygen level is 10ppm; Sample position is ingot casting bottom, and its remelting effect is as shown in table 1.

Embodiment 3

A kind of slag system simultaneously controlling ESR ingot hydrogen-oxygen content of the present embodiment, slag system ingredient and weight percent are: CaF ₂: 47%, CaO:18%, Al ₂o ₃: 4%, MgO:12%, Ce ₂o ₃: 14%, La ₂o ₃: 5%.The step of its preparation method is specially:

Step one, according to preparing slag system component and weight percent requirement configures slag charge in proportion, and mix, slag charge is Wingdale, rhombspar, fluorite, bauxitic clay, ceria oxide powder and lanthanum oxide powder, and the slag system ingredient of the present embodiment and weight percent are: CaF ₂: 47%, CaO:18%, Al ₂o ₃: 4%, MgO:12%, Ce ₂o ₃: 14%, La ₂o ₃: 5%; Wherein: the mass percent >54% of CaO in described Wingdale, granularity 2 ~ 5mm; The mass percent >30% of the mass percent >20% of MgO, CaO in rhombspar, granularity 2 ~ 5mm; CaF in fluorite ₂mass percent >90%, granularity is less than 1mm; Al in bauxitic clay ₂o ₃mass percent >76%, granularity is less than 1mm; Ce in ceria oxide powder ₂o ₃mass percent >95%, granularity <1mm; La in lanthanum oxide powder ₂o ₃mass percent >95%, granularity <1mm;

Step 2, by mixing slag charge fritting at 1600 DEG C of temperature of step one gained, Pre melting process adopts Fe-Al electrode to carry out in electroslag melting device, the arcing that has been energized slag, melting voltage is 42 ~ 44V, melting electric current is 3400 ~ 3800A, smelting time is 30min, wherein electroslag melting device comprises transformer 1, Fe-Al electrode 2, water tank 3 at the bottom of copper, water-in 4, water outlet 5, steel plate 6 and magnesia carbon brick layer 7 (as shown in Figure 1), at the bottom of described copper, water tank 3 is as container bottom, described steel plate 6 and magnesia carbon brick layer 7 combine as container side wall, and water tank 3 adopts water-cooling pattern to cool at the bottom of copper, at the bottom of copper, one end of water tank 3 is provided with water-in 4, the other end is provided with water outlet 5, described Fe-Al electrode 2, at the bottom of copper, water tank 3 is connected to transformer 1 respectively, Fe-Al electrode 2 inserts in the slag charge of electroslag melting device inside,

Step 3, after step 2 melting, liquid slag charge is poured in punching block, after cooling crushing packing.

The slag system that the present embodiment prepares has following physicochemical property: (a) fusing point: 1300 DEG C; Specific conductivity: 4.0S.cm ^-1; Viscosity: 0.3Pa.s; (b) T [O] increment <0.0008%, the total oxygen increasing amount after namely adopting this slag system esr in ESR ingot is no more than 8ppm; C () T [H] increment <0.0003%, the perhydro increasing amount after namely adopting this slag system esr in ESR ingot is no more than 3ppm.Concrete test is as follows: the ESR ingot adopting this example slag system remelting Φ 100mm, and steel grade is GCr15 bearing steel, and wherein GCr15 bearing steel is through VD vacuum-treat and continuous casting gained, and the initial hydrogen content of GCr15 bearing steel is 1ppm, and oxygen level is 10ppm; Sample position is ingot casting bottom, and its remelting effect is as shown in table 1.

Embodiment 4

A kind of slag system simultaneously controlling ESR ingot hydrogen-oxygen content of the present embodiment, slag system ingredient and weight percent are: CaF ₂: 44%, CaO:21%, Al ₂o ₃: 4%, MgO:12%, Ce ₂o ₃: 15%, La ₂o ₃: 4%.The step of its preparation method is specially:

Step one, according to preparing slag system component and weight percent requirement configures slag charge in proportion, and mix, slag charge is Wingdale, rhombspar, fluorite, bauxitic clay, ceria oxide powder and lanthanum oxide powder, and the slag system ingredient of the present embodiment and weight percent are: CaF ₂: 44%, CaO:21%, Al ₂o ₃: 4%, MgO:12%, Ce ₂o ₃: 15%, La ₂o ₃: 4%; Wherein: the mass percent >54% of CaO in described Wingdale, granularity 2 ~ 5mm; The mass percent >30% of the mass percent >20% of MgO, CaO in rhombspar, granularity 2 ~ 5mm; CaF in fluorite ₂mass percent >90%, granularity is less than 1mm; Al in bauxitic clay ₂o ₃mass percent >76%, granularity is less than 1mm; Ce in ceria oxide powder ₂o ₃mass percent >95%, granularity <1mm; La in lanthanum oxide powder ₂o ₃mass percent >95%, granularity <1mm;

Step 2, by mixing slag charge fritting at 1600 DEG C of temperature of step one gained, Pre melting process adopts Fe-Al electrode to carry out in electroslag melting device, the arcing that has been energized slag, melting voltage is 42 ~ 44V, melting electric current is 3500 ~ 3800A, smelting time is 30min, wherein electroslag melting device comprises transformer 1, Fe-Al electrode 2, water tank 3 at the bottom of copper, water-in 4, water outlet 5, steel plate 6 and magnesia carbon brick layer 7 (as shown in Figure 1), at the bottom of described copper, water tank 3 is as container bottom, described steel plate 6 and magnesia carbon brick layer 7 combine as container side wall, and water tank 3 adopts water-cooling pattern to cool at the bottom of copper, at the bottom of copper, one end of water tank 3 is provided with water-in 4, the other end is provided with water outlet 5, described Fe-Al electrode 2, at the bottom of copper, water tank 3 is connected to transformer 1 respectively, Fe-Al electrode 2 inserts in the slag charge of electroslag melting device inside,

Step 3, after step 2 melting, liquid slag charge is poured in punching block, after cooling crushing packing.

The slag system that the present embodiment prepares has following physicochemical property: (a) fusing point: 1328 DEG C; Specific conductivity: 3.6S.cm ^-1; Viscosity: 0.27Pa.s; (b) T [O] increment <0.0008%, the total oxygen increasing amount after namely adopting this slag system esr in ESR ingot is no more than 8ppm; C () T [H] increment <0.0003%, the perhydro increasing amount after namely adopting this slag system esr in ESR ingot is no more than 3ppm.Concrete test is as follows: the ESR ingot adopting this example slag system remelting Φ 100mm, and steel grade is GCr15 bearing steel, and wherein GCr15 bearing steel is through VD vacuum-treat and continuous casting gained, and the initial hydrogen content of GCr15 bearing steel is 1ppm, and oxygen level is 10ppm; Sample position is ingot casting bottom, and its remelting effect is as shown in table 1.

In embodiment 1 ~ 4, adopt Ce ₂o ₃and La ₂o ₃replace partial oxidation aluminium, and adopt the oxygen level increase that Wingdale, rhombspar replace lime, MgO can control esr process ESR ingot to be less than 0.0008%, hydrogen richness increase is less than 0.0003%, reach the object simultaneously controlling hydrogen richness in ESR ingot and oxygen level, solve the difficult problem always perplexing extraordinary smelter.

Claims (2)

1. control a slag system for ESR ingot hydrogen-oxygen content simultaneously, it is characterized in that: slag system ingredient and weight percent are: CaF ₂: 43 ~ 47%, CaO:18 ~ 22%, Al ₂o ₃: 4 ~ 6%, MgO:8 ~ 12%, Ce ₂o ₃: 14 ~ 16%, La ₂o ₃: 4 ~ 6%; The step of its preparation method is:

Step one, according to preparing slag system component and weight percent requirement configures slag charge in proportion, and mix, slag charge is Wingdale, rhombspar, fluorite, bauxitic clay, ceria oxide powder and lanthanum oxide powder, wherein: the mass percent >54% of CaO in described Wingdale, granularity 2 ~ 5mm; The mass percent >30% of the mass percent >20% of MgO, CaO in rhombspar, granularity 2 ~ 5mm;

Step 2, by mixing slag charge fritting at 1600 DEG C of temperature of step one gained, Pre melting process adopts Fe-Al electrode to carry out in electroslag melting device, the arcing that has been energized slag, and melting voltage is 40 ~ 45V, melting electric current is 3000 ~ 4000A, and smelting time is 30min;

Step 3, after step 2 melting, liquid slag charge is poured in punching block, after cooling crushing packing.

2. a kind of slag system simultaneously controlling ESR ingot hydrogen-oxygen content according to claim 1, is characterized in that: this slag system has following physicochemical property:

(a) fusing point: 1300 ~ 1350 DEG C; Specific conductivity: 3.0 ~ 4.0S.cm ^-1; Viscosity: 0.2 ~ 0.3Pa.s;

(b) T [O] increment <0.0008%, the total oxygen increasing amount after namely adopting this slag system esr in ESR ingot is no more than 8ppm;

C () T [H] increment <0.0003%, the perhydro increasing amount after namely adopting this slag system esr in ESR ingot is no more than 3ppm.