CN105907919B - A kind of smelting process for spring steel Control and Inclusion Removal - Google Patents

A kind of smelting process for spring steel Control and Inclusion Removal Download PDF

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Publication number
CN105907919B
CN105907919B CN201610260305.5A CN201610260305A CN105907919B CN 105907919 B CN105907919 B CN 105907919B CN 201610260305 A CN201610260305 A CN 201610260305A CN 105907919 B CN105907919 B CN 105907919B
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slag
refining
steel
stoves
argon
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CN105907919A (en
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杨虎林
叶健松
余国松
吴小良
陆军
李世伟
马军
彭勇生
方毅
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Hangzhou Iron And Steel Group Co Ltd
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    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
    • C21C7/04—Removing impurities by adding a treating agent
    • C21C7/06—Deoxidising, e.g. killing
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
    • C21C5/52—Manufacture of steel in electric furnaces
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
    • C21C7/04—Removing impurities by adding a treating agent
    • C21C7/064—Dephosphorising; Desulfurising
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
    • C21C7/04—Removing impurities by adding a treating agent
    • C21C7/076—Use of slags or fluxes as treating agents
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
    • C21C7/10—Handling in a vacuum
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00—Technologies related to metal processing
    • Y02P10/20—Recycling

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Manufacturing & Machinery (AREA)
  • Treatment Of Steel In Its Molten State (AREA)

Abstract

The invention discloses a kind of smelting process for spring steel Control and Inclusion Removal, including：1) electric furnace just refines；2) Argon；3) LF stoves refine；4) VD stoves refine；5) continuous casting；Electric furnace uses Si/Mn al-free deoxidations technique to carry out pre-deoxidation, and use active lime, complexing agent and refining slag simultaneously during just producing steel；LF stoves refining early period, control basicity of slag was 1.5~2.5 using Si/Mn al-free deoxidations technique and active lime；LF stoves refining mid-term adds in refining slag, continues thereafter with using Si/Mn al-free deoxidation techniques, continues deoxidization desulfuration, it is ensured that basicity of slag is controlled 0.7~1.4；The whole BOTTOM ARGON BLOWING of LF stoves refining.The present invention combines specific deoxidier etc. using al-free deoxidation technique and the sulfur removal technology of low alkalinity clinker, the field trash in spring steel can be controlled well, so as to improve the anti-fatigue performance of spring steel.

Description

A kind of smelting process for spring steel Control and Inclusion Removal
Technical field
The present invention relates to field of metallurgy, and in particular to a kind of smelting process for spring steel Control and Inclusion Removal.
Background technology
Spring steel is for manufacturing spring and elastic part special steel grade.With the lightness of vehicle and energy saving, Road spring own wt proposes higher requirement；The high speed of passenger train from goods train and heavy duty, the work for greatly increasing spring are born Lotus, this also proposed higher requirement to the design stress of spring.Under condition of high ground stress, due to the presence of non-metallic inclusion The continuity of matrix is destroyed, causes the uneven of metal structure, becomes the formation of crack of fatigue, the mechanical property for making metal is special It is not the fatigue limit decline of metal, eventually leads to the fracture of spring.It is happened at the automobile system of Rui Mashi companies of the U.S. in 2006 Dynamic device spring breakage accident, in India's bridge collapse accident in 2009, the overhead bridge bracket fracture accident in Min is praised in Shanghai in 2009 Deng all causing serious consequence.Therefore, to improve the fatigue behaviour of spring must just control nonmetal inclusion in steel Object, the control of the non-metallic inclusion in steel have become the important research direction for improving spring fatigue performance.
At present, the main enterprises of domestic and international spring steel production have domestic Baosteel, emerging clear special steel and Nangang；External Kobe Iron company, Datong District's special steel, Thyssen companies and Ipanema companies.It uses the smelting flow of spring steel Control and Inclusion Removal Substantially all it is：First furnace (converter or electric furnace) → refining furnace (LF+ vacuum processings) → continuous casting or molding.Wherein refinery practice is de- Oxygen is aluminium deoxidation technique mostly, using the less of al-free deoxidation technique；It is single high alkalinity clinker mostly in sulfur removal technology, adopts It is less with low alkalinity clinker.Although the total oxygen demand of steel effectively can be fallen below 15 × 10 by aluminium deoxidation technique-6Hereinafter, still exist Part richness aluminium zones easily form larger particles deoxidation products.Remaining high rigidity brittle inclusion corundum (Al in steel2O3) and aluminium Sour calcium (mCaOnAl2O3) when steel billet is processed since micro-crack cannot will be formed with steel matrix rheology, spring is in alternation Micro-crack extension is generated under the action of stress, it is very big to its Influence of Fatigue Properties, such as document《A kind of Cr-Mn series spring steel Smelting process》(application number：CN201510137575.2), using aluminium deoxidation technique.On the contrary, al-free deoxidation technique can be effective Oxygen content in steel is reduced, the high rigidity brittle inclusion that aluminium deoxidation technique is avoided to generate.Using the sulfur removal technology of high alkalinity clinker, Although the sulfur content in steel can be effectively reduced, the plastification of field trash cannot be controlled well, such as document 《The exploitation of 60Si2Mn spring steel wire rods》.On the contrary, the refining of molten steel is carried out using low alkalinity clinker, it can be effectively to being mingled with Object carries out plastification control, while can also reduce the sulfur content in steel.Therefore, the desulfurization of al-free deoxidation technique and low alkalinity clinker Technique has become the priority research areas of spring steel non-metallic inclusion control, but relevant report both domestic and external is also seldom. Such as document《Si-KILLED STEEL WIRE ROD AND SPRING SUPERING IN FATIGUE CHARECTERISTIC》(application number：JP2006356308、JP2006356309、JP2006356310、JP2006356312、 JP2006356313 it) discloses a kind of spring Si killed steel of excellent in fatigue characteristics and is obtained by this wire rod excellent The spring of different fatigue-resistance characteristics.But it is only to the component content control range of the oxide system field trash in special composition and wire rod It is determined, is not directed to the production technology of Control and Inclusion Removal.
The Chinese invention patent application that application publication number is CN 104056871A (application No. is 201310681980.1) is public A kind of spring steel wire production technology for being used to control field trash has been opened, has been included the following steps：1) it is carried out by al-free deoxidation technique It smelts；2) converter top bottom blowing；3) Ar stations Argon processing；4) LF ladle argon-blowns refine；5) vacuum processing；6) side of pouring into Base, through high speed wire rolling technique into wire rod.In the step 1), the al-free deoxidation technique of spring steel 55SiCr is smelted using Si/Mn, Control the W in molten steel[Al]＜ 47 × 10-6、a[Ca]＜ 1.5 × 10-9；Special ferrosilicon is used in the step 2), Als is controlled in steel ＜ 0.0020%；Calcined magnesite ball is added in, the addition of steel per ton is 0.5-2kg；0.06~0.20wt% of carbon control targe of tapping； Finishing slag basicity control targe R >=2.5.Although above by al-free deoxidation technique, the sulfur removal technology of high alkalinity clinker is used, Although the sulfur content in steel can be effectively reduced, the plastification of field trash cannot be controlled well.
Invention content
The present invention for the above-mentioned prior art present in technical problem, provide a kind of for spring steel Control and Inclusion Removal Smelting process, using al-free deoxidation technique and the sulfur removal technology of low alkalinity clinker, and combine specific deoxidier etc., can be to bullet Field trash in spring steel controls well, so as to improve the anti-fatigue performance of spring steel.
A kind of smelting process for spring steel Control and Inclusion Removal includes the following steps：
1) electric furnace just refines；2) Argon；3) LF stoves refine；4) VD stoves refine；5) continuous casting；
In step 1), electric furnace uses Si/Mn al-free deoxidations technique to carry out pre-deoxidation, and use simultaneously during just producing steel Active lime, complexing agent and refining slag；
In step 3), LF stoves refining early period is existed using Si/Mn al-free deoxidations technique and active lime, control basicity of slag 1.5~2.5；LF stoves refining mid-term adds in refining slag, continues thereafter with using Si/Mn al-free deoxidation techniques, continues deoxidization desulfuration, really Basicity of slag control is protected 0.7~1.4；The whole BOTTOM ARGON BLOWING of LF stoves refining.
Below as the further preferred of technical solution of the present invention：
In step 1) and step 3), refer to carry out deoxidation using ferrosilicon and ferromanganese using Si/Mn al-free deoxidation techniques, use The mode of precipitation desoxydation.
In step 1), the active lime is made of the component of following weight percentage：
Activity degree >=180；
The complexing agent is made of the component of following weight percentage：
The refining slag is made of the component of following weight percentage：
In step 1), electric furnace just refines the raw material using following weight percentage：35%~70% molten iron (low-sulfur iron Water) and 30%~65% steel scrap.
In terms of every 100 tons of raw materials, the addition of the active lime is 200~400kg, the addition of the complexing agent It measures as 150~350kg, the addition of the refining slag is 200~400kg.
The endpoint carbon content that electric furnace just refines is controlled more than 0.15%.
Electric furnace steel tapping temperature is controlled at 1620~1700 DEG C.
Electric furnace uses EBT electric furnaces, using steel, remaining slag operation technique is stayed, forbid tapping process slag, staying during electric furnace steel tapping In steel technique, it is 4%~10% that the weight percentage of steel is stayed in control.
In step 2), position Argon station is waited for suitable argon pressure and argon flow amount to be selected, using Bottom Argon Stirring with steel Subject to water is not exposed.
In step 3), the active lime is made of the component of following weight percentage：
Activity degree >=180.
The whole BOTTOM ARGON BLOWING of LF stoves refining, the refining of LF stoves uses big 400~600L/min of argon flow amount early period, in the refining of LF stoves Later stage uses small 100~200L/min of argon flow amount, 40~60min of LF stove refining times.
In step 4), VD treatment process vacuum degree be less than 67Pa, high vacuum keep more than 10min (10min~20min, into Preferred 10min~the 15min of one step), after vacuum processing argon bottom-blowing flow control it is not exposed to be subject to the top of the slag, during BOTTOM ARGON BLOWING Between >=20min (20min~40min).
In step 5), strengthen the baking to covering slag, tundish before casting, it is desirable that the baking of tundish time is more than 3 hours； Whole process protection is poured into a mould, and big packet long nozzle increases seal washer, and centre, which is unwrapped, pours packet Argon in preceding implement；Continuous casting using great Bao, in Between steel operation more than packet, using bale slag-blanking detection device, ensure the remaining molten steel 1.5 tons/stove of amount of big packet, last 1 packet casting surplus is big Tail base is poured into 10 tons, scraps processing；One tundish casting sequence is not more than 10 stoves；Pulling speed of continuous casting stabilization 1.8~ 2.4m/min, first packet molten steel overheat≤40 DEG C；The continuous packet degree of superheat≤30 DEG C, using M-EMS, forbid tundish The mouth of a river, pulling rate and degree of superheat appearance are fluctuated by a relatively large margin.Continuous casting billet is 150 × 150mm2Square billet, through high speed wire rolling technique into line Material.
The smelting process of the spring steel Control and Inclusion Removal can efficiently control the plasticity of non-metallic inclusion, reduce Non-metallic inclusion content in molten steel, the size of field trash largely can be controlled in less than 5 μm.
Compared with prior art, advantages of the present invention is as follows：
First, to the property of field trash phase, ingredient, quantity and different requirements is distributed with based on different steel grades, needle of the present invention The high Si special to spring steel 55SiCrA, high Mn features, by controlling deoxidization technique, LF refining technique, finally make spring steel clip Sundries has obtained controlling well.
2nd, using Si/Mn deoxidation smelting processes, Al, Ca content in steel are controlled, entire refining process is not used containing aluminium Material, reduces Al in molten steel2O3The source that infusibilities difficulty floating is waited to be mingled with, can obtain low melting point CaOSiO2·Al2O3MgO systems Plastic occluded foreignsubstance avoids and the harmful field trash of hardness is formed in spring steel wire, the size of stringent control spring steel inclusion, Quantity and distribution etc., make field trash be distributed in tiny, disperse state, and inclusion morphology is conducive in spring steel wire following process Drawing, around spring etc.；The size of field trash largely can be controlled in 5 μm hereinafter, can improve the drawing property of spring steel, increase simultaneously Add the fatigue limit of spring.
3rd, electric furnace adds high-quality steel scrap to be smelted as metal charge using molten iron, has not only drawn " the good degassing of converter smelting Go to be mingled with effect " the advantages of, simultaneously because carrying out that steel is stayed to tap using electric furnace with eccentric bottom, it is easy during converter smelting tapping to overcome The shortcomings that slag；In addition LF refining process uses double slag operation：It makes higher alkalisation slag early period, increases de- O, de- S dynamics, while energy Effectively finished product S contents are controlled 0.010% hereinafter, reducing the source of non-metallic inclusion in molten steel, the middle and later periods makes low So as to improve the mobility of middle and later periods clinker, good dynamic conditions is provided for inclusion content in melting steel floating for basicity slag. Therefore hot metal pretreatment technology can not only be saved using this technique, reduce production cost, improve production efficiency while Reduce the non-metallic inclusion content in molten steel.
Specific embodiment
In following embodiment, in the case of no special instruction, percentage is mass percent.
Embodiment 1
Illustrate by taking spring steel 55CrSiA productions as an example：
Process for making flow：Molten iron+- 100 tons of electric furnace with eccentric bottom of high-quality steel scrap (EBT)-waiting position -100 tons of Argon station LF Refining furnace-VD stoves-continuous casting (6 machines 6 flow).
1st, electric furnace smelting process
1) strengthen the baking to ladle before tapping, ensure the red heat state of ladle liner；
2) electric furnace smelting iron and steel stock use 40% low-sulfur molten iron and 60% high-quality steel scrap, 100 tons；
3) eaf tapping point carbon content control is more than 0.15%, and the control of electric furnace steel tapping temperature is at 1640 DEG C, EBT electric furnace steel tappings Using steel is stayed to operate, it is 6% to stay steel amount, forbids tapping process slag；
4) electric furnace steel tapping carries out Si/Mn al-free deoxidation techniques, adds in deoxidier (ferrosilicon and ferromanganese) and carries out pre-deoxidation, to the greatest extent may be used Al and Al that clinker, cylinder-packing, alloy etc. are brought into can be reduced2O3；Active lime usage amount 300kg/ stoves are added in tapping process, it is multiple Mixture usage amount 210kg/ stoves, refining slag usage amount 350kg/ stoves；Wherein active lime：CaO 90%, S 0.03%, SiO2 3%, impurity 6.97%, activity degree 190；Complexing agent：SiC 19%, CaO 20%, SiO212%, TC 34%, MgO 15%； Refining slag：CaO 40%, SiO246%, A12O33%, MgO 4%, impurity 7%.
2nd, position Argon station is waited for
It is handled using BOTTOM ARGON BLOWING, it is not exposed that argon pressure and flow are subject to the top of the slag, avoids secondary oxidation and absorbs gas.
3rd, LF refining furnace technique
1) refining adds in deoxidier (ferrosilicon and ferromanganese) and active lime early period, makes higher alkalisation white slag and carries out the fast of molten steel The de- O and de- S of speed controls finished product S≤0.010%, and refining basicity of slag early period is 1.5；
2) refining mid-term adds in refining slag, then adds the maintenance that deoxidier carries out clinker, reduces basicity of slag, continues to take off Oxygen desulfurization, refining later stage basicity of slag is 1.2；
3) argon gas controls：Whole BOTTOM ARGON BLOWING operation, big argon flow 500L/min, pressure are used after increasing C, adduction gold early period 0.65~0.75Mpa；Later stage composition adjustment in place, medium and small argon flow amount 150L/min, pressure 0.20 is used during removal of inclusions ~0.25Mpa.
4) refining time 50min.
4th, VD techniques
1) vacuum degree is less than 67Pa during VD vacuum processings, and high vacuum keeps 12min；
2) VD breaks the adjustment for forbidding carrying out ingredient after sky again；After vacuum processing argon bottom-blowing flow control with the top of the slag not Subject to exposed, time 25min.
5th, continuous casting process
1) strengthen the baking to covering slag, tundish before casting, it is desirable that 4 hours baking of tundish time；
2) whole process protection is poured into a mould, and big packet long nozzle increases seal washer, and centre, which is unwrapped, pours packet Argon in preceding implement；
3) continuous casting is using steel operation more than big packet, tundish, using bale slag-blanking detection device, the big remaining molten steel amount 1.7 of packet Ton/stove, last 1 packet casting, 11 tons of surplus pour into tail base, scrap processing；10 stove of tundish casting sequence；
4) pulling speed of continuous casting stabilization is in 2.0m/min；
5) 36 DEG C of the first packet degree of superheat；Continuous 25 DEG C of the packet degree of superheat using M-EMS, is forbidden middle water containing opening, is drawn Speed and degree of superheat appearance are fluctuated by a relatively large margin.Continuous casting billet is 150 × 150mm2Square billet, through high speed wire rolling technique into wire rod.
Embodiment 2
Illustrate by taking spring steel 55CrSiA productions as an example：
Process for making flow：Molten iron+- 100 tons of electric furnace with eccentric bottom of high-quality steel scrap (EBT)-waiting position -100 tons of Argon station LF Refining furnace-VD stoves-continuous casting (6 machines 6 flow).
1st, electric furnace smelting process
1) strengthen the baking to ladle before tapping, ensure the red heat state of ladle liner；
2) electric furnace smelting iron and steel stock use 45% low-sulfur molten iron and 55% high-quality steel scrap, 100 tons；
3) eaf tapping point carbon content control is more than 0.15%, and the control of electric furnace steel tapping temperature is at 1660 DEG C, EBT electric furnace steel tappings Using steel is stayed to operate, it is 8% to stay steel amount, forbids tapping process slag；
4) electric furnace steel tapping progress Si/Mn al-free deoxidation techniques, addition deoxidier progress pre-deoxidation, as far as possible reduction clinker, The Al and Al that cylinder-packing, alloy etc. are brought into2O3；Active lime usage amount 270kg/ stoves, complexing agent usage amount are added in tapping process 230kg/ stoves, refining slag usage amount 340kg/ stoves.Wherein active lime：CaO 92%, S 0.06%, SiO22%, impurity 5.94%, activity degree 190；Complexing agent：SiC 21%, CaO 21%, SiO211%, TC 33%, MgO 14%；Refining slag： CaO 39%, SiO247%, A12O34%, MgO 3%, impurity 7%.
2nd, position Argon station is waited for
It is handled using BOTTOM ARGON BLOWING, it is not exposed that argon pressure and flow are subject to the top of the slag, avoids secondary oxidation and absorbs gas.
3rd, LF refining furnace technique
1) refining adds in deoxidier and active lime early period, makes the quickly de- O and de- S that higher alkalisation white slag carries out molten steel, Finished product S≤0.010% is controlled, refining basicity of slag early period is 2.3；
2) refining mid-term adds in refining slag, then adds the maintenance that deoxidier carries out clinker, reduces basicity of slag, continues to take off Oxygen desulfurization, refining later stage basicity of slag is 1.4；
3) argon gas controls：Whole BOTTOM ARGON BLOWING operation, big argon flow 550L/min, pressure are used after increasing C, adduction gold early period 0.65~0.80Mpa；Later stage composition adjustment in place, medium and small argon flow amount 125L/min, pressure 0.20 is used during removal of inclusions ~0.30Mpa.
4) refining time 45min.
4th, VD techniques
1) vacuum degree is less than 67Pa during VD vacuum processings, and high vacuum keeps 14min；
2) VD breaks the adjustment for forbidding carrying out ingredient after sky again；After vacuum processing argon bottom-blowing flow control with the top of the slag not Subject to exposed, time 28min.
5th, continuous casting process
1) strengthen the baking to covering slag, tundish before casting, it is desirable that the baking of tundish time is more than 3 hours；
2) whole process protection is poured into a mould, and big packet long nozzle increases seal washer, and centre, which is unwrapped, pours packet Argon in preceding implement；
3) continuous casting is using steel operation more than big packet, tundish, using bale slag-blanking detection device, the big remaining molten steel amount 1.8 of packet Ton/stove, last 1 packet casting, 13 tons of surplus pour into tail base, scrap processing；10 stove of tundish casting sequence；
4) pulling speed of continuous casting stabilization is in 2.1m/min；
5) 35 DEG C of the first packet degree of superheat；Continuous 30 DEG C of the packet degree of superheat using M-EMS, is forbidden middle water containing opening, is drawn Speed and degree of superheat appearance are fluctuated by a relatively large margin.Continuous casting billet is 150 × 150mm2Square billet, through high speed wire rolling technique into wire rod.
Embodiment 3
Illustrate by taking spring steel 55CrSiA productions as an example：
Process for making flow：Molten iron+- 100 tons of electric furnace with eccentric bottom of high-quality steel scrap (EBT)-waiting position -100 tons of Argon station LF Refining furnace-VD stoves-continuous casting (6 machines 6 flow).
1st, electric furnace smelting process
1) strengthen the baking to ladle before tapping, ensure the red heat state of ladle liner；
2) electric furnace smelting iron and steel stock use 45% low-sulfur molten iron and 55% high-quality steel scrap, 100 tons；
3) eaf tapping point carbon content control is more than 0.15%, and the control of electric furnace steel tapping temperature is at 1680 DEG C, EBT electric furnace steel tappings Using steel is stayed to operate, it is 7% to stay steel amount, forbids tapping process slag；
4) electric furnace steel tapping progress Si/Mn al-free deoxidation techniques, addition deoxidier progress pre-deoxidation, as far as possible reduction clinker, The Al and Al that cylinder-packing, alloy etc. are brought into2O3；Active lime usage amount 270kg/ stoves, complexing agent usage amount are added in tapping process 280kg/ stoves, refining slag usage amount 240kg/ stoves.Wherein active lime：CaO 92%, S 0.06%, SiO22%, impurity 5.94%, activity degree 190；Complexing agent：SiC 21%, CaO 21%, SiO211%, TC 33%, MgO 14%；Refining slag： CaO 39%, SiO247%, A12O34%, MgO 3%, impurity 7%.
2nd, position Argon station is waited for
It is handled using BOTTOM ARGON BLOWING, it is not exposed that argon pressure and flow are subject to the top of the slag, avoids secondary oxidation and absorbs gas.
3rd, LF refining furnace technique
1) refining adds in deoxidier and active lime early period, makes the quickly de- O and de- S that higher alkalisation white slag carries out molten steel, Finished product S≤0.010% is controlled, refining basicity of slag early period is 1.9；
2) refining mid-term adds in refining slag, then adds the maintenance that deoxidier carries out clinker, reduces basicity of slag, continues to take off Oxygen desulfurization, refining later stage basicity of slag is 1.1；
3) argon gas controls：Whole BOTTOM ARGON BLOWING operation, big argon flow 450L/min, pressure are used after increasing C, adduction gold early period 0.65~0.75Mpa；Later stage composition adjustment in place, medium and small argon flow amount 130L/min, pressure 0.20 is used during removal of inclusions ~0.25Mpa.
4) refining time 60min.
4th, VD techniques
1) vacuum degree is less than 67Pa during VD vacuum processings, and high vacuum keeps 15min；
2) VD breaks the adjustment for forbidding carrying out ingredient after sky again；After vacuum processing argon bottom-blowing flow control with the top of the slag not Subject to exposed, time 35min.
5th, continuous casting process
1) strengthen the baking to covering slag, tundish before casting, it is desirable that the baking of tundish time is more than 3 hours；
2) whole process protection is poured into a mould, and big packet long nozzle increases seal washer, and centre, which is unwrapped, pours packet Argon in preceding implement；
3) continuous casting is using steel operation more than big packet, tundish, using bale slag-blanking detection device, the big remaining molten steel amount 1.5 of packet Ton/stove, last 1 packet casting, 11 tons of surplus pour into tail base, scrap processing；10 stove of tundish casting sequence；
4) pulling speed of continuous casting stabilization is in 2.1m/min；
5) 38 DEG C of the first packet degree of superheat；Continuous 27 DEG C of the packet degree of superheat using M-EMS, is forbidden middle water containing opening, is drawn Speed and degree of superheat appearance are fluctuated by a relatively large margin.Continuous casting billet is 150 × 150mm2Square billet, through high speed wire rolling technique into wire rod.
Embodiment 4
Illustrate by taking spring steel 55CrSiA productions as an example：
Process for making flow：Molten iron+- 100 tons of electric furnace with eccentric bottom of high-quality steel scrap (EBT)-waiting position -100 tons of Argon station LF Refining furnace-VD stoves-continuous casting (6 machines 6 flow).
1st, electric furnace smelting process
1) strengthen the baking to ladle before tapping, ensure the red heat state of ladle liner；
2) electric furnace smelting iron and steel stock use 50% low-sulfur molten iron and 50% high-quality steel scrap, 100 tons；
3) eaf tapping point carbon content control is more than 0.15%, and the control of electric furnace steel tapping temperature is at 1670 DEG C, EBT electric furnace steel tappings Using steel is stayed to operate, it is 8% to stay steel amount, forbids tapping process slag；
4) electric furnace steel tapping progress Si/Mn al-free deoxidation techniques, addition deoxidier progress pre-deoxidation, as far as possible reduction clinker, The Al and Al that cylinder-packing, alloy etc. are brought into2O3；Active lime usage amount 290kg/ stoves, complexing agent usage amount are added in tapping process 200kg/ stoves, refining slag usage amount 350kg/ stoves.Wherein active lime：CaO 90%, S 0.03%, SiO23%, impurity 6.97%, activity degree 190；Complexing agent：SiC 19%, CaO 20%, SiO212%, TC 34%, MgO 15%；Refining slag： CaO 40%, SiO246%, A12O33%, MgO 4%, impurity 7%.
2nd, position Argon station is waited for
It is handled using BOTTOM ARGON BLOWING, it is not exposed that argon pressure and flow are subject to the top of the slag, avoids secondary oxidation and absorbs gas.
3rd, LF refining furnace technique
1) refining adds in deoxidier and active lime early period, makes the quickly de- O and de- S that higher alkalisation white slag carries out molten steel, Finished product S≤0.010% is controlled, refining basicity of slag early period is 1.7；
2) refining mid-term adds in refining slag, then adds the maintenance that deoxidier carries out clinker, reduces basicity of slag, continues to take off Oxygen desulfurization, refining later stage basicity of slag is 0.9；
3) argon gas controls：Whole BOTTOM ARGON BLOWING operation, 420~450L/min of big argon flow is used after increasing C, adduction gold early period, 0.6~0.8Mpa of pressure；Later stage composition adjustment in place, medium and small 110~140L/min of argon flow amount, pressure is used during removal of inclusions 0.20~0.30Mpa of power.
4) refining time 55min.
4th, VD techniques
1) vacuum degree is less than 67Pa during VD vacuum processings, and high vacuum keeps 10min；
2) VD breaks the adjustment for forbidding carrying out ingredient after sky again；After vacuum processing argon bottom-blowing flow control with the top of the slag not Subject to exposed, time 33min.
5th, continuous casting process
1) strengthen the baking to covering slag, tundish before casting, it is desirable that the baking of tundish time is more than 3 hours；
2) whole process protection is poured into a mould, and big packet long nozzle increases seal washer, and centre, which is unwrapped, pours packet Argon in preceding implement；
3) continuous casting is using steel operation more than big packet, tundish, using bale slag-blanking detection device, the big remaining molten steel amount 1.8 of packet Ton/stove, last 1 packet casting, 12 tons of surplus pour into tail base, scrap processing；10 stove of tundish casting sequence；
4) pulling speed of continuous casting stabilization is in 1.9m/min；
5) 38 DEG C of the first packet degree of superheat；Continuous 30 DEG C of the packet degree of superheat using M-EMS, is forbidden middle water containing opening, is drawn Speed and degree of superheat appearance are fluctuated by a relatively large margin.Continuous casting billet is 150 × 150mm2Square billet, through high speed wire rolling technique into wire rod.
Embodiment 5
Illustrate by taking spring steel 55CrSiA productions as an example：
Process for making flow：Molten iron+- 100 tons of electric furnace with eccentric bottom of high-quality steel scrap (EBT)-waiting position -100 tons of Argon station LF Refining furnace-VD stoves-continuous casting (6 machines 6 flow).
1st, electric furnace smelting process
1) strengthen the baking to ladle before tapping, ensure the red heat state of ladle liner；
2) electric furnace smelting iron and steel stock use 40% low-sulfur molten iron and 60% high-quality steel scrap, 100 tons；
3) eaf tapping point carbon content control is more than 0.15%, and the control of electric furnace steel tapping temperature is at 1660 DEG C, EBT electric furnace steel tappings Using steel is stayed to operate, it is 8% to stay steel amount, forbids tapping process slag；
4) electric furnace steel tapping progress Si/Mn al-free deoxidation techniques, addition deoxidier progress pre-deoxidation, as far as possible reduction clinker, The Al and Al that cylinder-packing, alloy etc. are brought into2O3；Active lime usage amount 360kg/ stoves, complexing agent usage amount are added in tapping process 200kg/ stoves, refining slag usage amount 380kg/ stoves.Wherein active lime：CaO 92%, S 0.06%, SiO22%, impurity 5.94%, activity degree 190；Complexing agent：SiC 21%, CaO 21%, SiO211%, TC 33%, MgO 14%；Refining slag： CaO 39%, SiO247%, A12O34%, MgO 3%, impurity 7%.
2nd, position Argon station is waited for
It is handled using BOTTOM ARGON BLOWING, it is not exposed that argon pressure and flow are subject to the top of the slag, avoids secondary oxidation and absorbs gas.
3rd, LF refining furnace technique
1) refining adds in deoxidier and active lime early period, makes the quickly de- O and de- S that higher alkalisation white slag carries out molten steel, Finished product S≤0.010% is controlled, refining basicity of slag early period is 2.2；
2) refining mid-term adds in refining slag, then adds the maintenance that deoxidier carries out clinker, reduces basicity of slag, continues to take off Oxygen desulfurization, refining later stage basicity of slag is 1.1；
3) argon gas controls：Whole BOTTOM ARGON BLOWING operation, 450~480L/min of big argon flow is used after increasing C, adduction gold early period, 0.6~0.7Mpa of pressure；Later stage composition adjustment in place, medium and small 160~180L/min of argon flow amount, pressure is used during removal of inclusions 0.15~0.28Mpa of power.
4) refining time 50min.
4th, VD techniques
1) vacuum degree is less than 67Pa during VD vacuum processings, and high vacuum keeps 15min；
2) VD breaks the adjustment for forbidding carrying out ingredient after sky again；After vacuum processing argon bottom-blowing flow control with the top of the slag not Subject to exposed, time 33min.
5th, continuous casting process
1) strengthen the baking to covering slag, tundish before casting, it is desirable that the baking of tundish time is more than 3 hours；
2) whole process protection is poured into a mould, and big packet long nozzle increases seal washer, and centre, which is unwrapped, pours packet Argon in preceding implement；
3) continuous casting is using steel operation more than big packet, tundish, using bale slag-blanking detection device, the big remaining molten steel amount 1.6 of packet Ton/stove, last 1 packet casting, 13 tons of surplus pour into tail base, scrap processing；10 stove of tundish casting sequence；
4) pulling speed of continuous casting stabilization is in 2.0m/min；
5) 33 DEG C of the first packet degree of superheat；Continuous 24 DEG C of the packet degree of superheat using M-EMS, is forbidden middle water containing opening, is drawn Speed and degree of superheat appearance are fluctuated by a relatively large margin.Continuous casting billet is 150 × 150mm2Square billet, through high speed wire rolling technique into wire rod.
The embodiment of the present invention 1, embodiment 2, embodiment 3, the finished product O content of embodiment 4 and embodiment 5, finished product S ingredients, Finished product Al content and finished product Ti contents such as the following table 1：
Table 1
Classification The trade mark Finished product O content Finished product S contents Finished product Al content Finished product Ti contents
Embodiment 1 55CrSiA 0.000698% 0.0049% 0.0027% 0.00229%
Embodiment 2 55CrSiA 0.000860% 0.0041% 0.0026% 0.00214%
Embodiment 3 55CrSiA 0.000831% 0.0046% 0.0029% 0.00207%
Embodiment 4 55CrSiA 0.000726% 0.0048% 0.0030% 0.00220%
Embodiment 5 55CrSiA 0.000912% 0.0037% 0.0026% 0.00222%
The embodiment of the present invention 1, embodiment 2, embodiment 3, embodiment 4 and embodiment 5 non-metallic inclusion according to national standard JB/T10561-1989 grading such as the following table 2：
Table 2
Classification The trade mark A (thick) A (thin) B (thick) B (thin) C (thick) C (thin) D (thick) D (thin) DS
Embodiment 1 55CrSiA 0.0 0.5 0.0 0.0 0.0 0.0 0.0 0.0 0.0
Embodiment 2 55CrSiA 0.0 0.5 0.0 0.0 0.0 0.0 0.0 0.5 0.0
Embodiment 3 55CrSiA 0.0 1.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
Embodiment 4 55CrSiA 0.0 0.5 0.0 0.0 0.0 0.0 0.0 0.0 0.5
Embodiment 5 55CrSiA 0.0 0.5 0.0 0.0 0.0 0.0 0.0 0.0 0.0

Claims (7)

1. a kind of smelting process for spring steel Control and Inclusion Removal includes the following steps：1) electric furnace just refines；2) Argon；3)LF Stove refines；4) VD stoves refine；5) continuous casting；
It is characterized in that, in step 1), electric furnace just refines the raw material using following weight percentage：35%~70% molten iron and 30%~65% steel scrap；Electric furnace uses Si/Mn al-free deoxidations technique to carry out pre-deoxidation, and use simultaneously during just producing steel Active lime, complexing agent and refining slag；
In step 3), LF stoves refinings early period using Si/Mn al-free deoxidations technique and active lime, control basicity of slag 1.5~ 2.5；LF stoves refining mid-term adds in refining slag, continues thereafter with using Si/Mn al-free deoxidation techniques, continues deoxidization desulfuration, it is ensured that stove Basicity of slag is controlled 0.7~1.4；The whole BOTTOM ARGON BLOWING of LF stoves refining；
In step 1) and step 3), refer to carry out deoxidation using ferrosilicon and ferromanganese using Si/Mn al-free deoxidation techniques.
2. the smelting process according to claim 1 for spring steel Control and Inclusion Removal, which is characterized in that in step 1), The active lime is made of the component of following weight percentage：
The complexing agent is made of the component of following weight percentage：
The refining slag is made of the component of following weight percentage：
3. the smelting process according to claim 1 for spring steel Control and Inclusion Removal, which is characterized in that in step 1), In terms of every 100 tons of raw materials, the addition of the active lime is 200~400kg, and the addition of the complexing agent is 150 ~350kg, the addition of the refining slag is 200~400kg.
4. the smelting process according to claim 1 for spring steel Control and Inclusion Removal, which is characterized in that in step 1), Electric furnace steel tapping temperature is controlled at 1620~1700 DEG C.
5. the smelting process according to claim 1 for spring steel Control and Inclusion Removal, which is characterized in that in step 1), Electric furnace uses EBT electric furnaces, and using steel, remaining slag operation technique is stayed, it is 4%~10% that the weight percentage of steel is stayed in control.
6. the smelting process according to claim 1 for spring steel Control and Inclusion Removal, which is characterized in that in step 3), The whole BOTTOM ARGON BLOWING of LF stoves refining, LF stoves first using big 400~600L/min of argon flow amount, afterwards using small argon flow amount 100~ 40~60min of 200L/min, LF stove refining time.
7. the smelting process according to claim 1 for spring steel Control and Inclusion Removal, which is characterized in that in step 4), VD treatment process vacuum degree is less than 67Pa, and high vacuum keeps 10min~20min, argon bottom-blowing flow control after vacuum processing It is not exposed that system is subject to the top of the slag, BOTTOM ARGON BLOWING time 20min~40min.
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