CN104128576A - Method and device for obtaining continuous taper of lower datum parabola of crystallizer - Google Patents

Abstract

The invention belongs to the field of steel making continuous casting and provides a method and device for obtaining the continuous taper of a lower datum parabola of a crystallizer. The method comprises the steps that the taper at the position of a lower opening of the crystallizer is worked out; the total taper in the length direction of the crystallizer is worked out; according to the taper at the position of the lower opening of the crystallizer and the total taper, the taper at any position away from the lower opening in the length direction is worked out. According to the crystallizer manufactured by the adoption of the method and device for obtaining the continuous taper of the lower datum parabola of the crystallizer, an inner casting blank and the wall surface of the crystallizer are in good contact with each other at any position, high heat transfer efficiency between the casting blank and the crystallizer is achieved, in this way, the quality of a casting blank is improved, the casting speed is increased, and an important guarantee is provided for efficient continuous casting.

Description

The continuous tapering acquisition methods of benchmark parabola and device under a kind of crystallizer

Technical field

The invention belongs to steel-making continuous casting field, relate in particular to the continuous tapering acquisition methods of benchmark parabola and device under a kind of crystallizer.

Background technology

Crystallizer is the heart of conticaster, is the core of crystallizer design process and formulate conical degree of crystallizer, and the reasonability of its formulation is directly determining the attainable pulling rate scope of conticaster and the slab quality of casting.If conical degree of crystallizer arranges too smallly, can make the easy air gap that produces between base shell and crystallizer wall, thereby affect the heat transfer between strand and crystallizer, cause the inhomogeneous growth of base shell in crystallizer, the air gap that the inhomogeneities of this shell growth process can be aggravated between base shell and crystallizer wall conversely produces, and then produces slab qualities such as Longitudinal Surface Cracks problem; If conical degree of crystallizer arranges too much, can aggravate the wearing and tearing to copper plate of crystallizer, increase resistance of billet withdrawal simultaneously, and then produce slab qualities such as surperficial transverse fissure problem; And all these are because tapering arranges, the unreasonable impact bringing all can produce restriction to casting speed.For this reason, reasonably formulate the tapering of crystallizer in casting process and have the realistic meaning of highly significant.

Summary of the invention

In view of the above problems, the object of the present invention is to provide the continuous tapering acquisition methods of benchmark parabola and device under a kind of crystallizer, be intended to solve in prior art scheme due to tapering arrange improper, make base shell and the loose contact of crystallizer wall of strand in crystallizer good, affect the technical problem of slab quality.

On the one hand, under described crystallizer, the continuous tapering acquisition methods of benchmark parabola comprises the steps:

Calculate crystallizer end opening position tapering;

Calculate total tapering of length of mould direction;

According to described end opening position tapering and total tapering, calculate at length direction the tapering apart from end opening any position.

On the other hand, under described crystallizer, the continuous tapering acquisition device of benchmark parabola comprises:

End opening tapering computing unit, for calculating crystallizer end opening position tapering;

Total tapering computing unit, for calculating total tapering of length of mould direction;

Tapering distribution computing unit, uses according to described end opening position tapering and total tapering, calculates at length direction the tapering apart from end opening any position.

The invention has the beneficial effects as follows: the theoretical foundation that the present invention is based on the process of billet withdrawal of hot-cast base in crystallizer, taking the total tapering in length of mould direction as starting point, obtain the continuous cast mold of the continuous tapering of benchmark parabola, in crystallizer, the base shell of strand and crystallizer wall what position in office all keeps good contact, realize heat transfer efficiency high between strand and crystallizer, thereby improve slab quality, promoted casting speed, provide important guarantee for realizing high efficiency continuous casting.

Brief description of the drawings

Fig. 1 is the flow chart of the continuous tapering acquisition methods of benchmark parabola under the crystallizer that provides of the embodiment of the present invention;

Fig. 2 is the crystallizer vertical profile structure chart that the embodiment of the present invention provides;

Fig. 3 is apart from crystallizer end opening position and crystallizer internal cavity length of side S in example one _xcurve relation figure;

Fig. 4 is apart from crystallizer end opening position and crystallizer internal cavity length of side S in example two _xcurve relation figure;

Fig. 5 is the block diagram of the continuous tapering acquisition device of benchmark parabola under the crystallizer that provides of the invention process.

Detailed description of the invention

In order to make object of the present invention, technical scheme and advantage clearer, below in conjunction with drawings and Examples, the present invention is further elaborated.Should be appreciated that specific embodiment described herein, only in order to explain the present invention, is not intended to limit the present invention.

For technical solutions according to the invention are described, describe below by specific embodiment.

Fig. 1 shows the continuous tapering acquisition methods of benchmark parabola flow process under the crystallizer that the embodiment of the present invention provides, and only shows for convenience of explanation the part relevant to the embodiment of the present invention.

Under the crystallizer that the present embodiment provides, the continuous tapering acquisition methods of benchmark parabola comprises the steps:

Step S101, calculating crystallizer end opening position tapering;

Total tapering of step S102, calculating length of mould direction.

With reference to the crystallizer vertical profile structure shown in Fig. 2, and set up XYZ coordinate system according to diagram, the selection of the origin of coordinates should make the T trying to achieve ₂meet the solidification shrinkage characteristic of current cast steel grade in crystallizer with the value of T.Meet square root law according to casting blank solidification, and crystallizer change in size and strand contraction phase are worked as, and the expression formula that can obtain crystallizer end opening position tapering and total tapering according to the definition of conical degree of crystallizer is respectively as shown in formula (1) and formula (2):

$T_2=\frac{4{\mathrm{kx}}_1}{b}\×{10}^5---\left(1\right)$

$T=\frac{2k(x_2^2-x_1^2)}{\mathrm{bL}}\×{10}^5---\left(2\right)$

Wherein k is steel grade coefficient, conventionally gets 0～5mm ^-1, b is the crystallizer end opening length of side, x ₁for crystallizer end opening coordinate, x ₂for crystallizer coordinate suitable for reading, L is crystallizer total length.

Step S103, according to described end opening position tapering and total tapering, calculate at length direction the tapering apart from end opening any position.

Can be obtained by formula (1):

$k=\frac{T_{2}b}{4x_1}\×{10}^{-5}---\left(3\right)$

In addition, there is geometrical relationship:

L＝x ₂-x ₁ (4)

Can obtain in conjunction with formula (2) and formula (3):

$x_2+x_1=\frac{2T}{T_2}{x}_1---\left(5\right)$

Can obtain thus:

$\frac{x_1}{x_2}=\frac{T_2}{2T-T_2}---\left(6\right)$

Simultaneous formula (4) and formula (6), can obtain:

$x_1=\frac{T_{2}L}{2(T-T_2)},x_2=\frac{(2T-T_2)L}{2\left(T{-T}_2\right)}---\left(7\right)$

Substitution formula (3), can obtain:

$k=\frac{b(T-T_2)}{2L}\×{10}^{-5}---\left(8\right)$

According to the definition of conical degree of crystallizer, in conjunction with formula (7) and formula (8), the tapering Tx that can obtain any position in crystallizer is:

$\begin{array}{c}{T}_x=\frac{2k({(x_1+x+\mathrm{\Δx})}^2-{(x_1+x)}^2)}{b(x_1+x+\mathrm{\Δx}-x_1-x)}\×{10}^5=\frac{2k}{b}\frac{{(x_1+x+\mathrm{\Δx})}^2-{(x_1+x)}^2}{\mathrm{\Δx}}\×{10}^5\\ =\frac{4k(x_1+x)}{b}\×{10}^5=\frac{2(T-T_2)}{L}(\frac{T_{2}L}{2(T-T_2)}+x)\\ =\frac{2(T-T_2)x}{L}+T_2\end{array}---\left(9\right)$

Finally distribute according to the continuous tapering of length of mould direction, make corresponding crystallizer.In the time using this crystallizer to carry out steel-making continuous casting, in crystallizer, the base shell of strand and crystallizer wall what position in office all keeps good contact, realize heat transfer efficiency high between strand and crystallizer, thereby improve slab quality, promote casting speed, provide important guarantee for realizing high efficiency continuous casting.

Be further used as preferably, this implementation method also comprises the steps:

Step S104, according to described end opening position tapering and total tapering, calculate at length direction the crystallizer internal cavity length of side apart from end opening any position.

In step S103, calculate the tapering distribution of crystallizer in the longitudinal direction according to the end opening position tapering obtaining and total tapering, can distribute and determine the structure of crystallizer by tapering.Can certainly distribute and determine the structure of crystallizer by the inner chamber length of side of crystallizer.In this preferred steps, calculate the crystallizer internal cavity length of side by end opening position tapering and total tapering and distribute.

According to formula (7) and (8) can calculate apart from crystallizer end opening distance for the inner chamber length of side Sx at x place as follows:

$\begin{array}{c}{S}_x=b+2k({(x+x_1)}^2-{x_1}^2)\\ =b(1+\frac{T-T_2}{L}({(x+\frac{T_{2}L}{2(T-T_2)})}^2-{\left(\frac{T_{2}L}{2(T-T_2)}\right)}^2)\×{10}^{-5})\\ =b(1+\frac{1}{L}((T-T_2)x^2+T_2\mathrm{Lx})\×{10}^{-5})\end{array}---\left(10\right)$

Provide two concrete calculated examples below.

Example one:

Casting high-carbon steel, the square billet that casting blank specification is 200mm × 200mm, length of mould is 900mm, and crystallizer bottom size is 201.4mm, and crystallizer end opening position is 225mm.

L=900mm as the above analysis, b=201.4mm, x ₁=225mm, x ₂=1125mm; Correspondingly get k=7.683 × 10 ^-7mm ^-1.

1.1 calculate crystallizer end opening position tapering T ₂:

$T_2=\frac{4{\mathrm{kx}}_1}{b}\×{10}^5=0.3433\%/m;$

1.2 calculate the total tapering T in length of mould direction:

$T=\frac{2k(x_2^2-x_1^2)}{\mathrm{bL}}\×{10}^5=1.03\%/m;$

1.3 calculate the crystallizer internal cavity length of side S apart from end opening any position x _x:

S _x＝201.4+1.537×10 ^-6x ²+6.915×10 ^-4x mm；

1.4 calculate the tapering T apart from end opening any position x _x:

T _x＝0.001526x+0.3433％/m；

Apart from crystallizer end opening position and crystallizer internal cavity dimensions length S _xcurved line relation as shown in Figure 3.

Example two:

Cast alloys steel, the square billet that casting blank specification is 600mm × 600mm, length of mould is 900mm, and crystallizer bottom size is 604.2mm, and crystallizer end opening position is 225mm.

As the above analysis, L=900mm, b=604.2mm, x ₁=225mm, x ₂=1125mm; Correspondingly get k=2.685 × 10 ^-6mm ^-1.

2.1 calculate crystallizer end opening position tapering T ₂:

$T_2=\frac{4{\mathrm{kx}}_1}{b}\×{10}^5=0.4\%/m;$

2.2 calculate the total tapering T in length of mould direction:

$T=\frac{2k(x_2^2-x_1^2)}{\mathrm{bL}}\×{10}^5=1.2\%/m;$

The 2.3 crystallizer internal cavity length of side S apart from end opening any position x _x:

S _x＝604.2+5.371×10 ^-6x ²+2.417×10 ^-3xmm；

2.4 calculate the tapering T apart from end opening any position x _x:

T _x＝0.001778x+0.4％/m。

Apart from crystallizer end opening position and crystallizer internal cavity dimensions length S _xcurved line relation as shown in Figure 4.

In addition, as shown in Figure 5, the embodiment of the present invention also provides the continuous tapering acquisition device of benchmark parabola under a kind of crystallizer, comprising:

End opening tapering computing unit 31, for calculating crystallizer end opening position tapering;

Total tapering computing unit 32, for calculating total tapering of length of mould direction;

Tapering distribution computing unit 33, uses according to described end opening position tapering and total tapering, calculates at length direction the tapering apart from end opening any position.

Preferably, described device also comprises:

Inner chamber length of side computing unit 34, for according to described end opening position tapering and total tapering, calculates at length direction the crystallizer internal cavity length of side apart from end opening any position.

Wherein, described crystallizer end opening position tapering wherein k is steel grade coefficient, and b is the crystallizer end opening length of side, x ₁for crystallizer end opening coordinate.

Total tapering of described length of mould direction wherein x ₂for crystallizer coordinate suitable for reading, L is crystallizer total length.

The described tapering apart from end opening any position wherein x is the distance length from end opening at length direction; The described crystallizer internal cavity length of side apart from end opening any position $S_x=b(1+\frac{1}{L}(\left({T-T}_2\right)x^2+T_2\mathrm{Lx})\×{10}^{-5}).$

The foregoing is only preferred embodiment of the present invention, not in order to limit the present invention, all any amendments of doing within the spirit and principles in the present invention, be equal to and replace and improvement etc., within all should being included in protection scope of the present invention.

Claims (8)

1. the continuous tapering acquisition methods of benchmark parabola under crystallizer, is characterized in that, described method comprises:

Calculate crystallizer end opening position tapering;

Calculate total tapering of length of mould direction;

According to described end opening position tapering and total tapering, calculate at length direction the tapering apart from end opening any position.

2. method as claimed in claim 1, is characterized in that, described method also comprises:

According to described end opening position tapering and total tapering, calculate at length direction the crystallizer internal cavity length of side apart from end opening any position.

3. method as claimed in claim 2, is characterized in that described crystallizer end opening position tapering wherein k is steel grade coefficient, and b is the crystallizer end opening length of side, x ₁for crystallizer end opening coordinate.

4. method as claimed in claim 3, is characterized in that total tapering of described length of mould direction wherein x ₂for crystallizer coordinate suitable for reading, L is crystallizer total length.

5. method as claimed in claim 4, is characterized in that the described crystallizer internal cavity length of side apart from end opening any position wherein x is the distance length from end opening at length direction.

6. method as claimed in claim 4, is characterized in that the described tapering apart from end opening any position wherein x is the distance length from end opening at length direction.

7. the continuous tapering acquisition device of benchmark parabola under crystallizer, is characterized in that, described device comprises:

End opening tapering computing unit, for calculating crystallizer end opening position tapering;

Total tapering computing unit, for calculating total tapering of length of mould direction;

Tapering distribution computing unit, uses according to described end opening position tapering and total tapering, calculates at length direction the tapering apart from end opening any position.

8. install as claimed in claim 7, it is characterized in that, described device also comprises:

Inner chamber length of side computing unit, for according to described end opening position tapering and total tapering, calculates at length direction the crystallizer internal cavity length of side apart from end opening any position.