CN107812905A - Large section Properties of Heavy Rail Steel green shell quality optimization control method - Google Patents

Large section Properties of Heavy Rail Steel green shell quality optimization control method Download PDF

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Publication number
CN107812905A
CN107812905A CN201711020747.3A CN201711020747A CN107812905A CN 107812905 A CN107812905 A CN 107812905A CN 201711020747 A CN201711020747 A CN 201711020747A CN 107812905 A CN107812905 A CN 107812905A
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China
Prior art keywords
properties
heavy rail
rail steel
green shell
crystallizer
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CN201711020747.3A
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Chinese (zh)
Inventor
陈亮
陈天明
郭华
李扬洲
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Pangang Group Panzhihua Iron and Steel Research Institute Co Ltd
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Pangang Group Panzhihua Iron and Steel Research Institute Co Ltd
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Priority to CN201711020747.3A priority Critical patent/CN107812905A/en
Publication of CN107812905A publication Critical patent/CN107812905A/en
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    • BPERFORMING OPERATIONS; TRANSPORTING
    • B22CASTING; POWDER METALLURGY
    • B22DCASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D11/00Continuous casting of metals, i.e. casting in indefinite lengths
    • B22D11/10Supplying or treating molten metal
    • B22D11/11Treating the molten metal
    • B22D11/114Treating the molten metal by using agitating or vibrating means
    • B22D11/115Treating the molten metal by using agitating or vibrating means by using magnetic fields
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B22CASTING; POWDER METALLURGY
    • B22DCASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D11/00Continuous casting of metals, i.e. casting in indefinite lengths
    • B22D11/16Controlling or regulating processes or operations
    • B22D11/18Controlling or regulating processes or operations for pouring

Abstract

The invention discloses a kind of large section Properties of Heavy Rail Steel green shell quality optimization control method, particularly a kind of large section Properties of Heavy Rail Steel green shell quality optimization control method for being related to field of steel metallurgy.The large section Properties of Heavy Rail Steel green shell quality optimization control method of the present invention, the electromagnetic mixing apparatus of large section Properties of Heavy Rail Steel crystallizer is installed on its height medium line apart from crystallizer 620mm opening positions in lower section suitable for reading, M-EMS Current strength control scope is 300A to 400A, and stir current frequency is 2.4Hz.Large section (320mm*410mm) the Properties of Heavy Rail Steel casting blank shell quality produced using the large section Properties of Heavy Rail Steel green shell quality optimization control method of the application is good, shell thickness is uniformly distributed vertically, other quality of strand are effectively controlled, especially strand columnar zone develops uniform along width and thickness direction, symmetry is good, the isometric crystalline region symmetry in strand central area is preferable, and low multiple quality norm controlling is more excellent, and corresponding rail superficial dense layer thickness is uniform.

Description

Large section Properties of Heavy Rail Steel green shell quality optimization control method
Technical field
The present invention relates to a kind of large section Properties of Heavy Rail Steel green shell quality optimization control method, particularly one kind is related to steel smelting The large section Properties of Heavy Rail Steel green shell quality optimization control method in golden collar domain.
Background technology
Rail is the main building block of railroad track, in railway transport course, locomotive is provided and effectively supports and draws Lead, be subjected to the huge lateral pressure from wheel.Based on China's infrastructure growth requirement, railway transportation is just with swift and violent speed Degree development, and constantly tend to high speed, heavy loading.Rail specification size also gradually increases, and to reduce welding point, ensures railway The higher globality of rail, the scale of big specification rail are also increasing.By fixed compared with light section strand rolling large-size length in the past The rail of chi undoubtedly requires that strand length scaling is longer, and this causes subsequent heat treatment equipment to need to carry out larger transformation;In addition, such as If casting blank cross-section size is constant, and rail specification becomes large-sized, and this compression ratio to the operation of rolling undoubtedly impacts, final shadow Ring the physical indexs such as rail consistency.In continuous casting production process, strand goes out after crystallizer, all heats of molten steel essentially by Green shell discharges, and the solidification that the quality of green shell dramatically influences molten steel inside strand develops, including solidified structure is integrally uniform Property and circumferential uniformity etc., and for large section Properties of Heavy Rail Steel continuous casting, due to its steel grades and molten steel The influence of solidification and heat transfer principle, casting blank solidification process cross-section temperature gradient is larger, and wick-containing is longer, and solidification of molten steel is held inside strand The continuous time is longer, and the homoepitaxial for strand solidified inside tissue is established important foundation by effective control of green shell quality.
Crystallizer is the part of most critical in continuous casting, and it is referred to as " heart " of conticaster by industry, and it is to green shell The important function of quality control is embodied in:Casting blank shape is qualified when ensureing crystallizer, and has enough thickness resistance molten steel quiet Press and avoid bleedout;Ensure green shell along crystallizer circumference homoepitaxial, above-mentioned effect determines continuous casting rate and strand matter Amount control.There are many scholars to carry out numerous studies to solidification shell quality control, research direction is concentrated mainly on solidification base The prediction of thickness of the shell, the mechanism of the acquisition of green shell safe thickness and casting process bleedout and detection control research, for specific Continuous casting billet shell quality control research it is relatively fewer, particularly with large section (320mm*410mm) continuous casting Properties of Heavy Rail Steel During green shell solidification control research have no substantially.
Such as:
CN104384469A discloses the forecasting system and method for pre-hardening shell thickness in a kind of steel continuous casting crystallizer.This hair It is bright including:Information acquisition module:For gathering casting steel grades, crystallizer physical dimension, submersed nozzle physical dimension, company Casting process condition and along the pre-hardening shell thickness measured value at crystallizer diverse location and interdendritic away from measured value;The crystallization Device physical dimension, including width of plate slab, slab thickness, crystallizer height, copper plate thickness, tank depth, sink thicknesses and nickel dam Thickness;The continuous casting process condition, including the outlet of meniscus position, casting speed, inlet water temperature, wide face exit water temperature, leptoprosopy Water temperature, wide face cooling water flow and leptoprosopy cooling water flow;The submersed nozzle physical dimension, including submersed nozzle immerse Depth and submersed nozzle side opening inclination angle;Steel grade thermal physical property parameter computing module:The casting collected according to information acquisition module Steel grades and interdendritic calculate interdendritic solute segregation and solidification path during solidification of molten steel, and then obtain away from measured value Steel grade thermal physical property parameter simultaneously sends it to crystallizer initial set shell growth prediction module;The steel grade thermal physical property parameter, including it is solid Liquidus temperature, thermal conductivity factor, density, specific heat and latent heat of solidification;Crystallizer initial set shell growth prediction module:By in crystallizer Shape inside macroscopic transport process and crystallizer copper plate surface forming core, molten steel including heat transmission, MOMENTUM TRANSMISSION and mass transport Microcosmic solidified structure including core and grain growth develops behavior and coupled, and the crystallization collected according to information acquisition module Device physical dimension, submersed nozzle physical dimension and continuous casting process condition and from steel grade thermal physical property parameter computing module receive Steel grade thermal physical property parameter, predict the internal high temperature solidification of molten steel process shell growth behavior of casting process crystallizer and send it to knot Fruit output module;As a result output module:Show the crystallizer solidified inside tissue topography of prediction, i.e., pre-hardening green shell life image conversion Growth process, and quantification show crystallizer initial set shell thickness predicted value, by pre-hardening the shell thickness predicted value and information The pre-hardening green shell measured value of crystallizer of acquisition module collection is compared, and the output display comparative result.But for super Some crucial particular contents of big cross section (320mm*410mm) Properties of Heavy Rail Steel green shell quality control equipment technique are not directed to.
CN103386472A discloses a kind of acquisition methods of continuous cast mold outlet green shell safe thickness.The present invention includes Following steps:Measure steel green shell surface temperature Tf, the width B of strand, roller spacing L, ferrostatic pressure P;Calculated by formula The elastic modulus E of flat board;Pass through the bending stiffness D of formula calculate flat board;Calculated by formula between crystallizer outlet and sufficient roller Maximum bulge deformation wmax;Maximum bulge deformation wmax between crystallizer outlet and sufficient roller is less than or equal to the critical bulge of green shell Deformation quantity wc is criterion, determines continuous cast mold outlet green shell safe thickness S scope;Wherein, α is numerical factor, and v is Poisson Than Ts is the solidus temperature of steel.And for large section (320mm*410mm) Properties of Heavy Rail Steel green shell quality control equipment technique Some crucial particular contents be not directed to.
CN101138785 discloses a kind of continuous cast method of bloom, and the technical scheme of the invention is:The continuous casting of bloom Method, including the secondary cooling to green shell, wherein green shell pass sequentially through five spraying and cooling areas and carry out secondary cooling, five sprays It is respectively 151~194l/ (min × m that cooling zone cools down direction intensity of cooling along green shell2), 34~50l/ (min × m2), 23~ 35l/(min×m2), 12~19l/ (min × m2), 8~11l/ (min × m2).The present invention is by during green shell is thickening The intensity of cooling to green shell is gradually reduced, so as to effectively reduce the internal-external temperature difference of green shell, the thermal stress of square billet is reduced, reduces generous Base continuous casting defect.It is the Medium Carbon Steel Containing Manganese such as 450mm × 360mm, material 35Mn2,37Mn2 disclosure is particularly well suited to cross dimension The continuous casting of bloom.But equip the one of technique for the quality control of large section (320mm*410mm) Properties of Heavy Rail Steel green shell A little crucial particular contents are not directed to.
The content of the invention
The invention provides one kind can imitate flow field of molten steel inside optimization crystallizer, weaken casting stream molten steel to solidified shell It is uneven to wash away, make that large section Properties of Heavy Rail Steel casting blank shell thickness is circumferentially uniform, and appearance and size is good, casting blank solidification Tissue distribution Uniform large section Properties of Heavy Rail Steel green shell quality optimization control method.
The present invention is the used large section Properties of Heavy Rail Steel green shell quality optimization control method that solves the above problems, and super large breaks The electromagnetic mixing apparatus of face Properties of Heavy Rail Steel crystallizer is installed on its height medium line apart from crystallizer 620mm opening positions in lower section suitable for reading, M-EMS Current strength control scope is 300A to 400A, and stir current frequency is 2.4Hz.
It is further that cooling water inflow is 3650L/min, hydraulic pressure 0.90MPa in crystallization process.
It is further that cast superheat of liquid steel control is in the range of 15 DEG C~30 DEG C, for the first heat of middle bag, overheat Degree control is at 25 DEG C~40 DEG C;Constant speed cast is carried out with target pull rate 0.68m/min, wherein pulling rate undulated control is in 0.65m/ In the range of min~0.75m/min.
The beneficial effects of the invention are as follows:Produced using the large section Properties of Heavy Rail Steel green shell quality optimization control method of the application Large section (320mm*410mm) Properties of Heavy Rail Steel casting blank shell quality it is good, shell thickness is uniformly distributed vertically, strand other Quality is effectively controlled, and especially strand columnar zone develops uniform along width and thickness direction, and symmetry is good, in strand The isometric crystalline region symmetry in heart district domain is preferable, and low multiple quality norm controlling is more excellent, and corresponding rail superficial dense layer thickness is uniform, other Capability and performance is all qualified.
Embodiment
Large section Properties of Heavy Rail Steel green shell quality optimization control method used by the application, large section Properties of Heavy Rail Steel crystallizer Electromagnetic mixing apparatus be installed on its height medium line apart from crystallizer 620mm opening positions in lower section suitable for reading, M-EMS Current strength control range is 300A to 400A, and stir current frequency is 2.4Hz.Wherein electromagnetic mixing apparatus height medium line is Refer to a virtual elevation line positioned at the half position of electromagnetic mixing apparatus height.The application passes through design construction crystallizer electricity Magnetic stirs reasonable installing position, comprehensive stirring intensity to mould liquid level stability, the optimization of crystallizer flow field, strand segregation with And the influence of equiaxial crystal ratio control determines that reasonable crystallizer electricity stirs current strength, realizes shell thickness in crystallizer, chemical composition Equal control.
Cooling water inflow is 3650L/min, hydraulic pressure 0.90MPa in crystallization process.Quality is cooled down to improve, accurate control Cooling effect, the application are strictly controlled cooling water inflow and hydraulic pressure, to obtain the product of high quality.
To improve box hat product quality, the application is to pouring into a mould superheat of liquid steel, the especially middle degree of superheat for wrapping the first heat Accurately controlled.Superheat of liquid steel control is wherein poured into a mould in the range of 15 DEG C~30 DEG C, for the first heat of middle bag, the degree of superheat Control is at 25 DEG C~40 DEG C;Casting speed control is in the range of 0.65m/min~0.75m/min.
The embodiment of the present invention is further described with reference to embodiment.
Embodiment 1
The embodiment is method production large section (320mm*410) of certain steel mill using the invention of this equipment technology U71Mn heavy rail steel continuous casting billets.Except the use present invention is apart from crystallizer 620mm opening positions installation M-EMS suitable for reading Outside, the stirring intensity of M-EMS is set as 370A, stirring frequency 2.4Hz.Other technological parameters:Crystallizer is cold But water 3650L/min, hydraulic pressure 0.90MPa, actual degree of superheat control range is wrapped in cast as 15 DEG C~27 DEG C, it is average 23 DEG C. The normal casting speed control of casting process keeps 0.68m/min (constant speed cast) ratios up to 86% in 0.65m/min~0.70m/min.
Casting process Mold liquid level stabilizing, covering slag thickness distribution are uniform.It is right after continuous casting terminates U71Mn heavy rails steel continuous casting billet carries out low power detection;Corroded using cold sour dendrite, detection strand cross section shell thickness distribution feelings Condition, as a result show, the Properties of Heavy Rail Steel U71Mn solidification shells thickness that the technological invention is produced is circumferentially distributed uniformly along section, whole Body is controlled in 17~18mm;Strand corner quality is good, and columnar zone develops uniform, isometric crystalline region along width and thickness direction Symmetry is preferable, remaining low multiple quality index:0.5 grade of center porosity, 0 grade of shrinkage cavity, 0.5 grade of center segregation, no other defect.It is right Strand carries out segregation detection, and green shell and its neighbouring carbon degree of segregation replace without obvious negative and positive, and composition is uniform.
Embodiment 2
The embodiment is method production large section (320mm*410) U75V of certain steel mill using the invention of this equipment technology Heavy rail steel continuous casting billet.Except using the present invention in addition to apart from crystallizer 620mm opening positions suitable for reading installation M-EMS, will The stirring intensity of M-EMS is set as 300A, stirring frequency 2.4Hz.Other technological parameters:Crystallizer cooling water 3650L/min, hydraulic pressure 0.90MPa are measured, actual degree of superheat control range is wrapped in cast as 18 DEG C~28 DEG C, it is average 25 DEG C.Cast The normal casting speed control of process keeps 0.68m/min (constant speed cast) ratios up to 81% in 0.67m/min~0.73m/min.
Casting process Mold liquid level stabilizing, covering slag thickness distribution are uniform.After continuous casting terminates, to U75V Heavy rail steel continuous casting billet carries out low power detection;Corroded using cold sour dendrite, detection strand cross section shell thickness distribution situation, as a result It has been shown that, the Properties of Heavy Rail Steel U75V solidification shells thickness that the technological invention is produced is circumferentially distributed uniformly along section, and overall control exists 16~18mm;Strand corner quality is good, columnar zone develop along width and thickness direction it is uniform, isometric crystalline region symmetry compared with It is good, remaining low multiple quality index:0.5 grade of center porosity, 0.5 grade of shrinkage cavity, 0.5~1.0 grade of center segregation, no other defect.It is right Strand carries out segregation detection, and green shell and its neighbouring carbon degree of segregation replace without obvious negative and positive, and composition is uniform.
Embodiment 3
The embodiment is method production large section (320mm*410) of certain steel mill using the invention of this equipment technology U78CrV heavy rail steel continuous casting billets.Stirred except use is of the invention apart from crystallizer 620mm opening positions installation crystallizer electromagnetism suitable for reading Outside mixing, the stirring intensity of M-EMS is set as 400A, stirring frequency 2.4Hz.Other technological parameters:Crystallizer Cooling water inflow 3650L/min, hydraulic pressure 0.90MPa, actual degree of superheat control range is wrapped in cast as 19 DEG C~30 DEG C, average 25 ℃.The normal casting speed control of casting process reaches in 0.66m/min~0.75m/min, 0.68m/min (constant speed cast) ratio of holding 84%.
Casting process Mold liquid level stabilizing, covering slag thickness distribution are uniform.It is right after continuous casting terminates U78CrV heavy rails steel continuous casting billet carries out low power detection;Corroded using cold sour dendrite, detection strand cross section shell thickness distribution feelings Condition, as a result show, the Properties of Heavy Rail Steel U78CrV solidification shells thickness that the technological invention is produced is circumferentially distributed uniformly along section, whole Body is controlled in 15~18mm;Strand corner quality is good, and columnar zone develops uniform, isometric crystalline region along width and thickness direction Symmetry is preferable, remaining low multiple quality index:0.5~1.0 grade of center porosity, 0 grade of shrinkage cavity, 0.5 grade of center segregation, lacked without other Fall into.Segregation detection is carried out to strand, green shell and its neighbouring carbon degree of segregation replace without obvious negative and positive, and composition is uniform.
Above-mentioned embodiment explanation, after the invention of this equipment technology, large section (320mm*410mm) Properties of Heavy Rail Steel Casting blank shell quality is good, and shell thickness is uniformly distributed vertically, and other quality of strand obtain effective optimal control, especially cast Base columnar zone develops uniformly along width and thickness direction, and symmetry is good, and the isometric crystalline region symmetry in strand central area is preferable, Low multiple quality norm controlling is more excellent, and corresponding rail superficial dense layer thickness is uniform, and other capability and performances are all qualified.

Claims (3)

1. large section Properties of Heavy Rail Steel green shell quality optimization control method, it is characterised in that:The electricity of large section Properties of Heavy Rail Steel crystallizer Magnetic agitating device is installed on its height medium line apart from crystallizer 620mm opening positions in lower section suitable for reading, M-EMS Current Strength control scope is 300A to 400A, and stir current frequency is 2.4Hz.
2. large section Properties of Heavy Rail Steel green shell quality optimization control method as claimed in claim 1, it is characterised in that:Crystallizing Cooling water inflow is 3650L/min, hydraulic pressure 0.90MPa in journey.
3. large section Properties of Heavy Rail Steel green shell quality optimization control method as claimed in claim 1, it is characterised in that:Pour into a mould molten steel The degree of superheat is controlled in the range of 15 DEG C~30 DEG C, and for the first heat of middle bag, the degree of superheat is controlled at 25 DEG C~40 DEG C;Drawn with target Fast 0.68m/min carries out constant speed cast, and wherein pulling rate undulated control is in the range of 0.65m/min~0.75m/min.
CN201711020747.3A 2017-10-27 2017-10-27 Large section Properties of Heavy Rail Steel green shell quality optimization control method Pending CN107812905A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110238357A (en) * 2019-07-22 2019-09-17 攀钢集团攀枝花钢铁研究院有限公司 Low rolling reduction Properties of Heavy Rail Steel web of the rail consistency control method

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS61129266A (en) * 1984-11-27 1986-06-17 Sumitomo Metal Ind Ltd Electromagnetic stirring and level measuring device for molten steel
CN105215310A (en) * 2015-11-17 2016-01-06 攀钢集团攀枝花钢铁研究院有限公司 A kind of method that big cross section Properties of Heavy Rail Steel strand center porosity controls
CN105215309A (en) * 2015-11-11 2016-01-06 攀钢集团攀枝花钢铁研究院有限公司 A kind of method that big cross section Properties of Heavy Rail Steel center segregation of casting blank controls
CN105364042A (en) * 2015-11-11 2016-03-02 攀钢集团攀枝花钢铁研究院有限公司 Method for controlling crystalline structure uniformity of large-section heavy rail steel cast blank

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS61129266A (en) * 1984-11-27 1986-06-17 Sumitomo Metal Ind Ltd Electromagnetic stirring and level measuring device for molten steel
CN105215309A (en) * 2015-11-11 2016-01-06 攀钢集团攀枝花钢铁研究院有限公司 A kind of method that big cross section Properties of Heavy Rail Steel center segregation of casting blank controls
CN105364042A (en) * 2015-11-11 2016-03-02 攀钢集团攀枝花钢铁研究院有限公司 Method for controlling crystalline structure uniformity of large-section heavy rail steel cast blank
CN105215310A (en) * 2015-11-17 2016-01-06 攀钢集团攀枝花钢铁研究院有限公司 A kind of method that big cross section Properties of Heavy Rail Steel strand center porosity controls

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110238357A (en) * 2019-07-22 2019-09-17 攀钢集团攀枝花钢铁研究院有限公司 Low rolling reduction Properties of Heavy Rail Steel web of the rail consistency control method

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