A kind of continuous casting billet withdrawing technology and special-purpose crystallizer structure thereof
Technical field
The architecture advances that the present invention relates to a kind of continuous casting of iron and steel production technology and use the special crystallizer of this technology.
Background technology
Continuous casting is the main mode of production that modern steel is produced, and conticaster is a special equipment of realizing this mode of production, and crystallizer is the core component of conticaster, the output of the performance decision casting machine of crystallizer, the quality and the cast steel grade of steel billet.
Molten steel solidifying in conticaster crystallizer is a heat that discharges and transmittance process, forms the base shell simultaneously.The base shell solidifies on the heat release limit while moving.Form the quite long strand of liquid core.Conticaster can be divided into three heat transfer cold-zones:
The primary cooling zone molten steel forms enough base shells in crystallizer, to guarantee not bleedout;
The secondary cooling zone water spray solidifies strand to quicken the transmission of strand internal heat fully;
Three cooling zone strands radiant heat transfer in air;
The process of setting of molten steel in crystallizer is very complicated, because the strong cooling effect of copper wall, molten steel just begins to be frozen into shell under the meniscus level, scull is along with throwing motion decline progressive additive, the scull cooling is shunk with the copper wall and is broken away from and the generation air gap, thereby weaken the cooling effect of crystallizer, continue it, scull has part to contact again with the copper wall under the ferrostatic pressure effect.In vertically air gap formation, disappearance, form again, be interruption and occur, so also variation thereupon of the hot-fluid on the copper wall.Hot transfer route is in the crystallizer: molten steel---solidified shell---air gap---cooling agent (cooling water).Wherein the maximum guarantee of Chuan Reing is an air gap.For reducing the air gap influence, improve the heat-conducting effect of crystallizer, the base shell is solidified be tending towards evenly, crystallizer will have suitable back draught.General back draught is 0.5~1.0%, and the crystallizer that back draught is big is derived more heat, but the resistance of throwing is along with increase; Excessive back draught can make base shell drawing crack (transverse crack occurring), and strand can be stuck in the crystallizer when serious.
The crystallizer that existing conticaster is adopted, its structure have monoblock type and make up two kinds, and in stable casting process, no matter adopt the crystallizer of the sort of form, its geometry is constant; Plate slab crystallizer just can be adjusted copper coin position, narrow limit when changing width of plate slab, after adjusting width and back draught, in steel pouring process, the relative position of copper plate of crystallizer is constant; Crystallizer vibrates on the direction of motion that is parallel to molten steel (steel billet), is being changeless perpendicular to the molten steel direction of motion, and for preventing the steel billet bleedout, the back draught of crystallizer can not be transferred too greatly; The back draught of crystallizer and the capacity of heat transmission exist and directly to get in touch, within the specific limits, the back draught of crystallizer is big more, the capacity of heat transmission of crystallizer is just big more, for preventing bleedout, the back draught of crystallizer can not be transferred maximumly or do maximumly, causes the potential capacity of heat transmission of crystallizer not bring into play.Like this, because in process of billet withdrawal, the geometry of crystallizer is fixed, and its back draught remains unchanged, and has contradiction with problems such as preventing bleedout with regard to making improving pulling rate, and for preventing problem such as bleedout, casting speed is restricted.
Summary of the invention
The present invention is directed to the existing existing problem of continuous casting billet withdrawing technology, propose a kind ofly can improve casting speed and prevent bleedout, avoid producing the continuous casting throwing new technology of problems such as bridging, segregation, and further propose a kind of new construction that can adapt to the special crystallizer of this billet withdrawing technology.
Technical scheme of the present invention also is that the principle of solidifying when molten steel is carried out billet withdrawing technology in crystallizer is done to propose on the basis of deep study and analysis, and the inventor thinks: improve casting speed and must the further ways such as air gap that reduce between base shell and the crystallizer copper wall reduce thermal resistance.Reduce thermal resistance and need increase back draught, back draught increases, and resistance of billet withdrawal increases, and the chance of bleedout increases greatly, so will try every possible means to reduce the resistance of throwing.The present invention proposes a kind of process that solves above-mentioned contradiction for this reason, the technology in existing gap between copper coin that promptly adopts a kind of effect by external force to change to constitute crystallizer and the copper coin solves the air gap that reduces between base shell and the crystallizer copper wall problem with the raising casting speed.Its concrete process is as follows: in the continuous casting process of billet withdrawal, molten steel is continuously to the combination mould cast with certain back draught, and in the upper and lower vibration processes of crystallizer, molten steel in crystallizer constantly heat radiation be frozen into shell and with the downward slippage of the vibration of crystallizer, form strand and skid off crystallizer, when strand upwards (because of upwards vibration of crystallizer) during slippage in combination mould, impose traversing power by copper coin wall and make existing gap smaller between the copper coin of crystallizer and the copper coin the crystallizer bottom; When strand glides in crystallizer, impose direction traversing power opposite or that minimizing is executed the copper plate of crystallizer wall and make the copper coin of crystallizer and the gap between the copper coin become big or recovery.Like this, the pressure because of external force when steel billet makes progress slippage in crystallizer makes the air gap between copper plate of crystallizer wall and the base shell reduce thermal resistance, has improved the capacity of heat transmission of crystallizer, is beneficial to the raising of casting speed; And when when strand glides because the change of external force makes the shape of crystallizer be tending towards restoring, thereby resistance of billet withdrawal is reduced, to reach the purpose that prevents bleedout; Because when steel billet makes progress relative slippage, in fact by forcing to impel the internal chamber wall of crystallizer inwardly small traversing, make existing gap smaller between the copper coin of crystallizer and the copper coin, can reduce the generation of bridging, segregation phenomena, and increase the friction of crystallizer, thereby further eliminate the transverse crack that strand may exist to steel billet.
In billet withdrawing technology of the present invention, the traversing amount of described copper plate of crystallizer is controlled in 0.005mm~0.3mm scope.
In billet withdrawing technology of the present invention, the described traversing power that the copper coin wall of crystallizer bottom is executed can machinery, hydraulic pressure, method pneumatic or Electromagnetic Drive produce.
In general, carrying out between the combination copper coin of combination mould of continuous casting billet withdrawing technology all is to have certain clearance, can carry out the continuous casting throwing by continuous casting billet withdrawing technology method of the present invention.For cooperating continuous casting billet withdrawing technology of the present invention better, the present invention has designed a kind of special combination crystallizer, the structure of this combination mould is combined into crystallizer back taper inner chamber by the polylith copper coin, its design feature is the bottom of crystallizer, measure from the lower surface of crystallizer, account for 1/3~2/3 part of whole length of mould, there is the gap between copper coin and the copper coin, the width in gap is 0.005~0.3mm, this gap under the effect of the traversing power that imposes the copper plate of crystallizer wall betwixt the crack limit inwardly do small traversing.
The present invention has designed the three kinds of combination mould new constructions that can implement above-mentioned process well, difform strands such as corresponding cast circle base, square billet and I-shaped base, according to production casting blank shape, be not limited to the structure of above-mentioned disclosed combination mould.This type of crystallizer all is to adopt combined type, constitutes combination mould by four copper coins, constitutes the structure of each copper coin of combination mould, is a kind of structure that forms cavity in vivo, and this cavity has cooling fluid input, delivery outlet, in order to import cooling fluid to cavity.By the bottom of the combination mould that each copper coin constituted, all has the described gap that can inwardly do between small traversing copper coin.
The present invention has designed several drive units that the copper coin wall of crystallizer imposed traversing power of implementing well to control in the above-mentioned crystallizer new construction simultaneously.These devices can comprise:
1, synchronous hydraulic drive unit;
2, pneumatic actuating device;
3, electromagnetic actuator device;
3, mechanical tracks constraint control device.
Different structures can adopt different control modes, also is not limited to above-mentioned disclosed control mode.
Adopt continuous casting billet withdrawing technology of the present invention and special-purpose combination mould, traditional continuous casting billet withdrawing technology has been realized effective innovation, solve the raising pulling rate effectively and prevented existing contradiction between the bleedout, can improve pulling rate, can avoid bleedout again, and have reduce to put up a bridge, the generation of segregation phenomena, and the technique effect of eliminating transverse crack that strand may exist etc.
Description of drawings
Fig. 1 is the structural representation of the combination mould of conticaster production circle base of the present invention;
Fig. 2 is that the A of Fig. 1 is to view;
Fig. 3 produces the structural representation of the combination mould of square billet for conticaster of the present invention;
Fig. 4 is the vertical view of Fig. 3;
Fig. 5 produces the structural representation of the combination mould of I-shaped base for conticaster of the present invention;
Fig. 6 is that the A of Fig. 5 is to view;
Fig. 7 is for adopting the structure chart of mechanical tracks constraint control device control combination copper plate of crystallizer transverse motion;
Fig. 8 is for adopting the structure chart of fluid pressure drive device control combination copper plate of crystallizer transverse motion;
Fig. 9 is for adopting the structure chart of electromagnetic actuator device control combination copper plate of crystallizer transverse motion;
Figure 10 is for adopting the structure chart of pneumatic actuating device control combination copper plate of crystallizer transverse motion.
The label of each accompanying drawing is represented respectively: the 1st, and crystalliser, the 2nd, copper coin, 3 is not solidified molten steel, 4 is air gap, the 5th, roller, 6 do not solidify steel billet, and the 7th, the frame (track) of control copper coin slight lateral motion; The 8th, synchronous hydraulic cylinder, the 9th, synchronous vibration cylinder up and down, the 10th, electromagnet; The 11st, laterally synchronous cylinder, the 12nd, servo valve.
The specific embodiment
Below in conjunction with accompanying drawing embodiments of the present invention are described in further detail:
Embodiment one
Present embodiment is the production embodiment that continuous casting draws the circle base, and adopting the cross section that is made of four combination copper coins 2 is circular combination mould, and its structure as shown in Figure 1 and Figure 2.The bottom of this combination mould accounts for the part of length of mould 1/2, leave the gap between the copper coin of four copper coins 2 and the copper coin, the width in gap is about 0.01mm, in the body of every copper coin cavity is arranged, this cavity is by the import and the outlet of cooling fluid, to cavity input cooling fluid.When carrying out the continuous casting billet withdrawing technology, the upper end of combination mould is fixing by crystalliser 1, this combination mould is installed on the vibrating grid, with the vibrating grid up-down vibration, continuously to crystallizer pour steel, molten steel is in the process that crystallizer glides, because the strong cooling effect of copper wall, molten steel just begins to be frozen into shell under the meniscus level, and scull is along with throwing motion decline progressive additive, and the scull cooling is shunk with the copper wall and broken away from and generation air gap 4.In process of billet withdrawal, adopt following technology: when steel billet makes progress slippage with crystallizer, the copper coin wall of crystallizer bottom is imposed inside traversing power F makes the internal chamber wall of crystallizer inwardly small traversing, even existing gap smaller between the copper coin of crystallizer and the copper coin, thereby the air gap between steel billet and the copper coin wall is diminished, improved the heat-conducting effect of crystallizer, the base shell has been solidified be tending towards even.When steel billet during in the downward slippage of crystallizer, the copper coin wall under the effect of power F, produce one outside small traversing, the resistance of throwing is reduced, prevent bleedout.In the present embodiment, adopt mechanical tracks constraint control device as shown in Figure 7 to produce the traversing power F that the copper coin wall of crystallizer bottom is executed, control combination copper plate of crystallizer transverse motion.This mechanical tracks constraint control device comprises the frame (track) 7 of control copper coin slight lateral motion, this frame (track) 7 is an inclined plane, with be installed in combination mould copper coin 2 walls on track restrained 21 match, be enclosed within for track restrained 21 on the frame (track) 7, when combination mould up and down during slippage, slide up and down at inclined plane for track restrained 21, retrained by it, produce the said traversing power F that the copper plate of crystallizer wall is executed.
Embodiment two
Present embodiment is the production embodiment that continuous casting draws square billet, and adopting the cross section that is made of four combination copper coins 2 is square combination mould, and its structure as shown in Figure 3, Figure 4.The bottom of this combination mould accounts for the part of length of mould 1/3, leave the gap between the copper coin of four copper coins 2 and the copper coin, the width in gap is about 0.02mm, in the body of every copper coin cavity is arranged, this cavity is by the import and the outlet of cooling fluid, to cavity input cooling fluid.When carrying out the continuous casting billet withdrawing technology, the upper end of combination mould is fixing by crystalliser 1, this combination mould is installed on the vibrating grid, with the vibrating grid up-down vibration.In process of billet withdrawal, adopt following technology: when steel billet makes progress slippage with crystallizer, the copper coin wall of crystallizer bottom is imposed inside traversing power F make the internal chamber wall of crystallizer inwardly small traversing; When steel billet during in the downward slippage of crystallizer, the copper coin wall under the effect of power F, produce one outside small traversing.In the present embodiment, by fluid pressure drive device as shown in Figure 8, the synchronous hydraulic cylinder 9 of employing and crystallizer up-down vibration produces the power of the horizontal synchronous hydraulic cylinder of control, produces the transverse motion that small traversing power F realizes the driven in synchronism copper coin with synchronous hydraulic cylinder 8.
Embodiment three
Present embodiment is the production embodiment that continuous casting draws the I-shaped base, and adopting the cross section that is made of four combination copper coins 2 is I-shaped combination mould, its structure such as Fig. 5, shown in Figure 6.The bottom of this combination mould accounts for the part of length of mould 2/3, leave the gap between the copper coin of four copper coins 2 and the copper coin, the width in gap is at 0.03mm, in the body of every copper coin cavity is arranged, this cavity is by the import and the outlet of cooling fluid, to cavity input cooling fluid.When carrying out the continuous casting billet withdrawing technology, the upper end of combination mould is fixing by crystalliser 1, this combination mould is installed on the vibrating grid, with the vibrating grid up-down vibration.In process of billet withdrawal, adopt following technology: when steel billet makes progress slippage with crystallizer, the copper coin wall of crystallizer bottom is imposed inside traversing power F make the internal chamber wall of crystallizer inwardly small traversing; When steel billet during in the downward slippage of crystallizer, the copper coin wall under the effect of power F, produce one outside small traversing.In the present embodiment, adopt electromagnetic actuator device as shown in Figure 9,, produce and drive the traversing electromagnetic force F of copper coin, realize transverse motion control the combination mould copper coin by the way that the coil of electromagnet 10 is directly switched on.
Embodiment four
Present embodiment is the production embodiment that continuous casting draws square billet, and adopting the cross section that is made of four combination copper coins 2 is square combination mould, and its structure as shown in Figure 3, Figure 4.The bottom of this combination mould accounts for the part of length of mould 1/2, leave the gap between the copper coin of four copper coins 2 and the copper coin, the width in gap is about 0.02mm, in the body of every copper coin cavity is arranged, this cavity is by the import and the outlet of cooling fluid, to cavity input cooling fluid.When carrying out the continuous casting billet withdrawing technology, the upper end of combination mould is fixing by crystalliser 1, this combination mould is installed on the vibrating grid, with the vibrating grid up-down vibration.In process of billet withdrawal, adopt following technology: when steel billet makes progress slippage with crystallizer, the copper coin wall of crystallizer bottom is imposed inside traversing power F make the internal chamber wall of crystallizer inwardly small traversing; When steel billet during in the downward slippage of crystallizer, the copper coin wall under the effect of power F, produce one outside small traversing.In the present embodiment, by pneumatic actuating device as shown in figure 10, adopt servo valve 12 by the control compressed air-driven laterally synchronously cylinder 11 realize control to the transverse motion of copper coin.