CN104334297A - Continuous casting method for slab - Google Patents
Continuous casting method for slab Download PDFInfo
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- CN104334297A CN104334297A CN201280073444.7A CN201280073444A CN104334297A CN 104334297 A CN104334297 A CN 104334297A CN 201280073444 A CN201280073444 A CN 201280073444A CN 104334297 A CN104334297 A CN 104334297A
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- continuous casting
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/04—Continuous casting of metals, i.e. casting in indefinite lengths into open-ended moulds
- B22D11/041—Continuous casting of metals, i.e. casting in indefinite lengths into open-ended moulds for vertical casting
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/16—Controlling or regulating processes or operations
- B22D11/20—Controlling or regulating processes or operations for removing cast stock
- B22D11/207—Controlling or regulating processes or operations for removing cast stock responsive to thickness of solidified shell
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/12—Accessories for subsequent treating or working cast stock in situ
- B22D11/1206—Accessories for subsequent treating or working cast stock in situ for plastic shaping of strands
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B1/00—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations
- B21B1/46—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling metal immediately subsequent to continuous casting
- B21B1/463—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling metal immediately subsequent to continuous casting in a continuous process, i.e. the cast not being cut before rolling
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/06—Continuous casting of metals, i.e. casting in indefinite lengths into moulds with travelling walls, e.g. with rolls, plates, belts, caterpillars
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/10—Supplying or treating molten metal
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/12—Accessories for subsequent treating or working cast stock in situ
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/12—Accessories for subsequent treating or working cast stock in situ
- B22D11/128—Accessories for subsequent treating or working cast stock in situ for removing
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/12—Accessories for subsequent treating or working cast stock in situ
- B22D11/128—Accessories for subsequent treating or working cast stock in situ for removing
- B22D11/1281—Vertical removing
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/14—Plants for continuous casting
- B22D11/141—Plants for continuous casting for vertical casting
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/16—Controlling or regulating processes or operations
- B22D11/20—Controlling or regulating processes or operations for removing cast stock
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/16—Controlling or regulating processes or operations
- B22D11/22—Controlling or regulating processes or operations for cooling cast stock or mould
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Continuous Casting (AREA)
- Metal Rolling (AREA)
Abstract
Provided is a method for continuously casting slabs which is characterized by employing a moveable roll reduction device provided with rollers capable of reducing slab thickness and capable of moving in a vertical direction along the slab from a mold, and, after drawing of a slab is completed, carrying out reduction as the rollers move in the vertical direction along the halted slab. The movement direction of the rollers when reducing the slab may also be a vertical upward direction. Furthermore, a cross-section of the slab may also be round. According to this continuous casting method, porosity and voids in the center of the slab and shrinkage cavities and voids in the top part of the slab can be reduced at a low equipment cost and without a drop in surface quality, regardless of the size of the cross-sectional area.
Description
Technical field
The present invention relates to a kind of by using pair of rolls to depress strand (slab) thus reducing the continuous casing of the strand of the generation as loose (Japanese: ザ Network) of internal flaw, pore and shrinkage cavity, particularly relating to a kind of use can the continuous casing of roller of movement.
Background technology
Now, in the manufacture of steel, cast strand by continuous casting process, in order to final products, and usually the processing such as breaking down, rolling is implemented to its strand.But, present situation is, as final products, the large-scale blank that such as cross section is larger as the blank of boiler water tank, large mold needs small lot and heavy in section strand, therefore the strand for large-scale blank is not continuous casting, but molten steel is flowed into casting mold and make it solidify and be cast into large-scale steel ingot, this is present situation.Below, the method is called " steel ingot method ".
Although be small lot, be starkly lower than the efficiency of continuous casting process by the efficiency of steel ingot method casting large-scale steel ingot, in addition, if consider, the necessity of steel ingot top rising head or molten steel residue in running channel, cast tubes etc., and yield rate is very low.In addition, rising head mentioned here refers to, when teeming, and the shrinkage cavity that the solidification shrinkage for preventing because of molten steel produces, contraction crack and supplement the molten steel of solidification shrinkage amount.
And, when having cast heavy in section strand when utilizing continuous casting process, the central part of strand produce loose, easily become large as the pore of air blister defect and segregation.Mentioned here loosening refers to, when casting alloy slab (Japanese: alloy ス ラ Block), results from the cavity blemish of the central part of slab.In addition, at the end of casting, after stopping supplying molten steel in casting mold, due to solidification shrinkage, that larger shrinkage cavity can be seen until its casting direction downstream part produces at the meniscus (liquid level) from strand in common steel ingot method.These internal flaws etc. not only make the yield penalty of product, and residue in final products sometimes, become the main cause of product defects.
As the manufacture method of the good heavy in section strand of inside quality, in patent document 1, following a kind of scheme is proposed: for the manufacture of the thick flat ingot casting of spy etc., the casting mold that adopts inverted cone shape in the semi-continuous casting that is difficult to the large-scale steel ingot cast continuous casting machine in the past in thickness.In addition, recording in this patent document 1 can by improving the quality of steel ingot further with the meniscus of electric approach heating steel ingot top (top).
In patent document 2, recording following content: in the continuous casting of strand, by the shape of strand being set to the taper that two sides expand upward gradually, the generation of the internal flaws such as loose, pore can be reduced.
On the other hand, being usually known to following method: in order to reduce the internal flaw such as pore, segregation in the continuous casting of strand, solidifying the surface of depressing strand latter stage.Such as, in patent document 3, record the method for not solidifying pressure strand.
As technology described in patent document 1 and 2, by adopting the casting mold of taper, the shape of strand being set to taper, the effect of rising head in the past can be made up to a certain extent.But in these methods, casting method is complicated and equipment cost is higher, but suppress limited efficiency that is loose and pore, and become large and its inhibition diminishes along with the cross section of strand.In addition, for the method for the meniscus on heating strand top, when strand length is longer, then can not get the effect that inside quality brings up to the central portion of strand, and expensive in equipment, and energy aspect is also uneconomical, therefore can not be called very effective method.
To this, as the continuous casting of common continuous casting machine, by strand roller etc. under surface pressure, thus the method (depressing method online) that the pore of inside is eliminated by the generation stage of pore in inside is absolute very effective method.But, when this online pressure method is used for the continuous casting of heavy in section strand, there is following two problems,
1st problem is, online pressure method is not can extrude in which of casting the pore resulting from strand in stage, but has most suitable pressure period.Such as, if at the generation phase pressure strand of pore, Ze center solid rate is better to the period of solidifying latter stage solidifying completely from about 0.5, if after solidifying completely, then the central part of strand temperature also sufficiently high just solidified after period better.Therefore, in common continuous casting, usually such near the outlet of continuous casting machine specific position arranges the screwdown gears such as depress roller.
But, when casting heavy in section strand, utilize the screwdown gear near the outlet being arranged at continuous casting machine, when depressing strand under the condition being best suited for the loose and pore of extruding, in order to ensure the time solidifying completely to strand, need the length of continuous casting machine to be formed longer.At this, the meniscus in casting mold can be thought to the length of finally solidifying position of strand and to be directly proportional to 2 powers of the thickness of strand.Therefore, if such as using the situation of the strand of thickness 300mm as benchmark, then the continuous casting machine by 9 times of length is needed for the strand of thickness 900mm, needs huge construction cost.
On the other hand, when not formed longer by the length of continuous casting machine, in order to ensure the time solidifying completely to strand, expect the method reducing casting speed.It has been generally acknowledged that 2 powers of the thickness of casting speed (speed of strand) and the strand finally solidifying position are inversely proportional to.Therefore, if using the casting speed of the strand of thickness 300mm be such as the situation of 1m/min as benchmark, then must carry out the casting of the 0.11m/min of pole low speed to the strand of thickness 900mm.The heat supply that such pole low speed casting produces on the meniscus in casting mold is not enough, thus produce because the skinning of meniscus solidifies, produces at meniscus the undulatory casting surface etc. that the contraction due to solidified shell causes, cause the surface quality of strand significantly to reduce.In order to prevent this surface quality from reducing, can expect utilizing plasma heating simultaneously, Joule heat heats meniscus, but equipment cost is higher as described above, and uneconomical in the energy.
2nd problem is that, when the cross section of strand is larger, the infiltration of depressing to strand inside is insufficient, and worry cannot fully extrude loose, pore.
Prior art document
Patent document
Patent document 1: Japanese Laid-Open Patent Publication 62-161445 publication
Patent document 2: Japanese Unexamined Patent Publication 2004-243352 publication
Patent document 3: Japanese Unexamined Patent Publication 2000-288705 publication
Summary of the invention
the problem that invention will solve
As mentioned above, in continuous casting in the past, reduce in loose, the pore of the central part of the larger strand in cross section and the shrinkage cavity on strand top, loose method, in equipment cost, the energy, surface quality in have problem.
The present invention makes in view of such the problems of the prior art, its problem is to provide a kind of following method: in continuous casting, with lower equipment cost and when surface quality can not be caused to reduce, regardless of the size of the sectional area of strand, all reduce the shrinkage cavity on the loose of the central part of strand and pore and strand top, loosen.
for the scheme of dealing with problems
The present inventors, in order to solve above-mentioned problem, is studied the reduction method of the strand in continuous casting.Its result, has following opinion: in order to depress strand, can the roller of movement by adopting, regardless of the size in the cross section of strand, can both being best suited for that extruding is loose, the position of pore and shrinkage cavity depresses.In this case, do not need as adopt be fixed on the roller of ad-hoc location situation adjust length, the casting speed of continuous casting machine, and equipment cost is very low.
The present invention makes based on above-mentioned opinion, and its purport is the continuous casing of the strand shown in following (1) ~ (4).
(1) a kind of continuous casing of strand, in the method, continuous casting strand, it is characterized in that, in drawing strand, under the state making this strand stop movement, use pair of rolls to guide supporting strand, after the drawing completing strand, make the strand of stopping while mobile while use described pair of rolls to depress this strand in vertical, described pair of rolls can switch the guiding supporting of strand and to depress and can pair of rolls in the below of casting mold along strand movement in vertical.
(2) continuous casing of the strand according to above-mentioned (1), is characterized in that, the moving direction of the above-mentioned roller of pressure strand is vertical direction upwards.
(3) continuous casing of the strand according to above-mentioned (1) or (2), is characterized in that, the cross section of strand is circular.
the effect of invention
According to the continuous casing of strand of the present invention, utilize the continuous casting machine that equipment cost is lower, when surface quality can not be caused to reduce, the no matter size in the cross section of strand, significantly can both reduce loose, pore and shrinkage cavity, and can with higher yield rate casting strand.
Accompanying drawing explanation
Fig. 1 is the structure chart of the continuous casting machine that can be suitable for method of the present invention, and (a) of Fig. 1 is front view, and (b) of Fig. 1 is side view.
Fig. 2 is the figure that the casting process undertaken by continuous casing of the present invention is described, (a) of Fig. 2 represents the state of casting start time, (b) of Fig. 2 represents the state in strand drawing, (c) of Fig. 2 represents makes mobile rollers move to the state of the lower end of movable range after drawing terminates, (d) of Fig. 2 represents state depress strand and make mobile rollers increase on one side, and the state of end is depressed in (e) expression of Fig. 2.
Fig. 3 is the figure representing the drafts of strand relative to the relation between the ratio not solidifying footpath (drafts/do not solidify footpath) and defect area rate, (a) of Fig. 3 represents that the actual conditions in normal portion, (b) of Fig. 3 represent the actual conditions on strand top.
Detailed description of the invention
Fig. 1 is the structure chart of the continuous casting machine that can be suitable for method of the present invention, and (a) of Fig. 1 is front view, and (b) of Fig. 1 is side view.Continuous casting machine shown in Fig. 1 is vertical type, and the casting direction of strand is that vertical is downward.This continuous casting machine possesses: casting ladle 1, for holding molten steel; Casting mold 2, from casting ladle 1 via not shown immersion nozzle supply molten steel; And mobile rollers screwdown gear 4, for depressing the strand 3 from casting mold 2 drawing downwards.Casting mold 2 makes half casting mold combination and is formed.Mobile rollers screwdown gear 4 possesses framework 6 for backing roll 5 and pair of rolls 5, and this framework 6 is integrated with 5 one-tenth, roller and can moves up and down along vertical along strand 2 in the below of casting mold 2.
As shown in Fig. 2 described later, immediately below casting mold 2, be neighboringly configured with backing roll group 7 (not shown in Fig. 1) with casting mold 2, and form the support region of the solidified shell 3a of strand 3.Preferably, in continuous casting machine, the place contiguous with casting mold 22 immediately below at least casting mold 2 is with the area supporting solidified shell 3a of the equal extent of the length of the 1/4 ~ casting mold 2 of the length of casting mold 2.In Fig. 2 described later, represent the situation that the length of the length of support region and casting mold 2 is equal.
Roller 5 is configured to switch between this two effect in the mode of the effect of the depress roller of the effect and pressure strand 3 that have the pinch roll guiding supporting strand 3 concurrently, and is pressed by strand direction from the back side under the effect of hydraulic pressure in the mode being contacted with strand 3.In addition, roller 5 is connected to large-scale reductor 9 by Hooks coupling universal coupling 8, and as driven roller work.
Framework 6 by 4 by vertical the adjustment axle (Japanese: ジ ャ ッ キ Shaft) 10 that forms of the ball-screw that configures be supported to and can move in vertical, also applied the driving force that can move up and down along vertical by the guiding mechanism of adjustment axle 10.
Roller 5 is owing to being integrated with framework 6, therefore, it is possible to move up and down along strand 2 along vertical, and the depressing position and depressing that can change strand 3 moves.The movement of roller 5 can be undertaken by making roller 5 self rotate under the state clipping strand 3, and can change moving direction by the direction of rotation changing roller 5.In addition, roller 5, with under the discontiguous state of strand 3, can utilize the guiding mechanism of adjustment axle 10 to move.
Fig. 2 is the figure that the casting process undertaken by continuous casing of the present invention is described, (a) of Fig. 2 represents the state of casting start time, (b) of Fig. 2 represents the state in strand drawing, (c) of Fig. 2 represents to make mobile rollers move to the state of the lower end of movable range after drawing terminates, (d) of Fig. 2 represents state depress strand and make mobile rollers increase on one side, and the state of end is depressed in (e) expression of Fig. 2.
Use Fig. 2 that continuous casing of the present invention is described.First, as shown in (a) of Fig. 2, start the casting of strand 3, and as shown in (b) of Fig. 2, continuous drawing strand 3.Now, roller 5 is configured in the position contiguous with casting mold 2 immediately below casting mold 2, and with the backing roll group 7 contiguous position of actual disposition immediately below backing roll group 7, uses as pinch roll.When strand 3 is drawn to the limit of continuous casting machine, then strand 3 is made to stop thus terminating drawing.Then, as shown in (c) of Fig. 2, make roller 5 move to movable range bottom.Then, the temperature of central part of the standby until strand 3 of roller 5 and the thickness of solidified shell 3a become the condition being best suited for pressure.
After the state of strand 3 becomes the condition being best suited for pressure, roller 5 is pressed on strand 3 until the drafts of strand 3 reaches the amount of regulation, and roller 5 is rotated to the direction contrary with during drawing, as shown in (d) of Fig. 2, the axis along strand 3 makes roller 5 rise and depresses strand 3.When the inside of solidified shell 3a have do not solidify molten steel 3b, as shown in (e) of Fig. 2, making roller 5 increase by depressing strand 3, not solidifying molten steel 3b and being forced on the meniscus on top.The size in the portion of not solidifying when although the molten steel amount of this extrusion also depends on that strand is depressed, when the cross section of strand is circular, compared with the situation of other shapes, be not so much, for the degree in casting mold 2 can be contained in.On the other hand, after strand 3 is solidified to inside completely, when depress make roller 5 increase, naturally do not have the extrusion of not solidifying molten steel.
Like this, by using mobile rollers screwdown gear 4 to depress strand 3, regardless of the size in the cross section of strand 3, can both to depress strand 3 efficiently overall on ground, and make to loosen, pore extruding.The pressure of strand 3 both can be carried out continuously, also can only carry out intermittently by pressure necessary part.
The pressure condition of strand 3 can be changed by the rate of climb changing roller 5.Such as, by the drawing speed of the rate of climb of roller 5 and strand 3 is set to identical speed, can depress at identical conditions strand 3 entirety.This is because, even if rise in the time course after starting in the pressure of roller 5, the molten steel that do not solidify of strand 3 inside also solidifies, portion of not solidifying reduces gradually, by the rate of climb of roller 5 being set to the speed identical with the drawing speed of strand 3 thus becoming constant for the time of depressing position from casting to depressing, the size in the portion of not solidifying of depressing position keeps constant.But the rate of climb of roller 5 also can be set to the speed different from the drawing speed of strand 3.
Only using the shrinkage cavity under meniscus and loose generation as the object suppressed when, make roller 5 not depress the position of the regulation just rising to casting mold 2 adjacent bottom portions to strand 3, make roller 5 increase from this position and depress strand 3 until the assigned position on top.On the contrary, also can be make roller 5 not depress the assigned position just rising to portion more top than the position of the regulation of casting mold 2 adjacent bottom portions to strand 3, roller 5 be declined from this position depress strand 3 until the position of regulation of casting mold 2 adjacent bottom portions.
By above operation, owing to completing the operation pulling to pressure rising from strand of 1 time, therefore, after taking out of strand, the casting of next time repeats the operation shown in Fig. 2 again.
Like this, can the roller of movement by adopting, utilize identical continuous casting machine, when with lower equipment cost and when surface quality can not be caused to reduce, no matter how the size of the sectional area of strand can both cast the strand with good inside quality.In addition, owing to being continuous casting, can with the yield rate casting strand higher than steel ingot method.
In the above description, as continuous casing, although the description of the situation of the continuous casting machine of use vertical type, but continuous casting machine of the present invention can be suitable for and be not limited to vertical type, as long as the part of casting is carried out in the position contiguous with casting mold had immediately below casting mold towards the direction that vertical is downward, even if vertical flexure type (Japanese: vertical ベ Application デ ィ Application グ type), arc bend be curved etc., form also can be suitable for the present invention.
Preferably, the cross section of the strand cast is for circular.Cross section is that the strand of circle is when depressing by level and smooth pair of rolls, then for loose, the pore that the central part at strand produces, the solidified shell except the surrounding of roller contact site is not made to produce larger distortion, only produce between pair of rolls contact site and be out of shape, just under the effect of less pressure counter-force, loose, pore can be extruded efficiently.
In addition, when configuring mobile rollers screwdown gear, the backing roll group being located at the strand of continuous casting machine in the past, keep the roller baffle plate (Japanese: ロ ー ラ エ プ ロ Application) of this backing roll group due to this mobile rollers screwdown gear geometrical interference, therefore arrange be extremely difficult.If do not arrange backing roll group, then worry be subject to the static pressure not solidifying molten steel of strand inside due to solidified shell and cause the generation of casting blank bulging (Japanese: cast sheet バ Le ジ Application グ).But, by the cross section of strand is set to circle, even if be subject to molten steel static pressure with the state solidified shell not arranging backing roll group to a certain degree, also can be difficult to bulge is produced.
Carry out under the state that the pressure of strand both can have at strand internal residual the portion of not solidifying, carry out under the state also can solidified completely at strand.Due to the difference of the steel grade of cast object, if sometimes depress under the state remaining the portion of not solidifying, in strand, produce underbead crack, in this case, depress after strand solidifies completely.In addition, the loose and pore produced due to the difference of steel grade is little, therefore in this case, can be carried out loose and pore extruding by the pressure after solidifying completely fully.
Embodiment
In order to confirm the effect of the continuous casing of strand of the present invention, because this has been following foundry trial (pilot study and formal test).
1. pilot study
1-1. experimental condition
The strand cast is the small-sized strand of diameter 300mm, length 1800mm, and steel grade is the 13%Cr steel that loose gentle pore volume easily increases.As continuous casting machine, use the continuous casting machine shown in above-mentioned Fig. 1.But, be not provided with the backing roll group of the solidified shell for supporting strand.The diameter of the roller that mobile rollers screwdown gear is provided with is 450mm, depressing force is 100t to the maximum, maximum depression torque is 50tm.The pressure rate of climb of mobile rollers screwdown gear is set to 0.8m/min, after the casting of strand total length terminates, depresses whole strand total length.The drafts of strand counts 20mm ~ 70mm with the reduction of the diameter depressing the strand in direction.But, make the cross sectional shape of strand become flat by pressure.
In addition, depressing position do not solidify part diameter (hereinafter referred to as " not solidifying footpath ".) be 70mm or 110mm.This be using be equivalent to solid rate 0.8 thermoisopleth as solid liquid interface to define time value.Solid rate is that the position at the interface of 0.8 is solidified parsing (Japanese: unsteady flo w Den Hot solidifies parsing) by the One dimensional unsteady heat conduction of cylinder section and obtained.The temperature survey of the strand inside that the temperature survey of comparison between calculation results and casting billet surface, thermocouple are carried out, by adding each result of the measurement of not solidifying footpath that the tracers such as S carry out, thus to confirm to resolve precision be enough.
1-2. result of the test
After off-test, to make the mode exposed through the longitudinal section at the center of strand cut off each strand, and section is cut, after grinding, the generation situation of loose, pore and shrinkage cavity is investigated.These each defects present space on the cross section of strand, and the ratio (voidage) that the area in this degree space, space accounts for the area of cross section entirety calculates.With being different from strand that the strand depressed is cast in addition, that do not utilize roller to carry out depressing (hereinafter referred to as " non-pressure strand ".) voidage divided by this voidage, the value this removed is defined as defect area rate, and the index of generation situation as defect.The area in space is used general image photograph to resolve software and measures, also can be measured by other method.
Fig. 3 represents the figure of drafts relative to the relation between the ratio (drafts/do not solidify footpath) not solidifying footpath of strand and defect area rate, (a) of Fig. 3 represents the actual conditions in normal portion, and (b) of Fig. 3 represents the actual conditions on strand top.Strand top refers to and produce region that is loose and shrinkage cavity on non-pressure strand, strand depress is equivalent on non-pressure strand, produce region that the is loose and region of shrinkage cavity.Normal portion refers to the region except strand top of strand.
As shown in (a) of Fig. 3, distinguish: if drafts/do not solidify the value change in footpath greatly, then significantly can reduce loose and pore.In addition, can confirm from (b) of Fig. 3: on strand top compared with normal portion, there is the effect significantly reducing defect further.
2. formal test
The research of 2-1. casting condition
Based on the result of pilot study, about the situation increasing molten steel scale as formal test, carry out the research of casting condition.The strand cast is diameter 800mm, length 10m, and steel grade is 13%Cr steel.The molten steel amount being used for casting this strand is set to about 40t.This is equivalent to utilize common steel ingot method to cast the amount of 4 steel ingots (molten steel amount 10t).Usually, in the casting of steel ingot, in order to prevent the shrinkage cavity on strand top and loosen and use rising head.Molten steel amount needed for rising head is the quality 10% of the molten steel amount of casting needed for every 1 steel ingot, therefore the molten steel needing 4t more.After the casting of steel ingot, emit notch portion because needs cut away, produce the loss of cutting away partial response with it, but do not produce this loss in continuous casting process.
As continuous casting machine, use the continuous casting machine shown in above-mentioned Fig. 1.Casting mold is the water-cooled casting mold made of copper of diameter 800mm, length 800mm.The position contiguous with casting mold immediately below casting mold is provided with backing roll group, and the length of support region is set to 800mm.The diameter of set roller is set to 650mm by mobile rollers screwdown gear.The cooling of strand is set to the water-spraying control of specific water 0.2L/kg-steel.Casting speed is set to 0.25m/min and carrys out drawing strand, stopped drawing when the length of strand reaches 10m.Condition beyond it is identical with above-mentioned pilot study.
Heat conduction of solidifying according to carrying out the continuous casting under above condition is resolved, and the position being speculated as the meniscus 4m of surface temperature in the casting direction in casting mold of strand when drawing stops is about 1220 DEG C, and the position of 10m is about 980 DEG C.Do not solidify footpath for this moment, using solid rate 0.8 as benchmark, the position be speculated as apart from meniscus 4m is about 620mm, and the position of 10m is 500mm.Based on this analysis result, the drafts of the strand utilizing mobile rollers screwdown gear to carry out is set to 225mm, the rate of climb of mobile rollers screwdown gear is set to 0.25m/min.This rate of climb, due to identical with the drawing speed of strand, therefore depresses condition (surface temperature of not solidifying footpath and strand of the strand of depression) all identical in the whole regional extent of strand.
In this case, the footpath of not solidifying of depression when pressure starts is about 500mm, and surface temperature is 980 DEG C.Relative to not solidifying footpath 500mm, drafts is 225mm, and the value in drafts/do not solidify footpath is 0.45, and being therefore speculated as defect area rate in normal portion as pilot study result from above-mentioned Fig. 3 is 20%, is 4.8%, reduces all significantly on strand top.The diameter being located at the roller of mobile rollers screwdown gear is 650mm, and the deformation drag as the 13%Cr steel of cast object is 6kgf/mm
2, therefore when the contact angle of roller and strand is set to 32 °, required depressing force is 650t.
2-2. result of the test
At the fluid origin strand of above condition compared with not being provided with the situation of mobile rollers screwdown gear, the generation of loose, pore and shrinkage cavity is less, inside quality and surface quality good.In addition, compared with the steel ingot by the fluid origin equal size of steel ingot method, higher yield rate can be obtained.
utilizability in industry
According to the continuous casing of strand of the present invention, utilize the continuous casting machine that equipment cost is lower, when surface quality can not be caused to reduce, the no matter size in the cross section of strand, significantly can both reduce larger loose, the pore of width and shrinkage cavity, and can with higher yield rate casting strand.
description of reference numerals
1, casting ladle; 2, casting mold; 3, strand; 3a, solidified shell; 3b, do not solidify molten steel; 4, mobile rollers screwdown gear; 5, pair of rolls; 6, framework; 7, backing roll group; 8, Hooks coupling universal coupling, 9, large-scale reductor; 10, axle is adjusted.
Claims (3)
1. a continuous casing for strand, in the method, continuous casting strand, is characterized in that,
In drawing strand, under the state making this strand stop movement, pair of rolls is used to guide supporting strand,
After the drawing completing strand, make the strand of stopping mobile while use described pair of rolls to depress this strand in vertical,
Described pair of rolls can to switch the guiding of strand supporting and pressure and can pair of rolls in the below of casting mold along strand movement in vertical.
2. the continuous casing of strand according to claim 1, is characterized in that,
The moving direction of the above-mentioned roller of pressure strand is vertical direction upwards.
3. the continuous casing of strand according to claim 1 and 2, is characterized in that,
The cross section of strand is circular.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| PCT/JP2012/003388 WO2013175536A1 (en) | 2012-05-24 | 2012-05-24 | Continuous casting method for slab |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN104334297A true CN104334297A (en) | 2015-02-04 |
Family
ID=49623271
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201280073444.7A Pending CN104334297A (en) | 2012-05-24 | 2012-05-24 | Continuous casting method for slab |
Country Status (8)
| Country | Link |
|---|---|
| EP (1) | EP2857122B1 (en) |
| JP (1) | JPWO2013175536A1 (en) |
| KR (1) | KR20140147883A (en) |
| CN (1) | CN104334297A (en) |
| ES (1) | ES2651136T3 (en) |
| IN (1) | IN2014DN08553A (en) |
| PL (1) | PL2857122T3 (en) |
| WO (1) | WO2013175536A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107116192A (en) * | 2017-06-27 | 2017-09-01 | 中冶京诚工程技术有限公司 | Continuous casting billet screwdown device |
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| JPS6333163A (en) * | 1986-07-26 | 1988-02-12 | Kawasaki Steel Corp | Production for large size ingot |
| JPH03155441A (en) * | 1989-08-16 | 1991-07-03 | Daido Steel Co Ltd | Vertical continuous casting method and apparatus thereof |
| JPH06190521A (en) * | 1992-12-26 | 1994-07-12 | Sumitomo Metal Ind Ltd | Production of large cast bloom |
| JPH08206803A (en) * | 1995-01-30 | 1996-08-13 | Daido Steel Co Ltd | Method for continuously casting different kinds of steels |
| JP2000326060A (en) * | 1999-05-07 | 2000-11-28 | Sms Schloeman Siemag Ag | Method and apparatus for producing continuously cast steel material |
| CN2579561Y (en) * | 2002-11-27 | 2003-10-15 | 钢铁研究总院 | Continuous blank withdrawal straightening device with light pressing function |
| JP2011140044A (en) * | 2010-01-08 | 2011-07-21 | Sumitomo Metal Ind Ltd | Continuous casting method for steel |
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| JPS62161445A (en) | 1986-01-10 | 1987-07-17 | Kawasaki Steel Corp | Steel ingot making method |
| JP3402251B2 (en) | 1999-04-06 | 2003-05-06 | 住友金属工業株式会社 | Continuous casting method |
| JP2004243352A (en) | 2003-02-12 | 2004-09-02 | Daido Steel Co Ltd | Continuous casting method |
| JP5477269B2 (en) * | 2010-12-03 | 2014-04-23 | 新日鐵住金株式会社 | Continuous casting method for slabs |
| JP5741402B2 (en) * | 2011-11-25 | 2015-07-01 | 新日鐵住金株式会社 | Continuous casting method for circular section slabs |
-
2012
- 2012-05-24 ES ES12877100.3T patent/ES2651136T3/en active Active
- 2012-05-24 KR KR1020147031133A patent/KR20140147883A/en not_active Application Discontinuation
- 2012-05-24 IN IN8553DEN2014 patent/IN2014DN08553A/en unknown
- 2012-05-24 CN CN201280073444.7A patent/CN104334297A/en active Pending
- 2012-05-24 PL PL12877100T patent/PL2857122T3/en unknown
- 2012-05-24 WO PCT/JP2012/003388 patent/WO2013175536A1/en active Application Filing
- 2012-05-24 JP JP2014516513A patent/JPWO2013175536A1/en active Pending
- 2012-05-24 EP EP12877100.3A patent/EP2857122B1/en not_active Not-in-force
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6333163A (en) * | 1986-07-26 | 1988-02-12 | Kawasaki Steel Corp | Production for large size ingot |
| JPH03155441A (en) * | 1989-08-16 | 1991-07-03 | Daido Steel Co Ltd | Vertical continuous casting method and apparatus thereof |
| JPH06190521A (en) * | 1992-12-26 | 1994-07-12 | Sumitomo Metal Ind Ltd | Production of large cast bloom |
| JPH08206803A (en) * | 1995-01-30 | 1996-08-13 | Daido Steel Co Ltd | Method for continuously casting different kinds of steels |
| JP2000326060A (en) * | 1999-05-07 | 2000-11-28 | Sms Schloeman Siemag Ag | Method and apparatus for producing continuously cast steel material |
| CN2579561Y (en) * | 2002-11-27 | 2003-10-15 | 钢铁研究总院 | Continuous blank withdrawal straightening device with light pressing function |
| JP2011140044A (en) * | 2010-01-08 | 2011-07-21 | Sumitomo Metal Ind Ltd | Continuous casting method for steel |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107116192A (en) * | 2017-06-27 | 2017-09-01 | 中冶京诚工程技术有限公司 | Continuous casting billet screwdown device |
Also Published As
| Publication number | Publication date |
|---|---|
| JPWO2013175536A1 (en) | 2016-01-12 |
| EP2857122B1 (en) | 2017-09-20 |
| KR20140147883A (en) | 2014-12-30 |
| PL2857122T3 (en) | 2018-02-28 |
| WO2013175536A1 (en) | 2013-11-28 |
| IN2014DN08553A (en) | 2015-05-15 |
| EP2857122A1 (en) | 2015-04-08 |
| EP2857122A4 (en) | 2016-01-20 |
| ES2651136T3 (en) | 2018-01-24 |
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