CN105907919A - Smelting process for control of spring steel inclusions - Google Patents

Smelting process for control of spring steel inclusions Download PDF

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Publication number
CN105907919A
CN105907919A CN201610260305.5A CN201610260305A CN105907919A CN 105907919 A CN105907919 A CN 105907919A CN 201610260305 A CN201610260305 A CN 201610260305A CN 105907919 A CN105907919 A CN 105907919A
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refining
slag
steel
stove
spring steel
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CN105907919B (en
Inventor
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 & Steel Group Co
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Hangzhou Iron & Steel Group Co
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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 smelting process for control of spring steel inclusions, wherein the smelting process includes the steps: 1) electric furnace primary smelting; 2) argon blowing; 3) LF refining; 4) VD furnace refining; and 5) continuous casting. In the electric furnace primary smelting steel-tapping process, an Si/Mn Al-free deoxidation process is adopted for pre-deoxidation, and at the same time, active lime, a compound agent and refining slag are adopted; in the earlier stage of the LF refining, an Si/Mn Al-free deoxidation process and active lime are adopted, and the furnace slag basicity is controlled at 1.5-2.5; in the middle stage of the LF refining, refined slag is added, followed by, the Si/Mn Al-free deoxidation process continues to be adopted, deoxidation and desulfuration continues to be carried out, and the furnace slag basicity is guaranteed to be controlled at 0.7-1.4; argon bottom blowing is carried out in the whole process of the LF refining. The Al-free deoxidation process and the low-basicity furnace slag desulfuration process are adopted and are combined with a specific deoxidizing agent, the inclusions in spring steel can be well controlled, and thus the anti-fatigue property of the spring steel is improved.

Description

A kind of smelting process for spring steel Control and Inclusion Removal
Technical field
The present invention relates to field of metallurgy, be specifically related to a kind of smelting process for spring steel Control and Inclusion Removal.
Background technology
Spring steel is used to manufacture spring and a special steel grade of elastic part.Along with the lightness of vehicle and energy-conservation, Road spring own wt is had higher requirement；The high speed of passenger train from goods train and heavy duty, the work being greatly increased spring is born Lotus, this it is also proposed higher requirement to the design stress of spring.Under condition of high ground stress, due to the existence of non-metallic inclusion Destroying the continuity of matrix, cause the uneven of metal structure, become the formation of crack of fatigue, the mechanical property making metal is special It not the fatigue limit decline of metal, ultimately result in the fracture of spring.There is the automobile system in Rui Mashi company of the U.S. in 2006 Dynamic device spring breakage accident, India's bridge collapse accident in 2009, praise Min overpass support fracture accident in Shanghai in 2009 Deng, all cause serious consequence.Therefore, the fatigue behaviour of spring to be improved is necessary for the nonmetal inclusion controlling well in steel Thing, the control of the non-metallic inclusion in steel has become the important research direction improving spring fatigue performance.
At present, the main enterprises that domestic and international spring steel produces has domestic Baosteel, emerging clear special steel and Nangang；External Kobe Iron company, Datong District's special steel, Thyssen company and Ipanema company.It uses the smelting flow process of spring steel Control and Inclusion Removal It is the most all: first furnace (converter or electric furnace) → refining furnace (LF+ application of vacuum) → continuous casting or molding.Wherein refinery practice is de- Oxygen is aluminium deoxidation technique mostly, uses the less of al-free deoxidation technique；Sulfur removal technology is mostly single high alkalinity slag, adopts Less with low alkalinity slag.Although the total oxygen demand of steel can be fallen below 15 × 10 by aluminium deoxidation technique effectively-6Hereinafter, but The rich aluminium zones in local easily forms larger particles deoxidation products.The high rigidity brittle inclusion corundum (Al of remaining in steel2O3) and aluminium Acid calcium (mCaO nAl2O3) adding man-hour owing to micro-crack can not will be formed with steel matrix rheology at steel billet, spring is at alternation Micro-crack extension is produced under the effect of stress, 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), use aluminium deoxidation technique.On the contrary, al-free deoxidation technique can be effectively Reduce oxygen content in steel, it is to avoid the high rigidity brittle inclusion that aluminium deoxidation technique produces.Use the sulfur removal technology of high alkalinity slag, Although the sulfur content being effectively reduced in steel, but the plastification of field trash can not be controlled well, such as document " exploitation of 60Si2Mn spring steel wire rod ".On the contrary, low alkalinity slag is used to carry out the refining of molten steel, it is possible to effectively to being mingled with Thing carries out plastification control, also can reduce the sulfur content in steel simultaneously.Therefore, al-free deoxidation technique and the desulfurization of low alkalinity slag Technique has become the priority research areas that spring steel non-metallic inclusion controls, but relevant report both domestic and external is the most little. Such as document " Si-KILLED STEEL WIRE ROD AND SPRING SUPERING IN FATIGUE CHARECTERISTIC " (application number: JP2006356308, JP2006356309, JP2006356310, JP2006356312, JP2006356313) disclose the spring Si killed steel of a kind of excellent in fatigue characteristics, and by this wire rod obtain excellent The spring of different fatigue-resistance characteristics.But it is only to the component content control range aoxidizing system field trash in special composition and wire rod Determined, be not directed to the production technology of Control and Inclusion Removal.
Application publication number is that the Chinese invention patent application of CN 104056871A (Application No. 201310681980.1) is public Open a kind of spring steel wire production technology for controlling field trash, comprised the steps: 1) carry out by al-free deoxidation technique Smelt；2) converter top bottom blowing；3) Ar station Argon processes；4) LF ladle argon-blown refining；5) application of vacuum；6) side of pouring into Base, becomes wire rod through high speed wire rolling technique.Described step 1) in, use Si/Mn to smelt the al-free deoxidation technique of spring steel 55SiCr, Control the W in molten steel[Al]＜ 47 × 10-6、a[Ca]＜ 1.5 × 10-9；Described step 2) the special ferrosilicon of middle employing, steel controls Als ＜ 0.0020%；Adding calcined magnesite ball, the addition of steel per ton is 0.5-2kg；Tapping carbon controls target 0.06～0.20wt%； Finishing slag basicity controls target R >=2.5.Although above by al-free deoxidation technique, but using the sulfur removal technology of high alkalinity slag, Although the sulfur content being effectively reduced in steel, but the plastification of field trash can not be controlled well.
Summary of the invention
The present invention is directed to technical problem present in above-mentioned prior art, it is provided that a kind of for spring steel Control and Inclusion Removal Smelting process, use al-free deoxidation technique and the sulfur removal technology of low alkalinity slag, and combine specific deoxidier etc., can be to bullet Field trash in spring steel controls well, thus improves the anti-fatigue performance of spring steel.
A kind of smelting process for spring steel Control and Inclusion Removal, comprises the following steps:
1) refine at the beginning of electric furnace；2) Argon；3) LF stove refining；4) VD stove refining；5) continuous casting；
Step 1) in, use Si/Mn al-free deoxidation technique to carry out pre-deoxidation during producing steel at the beginning of electric furnace, and use simultaneously Active lime, complexing agent and refining slag；
Step 3) in, LF stove refining early stage uses Si/Mn al-free deoxidation technique and active lime, controls basicity of slag and exists 1.5～2.5；The refining of LF stove adds refining slag mid-term, continues thereafter with employing Si/Mn al-free deoxidation technique, continues deoxidization desulfuration, really Protect basicity of slag to control 0.7～1.4；The omnidistance BOTTOM ARGON BLOWING of LF stove refining.
Following further preferred as technical solution of the present invention:
Step 1) and step 3) in, use Si/Mn al-free deoxidation technique to refer to use ferrosilicon and ferromanganese to carry out deoxidation, use The mode of precipitation desoxydation.
Step 1) in, described active lime is made up of the component of following weight percentage:
Described complexing agent is made up of the component of following weight percentage:
Described refining slag is made up of the component of following weight percentage:
Step 1) in, the raw material of the following weight percentage of refining employing at the beginning of electric furnace: molten iron (the low-sulfur iron of 35%～70% Water) and the steel scrap of 30%～65%.
In terms of every 100kg raw material, the addition of described active lime is 200～400kg, the addition of described complexing agent Amount is 150～350kg, and the addition of described refining slag is 200～400kg.
At the beginning of electric furnace, the endpoint carbon content of refining controls more than 0.15%.
Electric furnace steel tapping temperature controls at 1620～1700 DEG C.
Electric furnace uses EBT electric furnace, uses and stays steel, remaining slag operation technique, forbids tapping process slag, staying during electric furnace steel tapping In steel technique, the weight percentage controlling to stay steel is 4%～10%.
Step 2) in, wait that Argon station, position uses Bottom Argon Stirring, select suitable argon pressure and argon flow amount, with steel Water is the most exposed to be as the criterion.
Step 3) in, described active lime is made up of the component of following weight percentage:
The omnidistance BOTTOM ARGON BLOWING of LF stove refining, LF stove refining early stage uses big argon flow amount 400～600L/min, in the refining of LF stove Later stage uses little argon flow amount 100～200L/min, LF stove refining time 40～60min.
Step 4) in, VD processes technique vacuum and is less than 67Pa, and high vacuum keeps more than 10min, and (10min～20min enters One preferred 10min～15min of step), application of vacuum terminates rear argon bottom-blowing flow-control and is as the criterion, during BOTTOM ARGON BLOWING so that the top of the slag is the most exposed Between >=20min (20min～40min).
Step 5) in, strengthen covering slag, the baking of tundish before casting, it is desirable to the baking of tundish time is more than 3 hours； Whole process protection is poured into a mould, and big bag long nozzle increases seal washer, and bag Argon in implementing before watering is unwrapped in centre；Continuous casting use great Bao, in Between bag remaining steel operation, use bale slag-blanking detection device, it is ensured that the remaining 1.5 tons/stove of molten steel amount of big bag, last 1 bag casting surplus is big Water into tail base in 10 tons, scrap process；One tundish casting sequence is not more than 10 stoves；Pulling speed of continuous casting stable 1.8～ 2.4m/min, first packet molten steel overheat≤40 DEG C；The continuous bag degree of superheat≤30 DEG C, use M-EMS, forbid tundish Fluctuating by a relatively large margin occur in the mouth of a river, pulling rate and the degree of superheat.Continuous casting billet is 150 × 150mm2Square billet, becomes line through high speed wire rolling technique Material.
The smelting process of described spring steel Control and Inclusion Removal, can efficiently control the plasticity of non-metallic inclusion, reduces Non-metallic inclusion content in molten steel, the size major part of field trash can be controlled in below 5 μm.
Compared with prior art, advantages of the present invention is as follows:
One, to character, composition, the quantity of field trash phase and different requirement is distributed based on different steel grades, pin of the present invention To high Si special for spring steel 55SiCrA, high Mn feature, by controlling deoxidization technique, LF refinery practice, finally make spring steel clip Foreign material have obtained controlling well.
Two, using Si/Mn deoxidation smelting process, control Al, Ca content in steel, whole refining process does not use containing aluminium Material, decreases Al in molten steel2O3The source being mingled with Deng infusibility difficulty floating, can obtain low melting point CaO SiO2·Al2O3MgO system Plastic occluded foreignsubstance, it is to avoid form rigid harmful field trash in spring steel wire, strict control spring steel inclusion size, Quantity and distribution etc., making field trash is tiny, disperse state distribution, and inclusion morphology is conducive in spring steel wire following process Drawing, around spring etc.；The size major part of field trash can be controlled in below 5 μm simultaneously, can improve the drawing property of spring steel, increasing Add the fatigue limit of spring.
Three, electric furnace adds high-quality steel scrap with molten iron and smelts for metal charge, has not only drawn " the degassing that converter smelting is good Go to be mingled with effect " advantage, simultaneously because use electric furnace with eccentric bottom carry out staying steel tap, overcome converter smelting tap time easy The shortcoming of slag；In addition LF refining process uses double slag operation: early stage makes higher alkalisation slag, strengthens de-O, de-S dynamics, energy simultaneously Effectively controlling below 0.010% by finished product S content, decrease the source of non-metallic inclusion in molten steel, the middle and later periods makes low Basicity slag, thus improve the mobility of middle and later periods slag, floating for inclusion content in melting steel provides good dynamic conditions. Therefore use this technique to be possible not only to save hot metal pretreatment technology, reduce production cost, improve production efficiency the most also Decrease the non-metallic inclusion content in molten steel.
Detailed description of the invention
In following example, in the case of special instruction, percentage is mass percent.
Embodiment 1
Illustrate as a example by spring steel 55CrSiA produces:
Process for making flow process: molten iron+-100 tons of electric furnace with eccentric bottoms of high-quality steel scrap (EBT)-wait position-100 tons of Argon station LF Refining furnace-VD stove-continuous casting (6 machines 6 flow).
1, electric furnace smelting process
1) baking to ladle is strengthened before tapping, it is ensured that the red heat state of ladle liner；
2) electric furnace smelting iron and steel stock uses low-sulfur molten iron and the high-quality steel scrap of 60%, the 100kg of 40%；
3) eaf tapping point carbon content control is more than 0.15%, and electric furnace steel tapping temperature controls at 1640 DEG C, EBT electric furnace steel tapping Employing stays steel to operate, and staying steel amount is 6%, forbids tapping process slag；
4) electric furnace steel tapping carries out Si/Mn al-free deoxidation technique, adds deoxidier (ferrosilicon and ferromanganese) and carries out pre-deoxidation, to the greatest extent may be used Al and Al that slag, cylinder-packing, alloy etc. are brought into can be reduced2O3；Tapping process adds active lime usage amount 300kg/ stove, multiple Mixture usage amount 210kg/ stove, refining slag usage amount 350kg/ stove；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%, Al2O33%, MgO 4%, impurity 7%.
2, Argon station, position is waited
Employing BOTTOM ARGON BLOWING processes, and argon pressure and flow are as the criterion so that the top of the slag is the most exposed, it is to avoid secondary oxidation and absorption gas.
3, LF refining furnace technique
1) refining early stage adds deoxidier (ferrosilicon and ferromanganese) and active lime, makes higher alkalisation white slag and carries out the fast of molten steel De-O and the de-S of speed, controls finished product S≤0.010%, and refining early stage basicity of slag is 1.5；
2) refining adds refining slag mid-term, adds deoxidier subsequently and carries out the maintenance of slag, reduces basicity of slag, continues de- Oxygen desulfurization, refining later stage basicity of slag is 1.2；
3) argon gas controls: omnidistance BOTTOM ARGON BLOWING operation, early stage increases C, add alloy after use big argon flow 500L/min, pressure 0.65～0.75Mpa；Later stage composition adjustment puts in place, uses medium and small argon flow amount 150L/min, pressure 0.20 during removal of inclusions ～0.25Mpa.
4) refining time 50min.
4, VD technique
1) during VD application of vacuum, vacuum keeps 12min less than 67Pa, high vacuum；
2) forbid carrying out again the adjustment of composition after VD breaks sky；Application of vacuum terminates rear argon bottom-blowing flow-control with the top of the slag not Exposed it is as the criterion, time 25min.
5, continuous casting process
1) strengthen covering slag, the baking of tundish before casting, it is desirable to 4 hours baking of tundish time；
2) whole process protection cast, big bag long nozzle increases seal washer, and bag Argon in implementing before watering is unwrapped in centre；
3) continuous casting uses steel operation more than big bag, tundish, uses bale slag-blanking detection device, the remaining molten steel amount 1.7 of big bag Ton/stove, last 1 bag casting surplus 11 tons is watered into tail base, is scrapped process；Tundish casting sequence 10 stove；
4) pulling speed of continuous casting is stable at 2.0m/min；
5) the first packet degree of superheat 36 DEG C；The continuous bag degree of superheat 25 DEG C, uses M-EMS, forbid middle water containing opening, draw Fluctuating by a relatively large margin occur in speed and the degree of superheat.Continuous casting billet is 150 × 150mm2Square billet, becomes wire rod through high speed wire rolling technique.
Embodiment 2
Illustrate as a example by spring steel 55CrSiA produces:
Process for making flow process: molten iron+-100 tons of electric furnace with eccentric bottoms of high-quality steel scrap (EBT)-wait position-100 tons of Argon station LF Refining furnace-VD stove-continuous casting (6 machines 6 flow).
1, electric furnace smelting process
1) baking to ladle is strengthened before tapping, it is ensured that the red heat state of ladle liner；
2) electric furnace smelting iron and steel stock uses low-sulfur molten iron and the high-quality steel scrap of 55%, the 100kg of 45%；
3) eaf tapping point carbon content control is more than 0.15%, and electric furnace steel tapping temperature controls at 1660 DEG C, EBT electric furnace steel tapping Employing stays steel to operate, and staying steel amount is 8%, forbids tapping process slag；
4) electric furnace steel tapping carries out Si/Mn al-free deoxidation technique, adds deoxidier and carries out pre-deoxidation, reduce as far as possible slag, Al and Al that cylinder-packing, alloy etc. are brought into2O3；Tapping process adds active lime usage amount 270kg/ stove, complexing agent usage amount 230kg/ stove, refining slag usage amount 340kg/ stove.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%, Al2O34%, MgO 3%, impurity 7%.
2, Argon station, position is waited
Employing BOTTOM ARGON BLOWING processes, and argon pressure and flow are as the criterion so that the top of the slag is the most exposed, it is to avoid secondary oxidation and absorption gas.
3, LF refining furnace technique
1) refining early stage adds deoxidier and active lime, makes higher alkalisation white slag and carries out the most de-O and the de-S of molten steel, Controlling finished product S≤0.010%, refining early stage basicity of slag is 2.3；
2) refining adds refining slag mid-term, adds deoxidier subsequently and carries out the maintenance of slag, reduces basicity of slag, continues de- Oxygen desulfurization, refining later stage basicity of slag is 1.4；
3) argon gas controls: omnidistance BOTTOM ARGON BLOWING operation, early stage increases C, add alloy after use big argon flow 550L/min, pressure 0.65～0.80Mpa；Later stage composition adjustment puts in place, uses medium and small argon flow amount 125L/min, pressure 0.20 during removal of inclusions ～0.30Mpa.
4) refining time 45min.
4, VD technique
1) during VD application of vacuum, vacuum keeps 14min less than 67Pa, high vacuum；
2) forbid carrying out again the adjustment of composition after VD breaks sky；Application of vacuum terminates rear argon bottom-blowing flow-control with the top of the slag not Exposed it is as the criterion, time 28min.
5, continuous casting process
1) strengthen covering slag, the baking of tundish before casting, it is desirable to the baking of tundish time is more than 3 hours；
2) whole process protection cast, big bag long nozzle increases seal washer, and bag Argon in implementing before watering is unwrapped in centre；
3) continuous casting uses steel operation more than big bag, tundish, uses bale slag-blanking detection device, the remaining molten steel amount 1.8 of big bag Ton/stove, last 1 bag casting surplus 13 tons is watered into tail base, is scrapped process；Tundish casting sequence 10 stove；
4) pulling speed of continuous casting is stable at 2.1m/min；
5) the first packet degree of superheat 35 DEG C；The continuous bag degree of superheat 30 DEG C, uses M-EMS, forbid middle water containing opening, draw Fluctuating by a relatively large margin occur in speed and the degree of superheat.Continuous casting billet is 150 × 150mm2Square billet, becomes wire rod through high speed wire rolling technique.
Embodiment 3
Illustrate as a example by spring steel 55CrSiA produces:
Process for making flow process: molten iron+-100 tons of electric furnace with eccentric bottoms of high-quality steel scrap (EBT)-wait position-100 tons of Argon station LF Refining furnace-VD stove-continuous casting (6 machines 6 flow).
1, electric furnace smelting process
1) baking to ladle is strengthened before tapping, it is ensured that the red heat state of ladle liner；
2) electric furnace smelting iron and steel stock uses low-sulfur molten iron and the high-quality steel scrap of 55%, the 100kg of 45%；
3) eaf tapping point carbon content control is more than 0.15%, and electric furnace steel tapping temperature controls at 1680 DEG C, EBT electric furnace steel tapping Employing stays steel to operate, and staying steel amount is 7%, forbids tapping process slag；
4) electric furnace steel tapping carries out Si/Mn al-free deoxidation technique, adds deoxidier and carries out pre-deoxidation, reduce as far as possible slag, Al and Al that cylinder-packing, alloy etc. are brought into2O3；Tapping process adds active lime usage amount 270kg/ stove, complexing agent usage amount 280kg/ stove, refining slag usage amount 240kg/ stove.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%, Al2O34%, MgO 3%, impurity 7%.
2, Argon station, position is waited
Employing BOTTOM ARGON BLOWING processes, and argon pressure and flow are as the criterion so that the top of the slag is the most exposed, it is to avoid secondary oxidation and absorption gas.
3, LF refining furnace technique
1) refining early stage adds deoxidier and active lime, makes higher alkalisation white slag and carries out the most de-O and the de-S of molten steel, Controlling finished product S≤0.010%, refining early stage basicity of slag is 1.9；
2) refining adds refining slag mid-term, adds deoxidier subsequently and carries out the maintenance of slag, reduces basicity of slag, continues de- Oxygen desulfurization, refining later stage basicity of slag is 1.1；
3) argon gas controls: omnidistance BOTTOM ARGON BLOWING operation, early stage increases C, add alloy after use big argon flow 450L/min, pressure 0.65～0.75Mpa；Later stage composition adjustment puts in place, uses medium and small argon flow amount 130L/min, pressure 0.20 during removal of inclusions ～0.25Mpa.
4) refining time 60min.
4, VD technique
1) during VD application of vacuum, vacuum keeps 15min less than 67Pa, high vacuum；
2) forbid carrying out again the adjustment of composition after VD breaks sky；Application of vacuum terminates rear argon bottom-blowing flow-control with the top of the slag not Exposed it is as the criterion, time 35min.
5, continuous casting process
1) strengthen covering slag, the baking of tundish before casting, it is desirable to the baking of tundish time is more than 3 hours；
2) whole process protection cast, big bag long nozzle increases seal washer, and bag Argon in implementing before watering is unwrapped in centre；
3) continuous casting uses steel operation more than big bag, tundish, uses bale slag-blanking detection device, the remaining molten steel amount 1.5 of big bag Ton/stove, last 1 bag casting surplus 11 tons is watered into tail base, is scrapped process；Tundish casting sequence 10 stove；
4) pulling speed of continuous casting is stable at 2.1m/min；
5) the first packet degree of superheat 38 DEG C；The continuous bag degree of superheat 27 DEG C, uses M-EMS, forbid middle water containing opening, draw Fluctuating by a relatively large margin occur in speed and the degree of superheat.Continuous casting billet is 150 × 150mm2Square billet, becomes wire rod through high speed wire rolling technique.
Embodiment 4
Illustrate as a example by spring steel 55CrSiA produces:
Process for making flow process: molten iron+-100 tons of electric furnace with eccentric bottoms of high-quality steel scrap (EBT)-wait position-100 tons of Argon station LF Refining furnace-VD stove-continuous casting (6 machines 6 flow).
1, electric furnace smelting process
1) baking to ladle is strengthened before tapping, it is ensured that the red heat state of ladle liner；
2) electric furnace smelting iron and steel stock uses low-sulfur molten iron and the high-quality steel scrap of 50%, the 100kg of 50%；
3) eaf tapping point carbon content control is more than 0.15%, and electric furnace steel tapping temperature controls at 1670 DEG C, EBT electric furnace steel tapping Employing stays steel to operate, and staying steel amount is 8%, forbids tapping process slag；
4) electric furnace steel tapping carries out Si/Mn al-free deoxidation technique, adds deoxidier and carries out pre-deoxidation, reduce as far as possible slag, Al and Al that cylinder-packing, alloy etc. are brought into2O3；Tapping process adds active lime usage amount 290kg/ stove, complexing agent usage amount 200kg/ stove, refining slag usage amount 350kg/ stove.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%, Al2O33%, MgO 4%, impurity 7%.
2, Argon station, position is waited
Employing BOTTOM ARGON BLOWING processes, and argon pressure and flow are as the criterion so that the top of the slag is the most exposed, it is to avoid secondary oxidation and absorption gas.
3, LF refining furnace technique
1) refining early stage adds deoxidier and active lime, makes higher alkalisation white slag and carries out the most de-O and the de-S of molten steel, Controlling finished product S≤0.010%, refining early stage basicity of slag is 1.7；
2) refining adds refining slag mid-term, adds deoxidier subsequently and carries out the maintenance of slag, reduces basicity of slag, continues de- Oxygen desulfurization, refining later stage basicity of slag is 0.9；
3) argon gas controls: omnidistance BOTTOM ARGON BLOWING operation, early stage increases C, add alloy after use big argon flow 420～450L/min, Pressure 0.6～0.8Mpa；Later stage composition adjustment puts in place, uses medium and small argon flow amount 110～140L/min during removal of inclusions, pressure Power 0.20～0.30Mpa.
4) refining time 55min.
4, VD technique
1) during VD application of vacuum, vacuum keeps 10min less than 67Pa, high vacuum；
2) forbid carrying out again the adjustment of composition after VD breaks sky；Application of vacuum terminates rear argon bottom-blowing flow-control with the top of the slag not Exposed it is as the criterion, time 33min.
5, continuous casting process
1) strengthen covering slag, the baking of tundish before casting, it is desirable to the baking of tundish time is more than 3 hours；
2) whole process protection cast, big bag long nozzle increases seal washer, and bag Argon in implementing before watering is unwrapped in centre；
3) continuous casting uses steel operation more than big bag, tundish, uses bale slag-blanking detection device, the remaining molten steel amount 1.8 of big bag Ton/stove, last 1 bag casting surplus 12 tons is watered into tail base, is scrapped process；Tundish casting sequence 10 stove；
4) pulling speed of continuous casting is stable at 1.9m/min；
5) the first packet degree of superheat 38 DEG C；The continuous bag degree of superheat 30 DEG C, uses M-EMS, forbid middle water containing opening, draw Fluctuating by a relatively large margin occur in speed and the degree of superheat.Continuous casting billet is 150 × 150mm2Square billet, becomes wire rod through high speed wire rolling technique.
Embodiment 5
Illustrate as a example by spring steel 55CrSiA produces:
Process for making flow process: molten iron+-100 tons of electric furnace with eccentric bottoms of high-quality steel scrap (EBT)-wait position-100 tons of Argon station LF Refining furnace-VD stove-continuous casting (6 machines 6 flow).
1, electric furnace smelting process
1) baking to ladle is strengthened before tapping, it is ensured that the red heat state of ladle liner；
2) electric furnace smelting iron and steel stock uses low-sulfur molten iron and the high-quality steel scrap of 60%, the 100kg of 40%；
3) eaf tapping point carbon content control is more than 0.15%, and electric furnace steel tapping temperature controls at 1660 DEG C, EBT electric furnace steel tapping Employing stays steel to operate, and staying steel amount is 8%, forbids tapping process slag；
4) electric furnace steel tapping carries out Si/Mn al-free deoxidation technique, adds deoxidier and carries out pre-deoxidation, reduce as far as possible slag, Al and Al that cylinder-packing, alloy etc. are brought into2O3；Tapping process adds active lime usage amount 360kg/ stove, complexing agent usage amount 200kg/ stove, refining slag usage amount 380kg/ stove.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%, Al2O34%, MgO 3%, impurity 7%.
2, Argon station, position is waited
Employing BOTTOM ARGON BLOWING processes, and argon pressure and flow are as the criterion so that the top of the slag is the most exposed, it is to avoid secondary oxidation and absorption gas.
3, LF refining furnace technique
1) refining early stage adds deoxidier and active lime, makes higher alkalisation white slag and carries out the most de-O and the de-S of molten steel, Controlling finished product S≤0.010%, refining early stage basicity of slag is 2.2；
2) refining adds refining slag mid-term, adds deoxidier subsequently and carries out the maintenance of slag, reduces basicity of slag, continues de- Oxygen desulfurization, refining later stage basicity of slag is 1.1；
3) argon gas controls: omnidistance BOTTOM ARGON BLOWING operation, early stage increases C, add alloy after use big argon flow 450～480L/min, Pressure 0.6～0.7Mpa；Later stage composition adjustment puts in place, uses medium and small argon flow amount 160～180L/min during removal of inclusions, pressure Power 0.15～0.28Mpa.
4) refining time 50min.
4, VD technique
1) during VD application of vacuum, vacuum keeps 15min less than 67Pa, high vacuum；
2) forbid carrying out again the adjustment of composition after VD breaks sky；Application of vacuum terminates rear argon bottom-blowing flow-control with the top of the slag not Exposed it is as the criterion, time 33min.
5, continuous casting process
1) strengthen covering slag, the baking of tundish before casting, it is desirable to the baking of tundish time is more than 3 hours；
2) whole process protection cast, big bag long nozzle increases seal washer, and bag Argon in implementing before watering is unwrapped in centre；
3) continuous casting uses steel operation more than big bag, tundish, uses bale slag-blanking detection device, the remaining molten steel amount 1.6 of big bag Ton/stove, last 1 bag casting surplus 13 tons is watered into tail base, is scrapped process；Tundish casting sequence 10 stove；
4) pulling speed of continuous casting is stable at 2.0m/min；
5) the first packet degree of superheat 33 DEG C；The continuous bag degree of superheat 24 DEG C, uses M-EMS, forbid middle water containing opening, draw Fluctuating by a relatively large margin occur in speed and the degree of superheat.Continuous casting billet is 150 × 150mm2Square billet, becomes wire rod through high speed wire rolling technique.
The finished product O content of the embodiment of the present invention 1, embodiment 2, embodiment 3, embodiment 4 and embodiment 5, finished product S composition, Finished product Al content and finished product Ti content such as table 1 below:
Table 1
Classification The trade mark Finished product O content Finished product S content Finished product Al content Finished product Ti content
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 non-metallic inclusion of the embodiment of the present invention 1, embodiment 2, embodiment 3, embodiment 4 and embodiment 5 is according to GB JB/T10561-1989 grades such as table 2 below:
Table 2
Classification The trade mark A (slightly) A (carefully) B (slightly) B (carefully) C (slightly) C (carefully) D (slightly) D (carefully) 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 (9)

1., for the smelting process of spring steel Control and Inclusion Removal, comprise the following steps: 1) refine at the beginning of electric furnace；2) Argon；3)LF Stove refines；4) VD stove refining；5) continuous casting；
It is characterized in that, step 1) in, use Si/Mn al-free deoxidation technique to carry out pre-deoxidation during producing steel at the beginning of electric furnace, and Use active lime, complexing agent and refining slag simultaneously；
Step 3) in, LF stove refining early stage uses Si/Mn al-free deoxidation technique and active lime, control basicity of slag 1.5～ 2.5；The refining of LF stove adds refining slag mid-term, continues thereafter with employing Si/Mn al-free deoxidation technique, continues deoxidization desulfuration, it is ensured that stove Basicity of slag controls 0.7～1.4；The omnidistance BOTTOM ARGON BLOWING of LF stove refining.
Smelting process for spring steel Control and Inclusion Removal the most according to claim 1, it is characterised in that step 1) and step Rapid 3), in, Si/Mn al-free deoxidation technique is used to refer to use ferrosilicon and ferromanganese to carry out deoxidation.
Smelting process for spring steel Control and Inclusion Removal the most according to claim 1, it is characterised in that step 1) in, Described active lime is made up of the component of following weight percentage:
Described complexing agent is made up of the component of following weight percentage:
Described refining slag is made up of the component of following weight percentage:
Smelting process for spring steel Control and Inclusion Removal the most according to claim 1, it is characterised in that step 1) in, The raw material of the following weight percentage of refining employing at the beginning of electric furnace: the molten iron of 35%～70% and 30%～the steel scrap of 65%.
Smelting process for spring steel Control and Inclusion Removal the most according to claim 4, it is characterised in that step 1) in, In terms of every 100kg raw material, the addition of described active lime is 200～400kg, and the addition of described complexing agent is 150 ～350kg, the addition of described refining slag is 200～400kg.
Smelting process for spring steel Control and Inclusion Removal the most according to claim 1, it is characterised in that step 1) in, Electric furnace steel tapping temperature controls at 1620～1700 DEG C.
Smelting process for spring steel Control and Inclusion Removal the most according to claim 1, it is characterised in that step 1) in, Electric furnace uses EBT electric furnace, uses and stays steel, remaining slag operation technique, and the weight percentage controlling to stay steel is 4%～10%.
Smelting process for spring steel Control and Inclusion Removal the most according to claim 1, it is characterised in that step 3) in, The omnidistance BOTTOM ARGON BLOWING of LF stove refining, LF stove first uses big argon flow amount 400～600L/min, rear use little argon flow amount 100～ 200L/min, LF stove refining time 40～60min.
Smelting process for spring steel Control and Inclusion Removal the most according to claim 1, it is characterised in that step 4) in, VD processes technique vacuum and keeps 10min～20min less than 67Pa, high vacuum, and application of vacuum terminates rear argon bottom-blowing flow control System is as the criterion so that the top of the slag is the most exposed, BOTTOM ARGON BLOWING time 20min～40min.
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CN107739779A (en) * 2017-11-24 2018-02-27 马鞍山钢铁股份有限公司 A kind of method using VD carbon deoxygenation refining spring steel
CN107739779B (en) * 2017-11-24 2019-11-12 马鞍山钢铁股份有限公司 A method of utilizing VD carbon deoxygenation refining spring steel
CN108715912A (en) * 2018-06-07 2018-10-30 舞阳钢铁有限责任公司 A kind of method of electric furnace smelting low nitrogen steel
CN109295275A (en) * 2018-10-28 2019-02-01 石钢京诚装备技术有限公司 A kind of 18Cr2Ni4W high alloy carburation steel and its production method
CN112442572A (en) * 2019-08-30 2021-03-05 宝山钢铁股份有限公司 Deoxidation control method for high-end bearing steel inclusion
CN112029958A (en) * 2020-08-14 2020-12-04 北京科技大学 High-quality spring steel and refining method thereof
CN113061799A (en) * 2021-03-30 2021-07-02 张家港荣盛特钢有限公司 High-cleanliness spring steel and production method thereof
CN113061799B (en) * 2021-03-30 2022-07-22 张家港荣盛特钢有限公司 High-cleanliness spring steel and production method thereof
CN113528757A (en) * 2021-06-24 2021-10-22 山东钢铁股份有限公司 Ladle refining slag and smelting method thereof
CN115537671A (en) * 2021-06-30 2022-12-30 宝山钢铁股份有限公司 Preparation method of valve spring steel
CN115537671B (en) * 2021-06-30 2023-09-12 宝山钢铁股份有限公司 Preparation method of valve spring steel
CN113699303A (en) * 2021-09-02 2021-11-26 广东韶钢松山股份有限公司 Smelting method for steel for automobile suspension spring
CN113699303B (en) * 2021-09-02 2022-12-06 广东韶钢松山股份有限公司 Smelting method for steel for automobile suspension spring
CN114427016A (en) * 2022-01-29 2022-05-03 中天钢铁集团有限公司 Production method of aluminum-free bearing steel
CN116254387A (en) * 2023-03-13 2023-06-13 丽水华宏钢铁制品有限公司 Smelting method for producing steel for cord from pure scrap steel of electric furnace

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