CN105331769B - Deep-drawing pure iron for high-strength fastening piece and production method of deep-drawing pure iron - Google Patents

Deep-drawing pure iron for high-strength fastening piece and production method of deep-drawing pure iron Download PDF

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Publication number
CN105331769B
CN105331769B CN201510630796.3A CN201510630796A CN105331769B CN 105331769 B CN105331769 B CN 105331769B CN 201510630796 A CN201510630796 A CN 201510630796A CN 105331769 B CN105331769 B CN 105331769B
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deep
pure iron
production method
controlled
rolling
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CN105331769A (en
Inventor
戴永刚
田新中
张治广
姜国鹏
张素萍
李宝秀
阮士朋
黄翠环
宋云霞
李世琳
郭明仪
李永超
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Xingtai Iron and Steel Co Ltd
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Xingtai Iron and Steel Co Ltd
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    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/14—Ferrous alloys, e.g. steel alloys containing titanium or zirconium
    • 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
    • C21C7/0006—Adding metallic additives
    • 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
    • C21C7/0025—Adding carbon material
    • 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
    • C21C7/0037—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00 by injecting powdered material
    • 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
    • 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
    • C21C7/068—Decarburising
    • 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
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/06—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of rods or wires
    • C21D8/065—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of rods or wires of ferrous alloys
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D2211/00—Microstructure comprising significant phases
    • C21D2211/005—Ferrite

Abstract

The invention discloses deep-drawing pure iron for a high-strength fastening piece and a production method of the deep-drawing pure iron. The deep-drawing pure iron comprises, by mass, 0.015%-0.025% of C, not larger than 0.03% of Si, not larger than 0.15% of Mn, 0.06%-0.08% of Ti, 0.03%-0.05% of Al, not larger than 0.015% of P, not larger than 0.015% of S and the balance Fe and inevitable impurities. The production method includes the steps that blast furnace molten iron is subjected to converter smelting, LF furnace refining, RH furnace refining, continuous casting, controlled rolling and controlled cooling and coil collection, and the deep-drawing pure iron is obtained. According to the deep-drawing pure iron and the production method, a pure iron coil rod which is low in production cost and high in strength and is used for deep drawing is produced through an existing refining process and the controlled rolling and controlled cooling process, the produced hot-rolled coil rod can meet the requirements that tensile strength reaches 340+/-20 Mpa and one third of cold-headed products are qualified, and the requirement for high-strength fasting pieces of furniture production of downstream enterprises is met.

Description

A kind of high-intensity fasteners deep-draw pure iron and its production method
Technical field
The invention belongs to technical field of steel production, is related to a kind of high-intensity fasteners deep-draw pure iron and its producer Method.
Background technology
Deep-draw pure iron is mainly characterized in that material is soft, plasticity is good, not easy to crack in big distortion.It is generally used for production The larger rivet processing of deflection, its strength of parent requirement is relatively low, plays attractive, decorative, the effect of low-intensity anchoring, extensively should Used in aspects such as case and bag, perambulator, tables and chairs.
Deep-draw pure iron typically requires the cold heading performance of wire rod mother metal, and strength of parent is not required, pure according to normal control The intensity of iron only has 280Mpa or so.But in the recent period down-stream enterprise proposes a kind of securing member pure iron demand of furniture application, wherein Propose that, using the production of Φ 6.5mm specifications wire rod, wire rod strength of parent need to meet the qualified demand of 340 ± 20Mpa, cold upsetting 1/3. User has found to be unable to reach both meet tensile strength using domestic wire rod, but also with the requirement of aximal deformation value, and according to import Material, user cost can increase, while the stability of the source of goods cannot be ensured, therefore need domestic steel mill's exploitation new material satisfaction badly Its needs.
The use requirement of user is analyzed for this, it claims to wire rod mother metal performance and mainly have：Tensile strength is 340 ± 20Mpa, cold upsetting 1/3 is qualified；The intensity belongs to high intensity control range in pure iron steel grade category, and normal pure iron can not reach High intensity so.Therefore our specific aims are analyzed the pure iron material, and from composition, Control and Inclusion Removal, controlled rolling control The aspects such as cold, metallographic structure have carried out design optimization to steel grade.Pure iron steel grade technique is typically using the work of converter-RH stoves-continuous casting Skill, Xing Gang employs converter-LF stoves-RH stoves-continuous casting-cogging-controlled rolling and controlled cooling according to the rational stitch technique route of existing equipment The process route become a useful person of the fire of fine work steel two, develop High-strength pure iron pan bar, meet down-stream enterprise's tensile strength for 340 ± The deep-draw pure iron steel grade demand of 20Mpa.
The content of the invention
The present invention seeks to strong using the process route production tension of converter, LF stoves, RH stoves, continuous casting, cogging, controlled rolling and controlled cooling Spend for 340 ± 20Mpa, the qualified deep-draw pure iron class wire rod of cold upsetting 1/3 so as to possess and be easy to drawing and intensity is higher, plasticity is good Good wire rod product, meets user for the demand in terms of pure iron securing member.
To solve above-mentioned technical problem, the present invention is adopted the following technical scheme that：A kind of high-intensity fasteners deep-draw pure iron, The deep-draw pure iron chemical composition mass percent is as follows：C：0.015～0.025%, Si≤0.03%, Mn≤0.15%, Ti： 0.06～0.08%, Al:0.03-0.05%, P≤0.015%, S≤0.015%, balance of Fe and inevitable impurity.
A kind of high-intensity fasteners production method of deep-draw pure iron, it is blast-melted through converter smelting, the refining of LF stoves, RH Stove refining, continuous casting, controlled rolling and controlled cooling, collection volume operation, obtain the deep-draw pure iron, and specific embodiment is as follows：
（1）Converter smelting：It is blast-melted to carry out after desulfurization process, combined blown converter smelting is blended into, add aluminium block to take off after tapping Oxygen, top slag adds lime 2.0-3.5kg/T；
（2）LF stoves are refined：After LF enters the station, slag charge addition is as follows：Lime 2.0-4.0kg/T, and using calcium carbide, aluminum shot Slag making；And be warming up to 1650～1680 DEG C, top slag color based on white or light green, FeO and MnO quality sums in slag≤ 1.0%, molten steel oxygen≤50ppm leaving from station；
（3）RH stoves are refined：Molten steel is hung to into RH stoves, forvacuum simultaneously carries out oxygen blast pressure Decarburization Operation, forces in oxygen blast Carbonization treatment is finished, and using aluminum shot deoxidation, adds carbon dust 0.15-0.20kg/t, ferrotianium 1.3-1.6kg/t to carry out alloying component tune It is whole；
（4）Continuous casting：RH stoves, it is leaving from station before carry out after Calcium treatment and soft blow 8min, being hung to conticaster and being cast into bloom；
The mass percent of composition in middle Baogang's water：C：0.015～0.025%, Si≤0.03%, Mn≤0.15%, Ti： 0.06～0.08%, Al:0.03-0.05%, P≤0.015%, S≤0.015%, balance of Fe and inevitable impurity；
（5）Controlled rolling and controlled cooling：After bloom cogging, 1070～1090 DEG C are warming up to into heating furnace, steel billet of coming out of the stove carries out height Pressure water dephosphorization, into fast mill rolling；The operation of rolling enters final rolling temperature for 880 ± 15 DEG C, and laying temperature is 910 ± 10 DEG C, Again Jing collection volume operation, obtains the deep-draw pure iron.
Step of the present invention（5）In controlled rolling and controlled cooling operation, the steel billet after rolling enters Stelmor cooling line, adjusts wind Cold line stay-warm case opens quantity and blower fan aperture, and wire rod phase transformation leading portion cooldown rate is 1.5～2.0 DEG C/s after spinning.
Step of the present invention（3）In RH stove refining procedures, the forvacuum is simultaneously carried out in oxygen blast pressure decarburization, control Parameter is：Remaining oxygen is controlled in 300-450ppm；After aluminum shot deoxidation, Oxygen Content in Liquid Steel≤15ppm leaving from station is controlled.
Step of the present invention（3）In RH stove refining procedures, after oxygen blast forces Decarburization Operation to terminate, using full pumping vacuum Process, vacuum≤150pa, control decarburization circulation time 10-15min.
Step of the present invention（3）In RH stove refining procedures, the addition carbon dust, ferrotianium carry out alloying component adjustment, make Obtain C in molten steel：0.015～0.025%, Ti：0.06～0.08%；Simultaneously Calcium treatment leaving from station, controls Ca：25-45ppm.
Step of the present invention（3）In RH stove refining procedures, the RH circulation times 10-15min.
Step of the present invention（1）In converter smelting operation, blast-melted middle S≤0.013%.
Step of the present invention（4）In continuous casting working procedure, the bloom specification is 325 × 280mm2。
Step of the present invention（5）In controlled rolling and controlled cooling operation, the bloom cogging is into 160 × 160mm2Specification
The technology of the present invention principle is as follows：1st, pure iron steel grade due to whole compositions it is relatively low, wire rod tissue is entirely ferrite, difficult To adjust mechanical property separately through controlled rolling and controlled cooling means.Therefore need to increase solution strengthening element C, while user requires necessarily Strength range, has carried out vernier control interval 0.015～0.025% in steel grade to C element.
2nd, to meet user's deep drawability needs, using tissue is improved, deformation method for grain refinement improves wire rod performance, crystal grain Refinement increases number of grain boundaries, and crystal boundary is the obstacle of dislocation motion, and crystal boundary can be being limited to certain model plastic deformation In enclosing, homogenize deformation, crystal boundary is also the resistance of Crack Extension, and crystal grain is thinner, and crack propagation critical stress is bigger, material Toughness is better.
Add Ti elements in steel grade first, tiny dystectic Ti type impurities are produced in molten steel, so as to process of setting Promote ferrite IGF nucleation rates, play a part of induced nucleation, reach effectively segmentation crystal grain, the purpose of thinning microstructure.
Secondly TiN pinning crystal boundaries are utilized, the crystal grain after effectively suppressing recrystallization and recrystallizing is grown up, and realizes raw material Crystal grain refinement and phase transformation strengthening, improve wire rod intensity also improves plasticity simultaneously.
Simultaneously in rolling link using adjustment rolling line cooling controlling and rolling controlling process, zerolling is realized, control material grains degree is long Greatly, crystal grain has been refined.
3rd, it is the addition of guarantee steel grade Ti elements, LF stoves are effectively reduced using the top Slag treatment mode of complete deoxidation Ti alloys are lost, while deoxidation products Al2O3 in Calcium treatment and soft blow, with steel is carried out before RH stoves are leaving from station forms low melting point inclususions Thing, it is to avoid mouth of a river wadding stream affects in casting cycle.
Mentality of designing of the present invention is as follows：1st, initially with itself peculiar technological process：Blast-melted-converter-LF stove-RH Stove-large square bland continuous-casting machine-heating furnace-cogging-heating furnace-water under high pressure dephosphorization-high-speed rolling-collection volume.
2nd, for steel grade intensity, pure iron steel grade C Composition Control scopes are improve, is heated up by LF stoves and good top slag changes System process, in RH stoves molten steel alloying component adjustment is carried out, while ensureing that deoxidation of molten steel is good, is reduced in steel by RH circulation and is harmful to Field trash.
3rd, in order to improve the cold heading performance of material, the RH stove later stages add Ti elements, produce tiny dystectic Ti classes folder Debris, so as to promote ferrite IGF nucleation rates, play a part of induced nucleation, reach effectively segmentation crystal grain, the mesh of thinning microstructure 's.
Simultaneously in rolling link using adjustment rolling line cooling controlling and rolling controlling process, using TiN pinning crystal boundaries, effectively suppress to tie again Crystal grain after brilliant and recrystallization is grown up, and realizes the crystal grain refinement and phase transformation strengthening of raw material, and improve wire rod intensity also improves simultaneously Plasticity.
4th, zerolling is realized using adjustment rolling line cooling controlling and rolling controlling process in rolling link, is reached in terms of temperature control To the purpose that control material grains degree is grown up.
It is using the beneficial effect produced by above-mentioned technical proposal：It is raw using existing refinery practice, cooling controlling and rolling controlling process Produce low cost, the deep-draw of high intensity pure iron wire rod, the rolled wire rod tensile strength of invention production up to 340 ± 20Mpa, Cold upsetting 1/3 is qualified, while the demand that down-stream enterprise produces furniture high-intensity fasteners can be met.
Description of the drawings
Fig. 1 is normal pure iron steel grade grain size micro-structure diagram；
Fig. 2 is the micro-structure diagram of deep-draw pure iron crystal grain thinning.
Specific embodiment
With reference to specific embodiment and accompanying drawing, the present invention is further detailed explanation.
Embodiment 1
Deep-draw pure iron chemical composition mass percent is as follows：C：0.025%, Si：0.03%, Mn：0.15%, Ti：0.08%, Al：0.04%, P：0.015%, S：0.015%, balance of Fe and inevitable impurity.
Production technology is as follows：
（1）Blast-melted to be blended into converter smelting, tapping adds aluminium block deoxidation, later stage to add lime 2.0kg/T.
（2）After LF enters the station, top slag adds lime 2.0kg/T, and using calcium carbide, aluminum shot slag making；And it is warming up to 1650 DEG C, Top slag is white, in slag（FeO+MnO）For 1.0%, molten steel oxygen 50ppm leaving from station.
（3）Molten steel is hung to into RH stoves, forvacuum simultaneously carries out OB operations（Decarburization is forced in oxygen blast）, it is true using full pumping after OB Vacancy is managed, and controls vacuum 150pa；After OB terminates, decarburization circulation time 8min is controlled, decarburization terminates to determine oxygen, remaining oxygen control In 300ppm, and aluminum shot deoxidation is used according to oxygen value is determined, add carbon dust, ferrotianium to carry out alloying component adjustment, RH circulation after deoxidation Time 10min.
（4）RH stoves Oxygen Content in Liquid Steel leaving from station is 15ppm, it is leaving from station before carry out Calcium treatment, molten steel Ca is controlled in 25ppm, soft blow After 8min, conticaster casting is hung to.The mass percent of composition in middle Baogang's water：C：0.025%, Si：0.03%, Mn：0.15%, Ti：0.08%, Al：0.04%, P：0.015%, S：0.015%, balance of Fe and inevitable impurity.
（5）After bloom cogging, 1090 DEG C are warming up to into heating furnace, steel billet of coming out of the stove carries out water under high pressure dephosphorization, into height Fast mill milling.The operation of rolling enters final rolling temperature control at 895 DEG C, and laying temperature is controlled at 920 DEG C.
Into Stelmor cooling line, adjust air-cooled line stay-warm case and open quantity and blower fan aperture, wire rod phase transformation after spinning Leading portion cooldown rate is controlled in 2.0 DEG C/s.
The deep-draw pure iron tensile strength for obtaining is 360Mpa, and cold upsetting 1/3 is qualified.
Embodiment 2
Deep-draw pure iron chemical composition mass percent is as follows：C：0.015%, Si：0.02%, Mn：0.12%, Ti：0.06%, Al：0.03%, P：0.012%, S：0.010%, balance of Fe and inevitable impurity.
Production technology is as follows：
（1）Blast-melted to be blended into converter smelting, tapping adds aluminium block deoxidation, later stage to add lime 3.5kg/T.
（2）After LF enters the station, top slag adds lime 4.0kg/T, and using calcium carbide, aluminum shot slag making；And it is warming up to 1680 DEG C, Top slag color is light green, in slag（FeO+MnO）For 0.95%, molten steel oxygen leaving from station is 35ppm.
（3）Molten steel is hung to into RH stoves, forvacuum simultaneously carries out OB operations（Decarburization is forced in oxygen blast）, it is true using full pumping after OB Vacancy is managed, and controls vacuum 150pa；After OB terminates, decarburization circulation time 8min is controlled, decarburization terminates to determine oxygen, remaining oxygen control In 450ppm, and aluminum shot deoxidation is used according to oxygen value is determined, add carbon dust, ferrotianium to carry out alloying component adjustment, RH circulation after deoxidation Time 12min.
（4）RH stoves Oxygen Content in Liquid Steel leaving from station is 12ppm, it is leaving from station before carry out Calcium treatment, molten steel Ca is controlled in 35ppm, soft blow After 8min, conticaster casting is hung to.The mass percent of composition in middle Baogang's water：C：0.015%, Si：0.02%, Mn：0.12%, Ti：0.06%, Al：0.03%, P：0.012%, S：0.010%, balance of Fe and inevitable impurity.
（5）After bloom cogging, 1070 DEG C are warming up to into heating furnace, steel billet of coming out of the stove carries out water under high pressure dephosphorization, into height Fast mill milling.The operation of rolling enters final rolling temperature control at 865 DEG C, and laying temperature is controlled at 900 DEG C.
Into Stelmor cooling line, adjust air-cooled line stay-warm case and open quantity and blower fan aperture, wire rod phase transformation after spinning Leading portion cooldown rate is controlled in 1.5 DEG C/s.
The deep-draw pure iron tensile strength for obtaining is 320Mpa, and cold upsetting 1/3 is qualified.
Embodiment 3
Deep-draw pure iron chemical composition mass percent is as follows：C：0.019%, Si：0.02%, Mn：0.11%, Ti：0.07%, Al：0.05%, P：0.012%, S：0.009%, balance of Fe and inevitable impurity.
Production technology is as follows：
（1）Blast-melted to be blended into converter smelting, tapping adds aluminium block deoxidation, later stage to add lime 3.0kg/T.
（2）After LF enters the station, top slag adds lime 3.0kg/T, and using calcium carbide, aluminum shot slag making；And it is warming up to 1670 DEG C, Top slag color is light green, in slag（FeO+MnO）For 0.88%, molten steel oxygen leaving from station is 25ppm.
（3）Molten steel is hung to into RH stoves, forvacuum simultaneously carries out OB operations（Decarburization is forced in oxygen blast）, it is true using full pumping after OB Vacancy is managed, and controls vacuum 150pa；After OB terminates, decarburization circulation time 8min is controlled, decarburization terminates to determine oxygen, remaining oxygen control In 400ppm, and aluminum shot deoxidation is used according to oxygen value is determined, add carbon dust, ferrotianium to carry out alloying component adjustment, RH circulation after deoxidation Time 15min.
（4）RH stoves Oxygen Content in Liquid Steel leaving from station is 8ppm, it is leaving from station before carry out Calcium treatment, molten steel Ca is controlled in 45ppm, soft blow After 8min, conticaster casting is hung to.The mass percent of composition in middle Baogang's water：C：0.019%, Si：0.02%, Mn：0.11%, Ti：0.07%, Al：0.05%, P：0.012%, S：0.009%, balance of Fe and inevitable impurity.
（5）After bloom cogging, 1080 DEG C are warming up to into heating furnace, steel billet of coming out of the stove carries out water under high pressure dephosphorization, into height Fast mill milling.The operation of rolling enters final rolling temperature control at 880 DEG C, and laying temperature is controlled at 910 DEG C.
Into Stelmor cooling line, adjust air-cooled line stay-warm case and open quantity and blower fan aperture, wire rod phase transformation after spinning Leading portion cooldown rate is controlled in 1.7 DEG C/s.
The deep-draw pure iron tensile strength for obtaining is 332Mpa, and cold upsetting 1/3 is qualified.
Embodiment 4
Deep-draw pure iron chemical composition mass percent is as follows：C：0.021%, Si：0.02%, Mn：0.09%, Ti：0.07%, Al：0.04%, P：0.012%, S：0.008%, balance of Fe and inevitable impurity.
Production technology is as follows：
（1）Blast-melted to be blended into converter smelting, tapping adds aluminium block deoxidation, later stage to add lime 2.5kg/T.
（2）After LF enters the station, top slag adds lime 3.5kg/T, and using calcium carbide, aluminum shot slag making；And it is warming up to 1660 DEG C, Top slag color is with light green, in slag（FeO+MnO）For 0.92%, molten steel oxygen leaving from station is 32ppm.
（3）Molten steel is hung to into RH stoves, forvacuum simultaneously carries out OB operations（Decarburization is forced in oxygen blast）, it is true using full pumping after OB Vacancy is managed, and controls vacuum 150pa；After OB terminates, decarburization circulation time 8min is controlled, decarburization terminates to determine oxygen, remaining oxygen control In 350ppm, and aluminum shot deoxidation is used according to oxygen value is determined, add carbon dust, ferrotianium to carry out alloying component adjustment, RH circulation after deoxidation Time 13min.
（4）RH stoves Oxygen Content in Liquid Steel leaving from station controls 6ppm, it is leaving from station before carry out Calcium treatment, molten steel Ca is controlled in 40ppm, soft blow After 8min, conticaster casting is hung to.The mass percent of composition in middle Baogang's water：C：0.021%, Si：0.02%, Mn：0.09%, Ti：0.07%, Al：0.04%, P：0.012%, S：0.008%, balance of Fe and inevitable impurity.
（5）After bloom cogging, 1085 DEG C are warming up to into heating furnace, steel billet of coming out of the stove carries out water under high pressure dephosphorization, into height Fast mill milling.The operation of rolling enters final rolling temperature control at 885 DEG C, and laying temperature is controlled at 915 DEG C.
Into Stelmor cooling line, adjust air-cooled line stay-warm case and open quantity and blower fan aperture, wire rod phase transformation after spinning Leading portion cooldown rate is controlled in 1.8 DEG C/s.
The deep-draw pure iron tensile strength for obtaining is 348Mpa, and cold upsetting 1/3 is qualified.

Claims (9)

1. a kind of high-intensity fasteners production method of deep-draw pure iron, blast-melted through converter smelting, the refining of LF stoves, RH stoves Refining, continuous casting, controlled rolling and controlled cooling, collection volume operation, obtain the deep-draw pure iron, the deep-draw pure iron chemical composition mass percent For：C：0.015～0.025%, Si≤0.03%, Mn≤0.15%, Ti：0.06～0.08%, Al:0.03-0.05%, P≤ 0.015%, S≤0.015%, balance of Fe and inevitable impurity, it is characterised in that specific embodiment is as follows：
（1）Converter smelting：It is blast-melted to carry out after desulfurization process, combined blown converter smelting is blended into, aluminium block deoxidation, top are added after tapping Slag adds lime 2.0-3.5kg/t；
（2）LF stoves are refined：After LF enters the station, slag charge addition is as follows：Lime 2.0-4.0kg/t, using calcium carbide, aluminum shot slag making, Be warming up to 1650～1680 DEG C, top slag color based on white or light green, FeO and MnO quality sum≤1.0%, molten steel in slag Oxygen≤50ppm leaving from station；
（3）RH stoves are refined：Molten steel is hung to into RH stoves, forvacuum simultaneously carries out oxygen blast pressure Decarburization Operation, in oxygen blast decarburization is forced It is disposed, using aluminum shot deoxidation, adds carbon dust 0.15-0.20kg/t, ferrotianium 1.3-1.6kg/t to carry out alloying component adjustment；
（4）Continuous casting：RH stoves, it is leaving from station before carry out after Calcium treatment and soft blow 8min, being hung to conticaster and being cast into bloom；
The mass percent of composition in middle Baogang's water：C：0.015～0.025%, Si≤0.03%, Mn≤0.15%, Ti：0.06～ 0.08%, Al:0.03-0.05%, P≤0.015%, S≤0.015%, balance of Fe and inevitable impurity；
（5）Controlled rolling and controlled cooling：After bloom cogging, 1070～1090 DEG C are warming up to into heating furnace, steel billet of coming out of the stove carries out water under high pressure Dephosphorization, into fast mill rolling；The operation of rolling enters final rolling temperature for 880 ± 15 DEG C, and laying temperature is 910 ± 10 DEG C, then Jing Collection volume operation, obtains the deep-draw pure iron.
2. production method according to claim 1, it is characterised in that the step（5）In controlled rolling and controlled cooling operation, after rolling Steel billet enter Stelmor cooling line, adjust air-cooled line stay-warm case and open quantity and blower fan aperture, after spinning before wire rod phase transformation Section cooldown rate is 1.5～2.0 DEG C/s.
3. production method according to claim 1, it is characterised in that the step（3）It is described pre- in RH stove refining procedures Vacuumize and carry out oxygen blast to force in decarburization, control parameter is：Remaining oxygen is controlled in 300-450ppm；After aluminum shot deoxidation, control Oxygen Content in Liquid Steel≤15ppm leaving from station.
4. production method according to claim 1, it is characterised in that the step（3）In RH stove refining procedures, oxygen blast is strong After Decarburization Operation processed terminates, using full pumping application of vacuum, vacuum≤150Pa, decarburization circulation time 10-15min is controlled.
5. production method according to claim 1, it is characterised in that the step（3）It is described to add in RH stove refining procedures Entering carbon dust, ferrotianium carries out alloying component adjustment so that C in molten steel：0.015～0.025%, Ti：0.06～0.08%；It is simultaneously leaving from station Calcium treatment, controls Ca：25-45ppm.
6. production method according to claim 1, it is characterised in that the step（3）In RH stove refining procedures, the RH Circulation time 10-15min.
7. production method according to claim 1, it is characterised in that the step（1）In converter smelting operation, blast furnace iron S≤0.013% in water.
8. production method according to claim 1, it is characterised in that the step（4）In continuous casting working procedure, the bloom Specification is 325 × 280mm2。
9. production method according to claim 1, it is characterised in that the step（5）It is described big in controlled rolling and controlled cooling operation Square billet cogging is into 160 × 160mm2Specification.
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