CN1923390A - Heat zincplating planisher roll shape curve design method - Google Patents

Abstract

The invention relates to thermal zinc plating finisher curvature design method, which comprises a, collecting device parameter of finisher, and kind standards; b, selecting right standard, to fix the weight factor of each standard; c, designing the roller curvature formula and optimizing the curvature parameters; d, adding said parameter into roller curvature formula to obtain optimized formula. The invention uses pre-discharge tension stress and rolling pressure transverse distribution uniformity as target function, to optimize the working roller and support roller curvatures, to support the stability and uniformity of zinc layer.

Description

Heat zincplating planisher roll shape curve design method

Technical field

The present invention relates to a kind of rolling technique of hot-dip galvanizing sheet steel, particularly a kind of heat zincplating planisher roll shape curve design method.

Background technology

Existing planisher roll design technology generally only considers that the preceding tensile stress cross direction profiles of band is even, and promptly exit plate shape is good.But for the smooth unit of galvanizing, according to its characteristic, the strip shape quality of only considering product is not enough, also must consider the stability of zinc layer in the formation process and zinc flower uniformity, avoid problem such as surface chromatic aberration.

Summary of the invention

Purpose of the present invention is to provide a kind of heat zincplating planisher roll shape curve design method, makes this planisher not only can satisfy the plate shape requirement of product, can also satisfy the stability of zinc layer in the formation process and the technological requirements such as uniformity of zinc flower.

To achieve these goals, the present invention has adopted following technical scheme: a kind of heat zincplating planisher roll shape curve design method may further comprise the steps:

The description scope of a, the device parameter of collecting planisher and band steel;

The representative specification is chosen in b, the thickness according to product, width, strength grade combination, and determines respectively to represent the weight coefficient of specification according to each ratio of representing the close specification of specification and representative thereof to account for the unit total output;

C, with a, b, k, l _z, δ is the roller curve parameter and optimizes variable that the roller curve equation of setting working roll is:

D _w(x)＝D _w-a{1-cos[bπ(2x/L _w)]}/[1-cos(bπ)]

The roller curve equation of setting backing roll is:

$D_b\left(x\right)=\left\{\begin{array}{cc}{D}_b& \left|x\right|\≤(L_b/2-l_z)\\ D_b-2\mathrm{\δ}{\left(\frac{\left|x\right|-(L_b/2-l_z)}{l_z}\right)}^k& \left|x\right|>(L_b/2-l_z)\end{array}\right.$

In above-mentioned two formulas:

D _W-working roll green diameter (mm);

L _W-working roll barrel length (mm);

D _b-backing roll green diameter (mm);

L _b-backing roll barrel length (mm);

A-work roll crown coefficient;

B-working roll cosine phase coefficient;

l _Z-backing roll roller curve bending section length (mm);

δ-backing roll roller curve bending section height (mm);

Calculate the roller curve parameter by following optimization order:

1), given initial curve parameter X ₀=[a, b, k, l _z, δ];

2), calculate plate shape and the draught pressure distribution Comprehensive Control objective function F of ideal format product j _j(X);

3), calculate roll shape objective function of optimization design function G (X);

4), judge whether the Powell condition is set up, if be false, repeat above-mentioned steps 2) and 3), set up until the Powell condition, finish calculating, draw optimum roller curve parameter;

The roller curve equation of d, the working roll after the roller curve equation of the roller curve equation of above-mentioned roller curve parameter substitution working roll and backing roll is optimized and the roller curve equation of backing roll.

The device parameter of described planisher comprises: working roll barrel length L _W, work roll diameter D _W, backing roll barrel length L _b, backing roll diameter D _b, backing roll transmission side and active side housing screw centre-to-centre spacing l ₁, the positive and negative roller of working roll, transmission side and active side roller hydraulic cylinder centre-to-centre spacing l ₂, maximum bending roller force S, maximum draught pressure P, maximum mill speed V;

The description scope of described band steel comprises strip width B, thickness h, yield strength σ _sWith smooth percentage elongation ε.

Plate shape described in the step c and draught pressure distribution Comprehensive Control object function are defined as:

F _j(X)＝α*g ₁(X)+(1-α)*g ₂(X)

In the formula:

g ₁(X) representative outlet forward pull index, g ₁(X)=(max (σ _1i)-min (σ _1i))/σ ₁

g ₂(X) represent the cross direction profiles uniformity index of draught pressure, g ₂(X)=(max (q _i)-min (q _i))/q;

α-weight coefficient generally speaking, is got α=0.35;

J-j kind is represented specification;

-average preceding tensile stress:

The q-average roll pressure;

σ _1iTensile stress cross direction profiles value before the-unit width band steel;

q _i-unit width draught pressure cross direction profiles value.

Roll shape objective function of optimization design function definition described in the step c is:

$G\left(X\right)=\underset{j=1}{\overset{m}{\mathrm{\Σ}}}{\mathrm{\β}}_j{F}_j\left(X\right)$

In the formula:

β _j-weight coefficient is determined by the ratio of production output in total output of each specification product.

The basic principle of heat zincplating planisher roll shape curve design method of the present invention is as follows:

According to metal rolled Deformation Theory as can be known, the front and back tension force σ of band in the operation of rolling _1i, σ _0iThe function representation of difference available formula (1) and formula (2):

σ _1i＝f ₁(h _i，H _i，L _i，B，T ₀，T ₁) (1)

σ _0i＝f ₀(h _i，H _i，L _i，B，T ₀，T ₁) (2)

In the formula: h _i-band exit thickness cross direction profiles value;

H _iThe thickness cross direction profiles value of-band supplied materials;

L _i-expression comes the length cross direction profiles value of flitch shape;

The width of B-band;

T ₀-average backward pull;

T ₁-average forward pull.

Equally, according to the roll elastic deformation model in the document plate shape theory (referring to document: Lian Jiachuan, Liu Hongmin, gauge and shape control, Beijing: weapon industry publishing house, 1995) as can be known, for the exit thickness distribution value h that rolls the back band _iCan use the function representation of formula (3):

h _i＝f ₃( H，T ₀，T ₁， ε，S，X，H _i，σ _1i，σ _0i) (3)

In the formula: the total draught pressure of P-;

The S-bending roller force;

The average thickness of H-band supplied materials;

ε-setting percentage elongation.

Like this, for a specific operation of rolling, band supplied materials parameter such as H, H _i, L _i, B etc. are known, if given T ₀, T ₁, ε, S, simultaneous formula (1)-(3) can be with the forward pull cross direction profiles value σ of characterization board shape _1iWith a working roll and backing roll roll forming parameter X is that the function of independent variable is represented, that is:

σ _1i＝f ₄(X) (4)

σ _0i＝f ₅(X) (5)

Meanwhile, according to relevant draught pressure model (a kind of draught pressure computational methods are referring to document: Lian Jiachuan. the calculating of cold rolling sheet rolling pressure and limit minimum thickness. heavy-duty machinery. the 2nd, 3 phase .1979) can know draught pressure cross direction profiles q _iCan represent with following formula:

q _i＝f ₆(H _i，h _i，σ _1i，σ _0i) (6)

Composite type (1)-(5) can be (6) formula that the function of independent variable is represented with one with working roll and backing roll roll forming parameter X also, that is:

q _i＝f ₇(X) (7)

According to Field Research and analysis, for the galvanizing planisher, carry out smoothly in order to make production, not only to guarantee plate shape precision, and will satisfy the requirement that draught pressure is evenly distributed, with the stability of zinc layer in the assurance formation process and the uniformity of zinc flower.Like this, plate shape in the production process and draught pressure Comprehensive Control object function can simply be defined as:

F _j(X)＝α*g ₁(X)+(1-α)*g ₂(X) (8)

In the formula:

g ₁(X)＝(max(σ _1i)-min(σ _1i))/T ₁ (9)

g ₂(X)＝(max(q _i)-mi(q _i))/q (10)

The q-average roll pressure;

α-weight coefficient, generally speaking α=0.35

G in formula (8) ₁(X) represent plate shape index, and g ₂(X) then represent the cross direction profiles uniformity index of roll gap pressure.

Because for the galvanizing planisher, the purpose of roller curve design is by designing a kind of suitable working roll and backing roll roll shape, make roll when as-rolled condition, for the product of all specifications (in actual production, the general product of frequent m specification of producing of selecting is optimized, and should be weighted according to the ratio in each comfortable total output, the frequent product of producing, weight coefficient is obtained big more), plate shape and draught pressure Comprehensive Control objective function F (X) minimum, so roll shape objective function of optimization design function can be expressed as:

$G\left(X\right)=\underset{j=1}{\overset{m}{\mathrm{\Σ}}}{\mathrm{\β}}_j{F}_j\left(X\right)---\left(11\right)$

β in the formula _j-weight coefficient is determined by the ratio of production output in total output of each specification product.

Like this, whole roller curve optimal design process can simply be described as: seek a suitable working roll and backing roll roll shape parameter X={ a, b, k, l _z, δ }, make G (X) minimum, calculation process as shown in Figure 1, working roller curve is as shown in Figure 2; Backing roll roller curve schematic diagram as shown in Figure 3.

Need to prove that in the roll design process, should the make even mean value of complete machine roller ability maximum and minimum of a value of bending roller force can make bending roller force that enough up-down adjustment scopes are arranged like this, improves the control ability of bending roller force in the operation of rolling.The assembly average that band supplied materials convexity and plate shape are then got this specification product.

The present invention fully takes into account the process characteristic of galvanizing planisher, all evenly as object function planisher working roll and backing roll roller curve is carried out Synthetical Optimization with tensile stress and draught pressure cross direction profiles before the band outlet first.Make the roll shape after optimizing to satisfy the plate shape requirement of product, can also satisfy the stability of zinc layer in the formation process and the technological requirements such as uniformity of zinc flower.

This method is equally applicable to the smooth of some other band steel that surface uniformity and plate shape are had relatively high expectations.

Description of drawings

Fig. 1 is the roller curve Optimal design and calculation flow chart among the present invention;

Fig. 2 is the working roller curve schematic diagram according to roller curve equation design of the present invention;

Fig. 3 is the backing roll roller curve schematic diagram according to roller curve equation design of the present invention;

Fig. 4 is the draught pressure calculation flow chart that adopts among the present invention;

Fig. 5 is best bending roller force and toe-out stress distribution (exit plate shape) calculation flow chart (referring to document: Lian Jiachuan, Liu Hongmin, gauge and shape control, Beijing: weapon industry publishing house, 1995) that adopts among the present invention;

Fig. 6 is the band hypothesis supplied materials convexity distribution map of specification one;

Fig. 7 is before roll shape is optimized, the plate shape curve of the band of specification one under different bending roller forces;

Fig. 8 is after roll shape is optimized, the plate shape curve of the band of specification one under different bending roller forces;

Fig. 9 is before roll shape is optimized, the draught pressure cross direction profiles of the band of specification one under best bending roller force (36 tons);

Figure 10 is after roll shape is optimized, the draught pressure cross direction profiles of the band of specification one under best bending roller force (18 tons);

Figure 11 is the band hypothesis supplied materials convexity distribution map of specification two;

Figure 12 is before roll shape is optimized, the plate shape curve of the band of specification two under different bending roller forces;

Figure 13 is after roll shape is optimized, the plate shape curve of the band of specification two under different bending roller forces;

Figure 14 is before roll shape is optimized, the draught pressure cross direction profiles of the band of specification two under best bending roller force (24.6 tons);

Figure 15 is after roll shape is optimized, the draught pressure cross direction profiles of the band of specification two under best bending roller force (8.4 tons).

The specific embodiment

Below provided and adopted the inventive method to optimize the design process and the result of calculation of a certain planisher roller curve:

(1), calculate required equipment, product mix raw data associated:

Planisher device parameter: working roll barrel length L _w=1500mm, work roll diameter D _w=φ 480/520mm, backing roll barrel length L _b=1450mm, backing roll diameter D _b=φ 1150/1250mm, backing roll transmission side and active side housing screw centre-to-centre spacing l ₁=2.67m, the positive and negative roller of working roll, transmission side and active side roller hydraulic cylinder centre-to-centre spacing l ₂=2.47m.Maximum bending roller force ± 60t, maximum draught pressure 700t, maximum mill speed 180m/min, wet smooth.

Product variety specification limit: strip width 800～1250mm, thickness 0.20～1.3mm, yield strength σ _s280～620Mpa, smooth percentage elongation 0.5～1.5%.

(2) on behalf of specification, roll shape optimization typical case choose

Choose 8 kinds and represent specification according to product thickness, width, strength grade combination, and determine respectively to represent the weight coefficient β of specification according to each ratio of representing the output of the close specification of specification and representative thereof to account for the unit total output _jConcrete data are as shown in table 1.

Table 1,

Sequence number	Thickness (mm)	Width (m)	Yield strength (MPa)	Weight coefficient β j(％)
					1	0.25	1.20	300	17.0
2	0.25	0.80	300	13.0
					3	0.25	1.20	600	17.0
4	0.25	0.80	600	18.0
					5	1.20	1.20	300	22.0
6	1.20	0.80	300	13.0
					7	1.20	1.20	600	18.0
8	1.20	0.80	600	22.0

(3) the roller curve parameter optimization is calculated

Backing roll is plain-barreled roll, work roll crown 0.06mm before the roll shape optimization.Get the initial curve parameter X ₀=[a, b, k, l _z, δ]=[0.06,0.3,0,1.0,0.0].

Optimize each time in the iterative computation process, call draught pressure calculation process shown in Figure 4 and obtain total draught pressure P, call best bending roller force shown in Figure 5 and toe-out stress distribution (exit plate shape) calculation process and obtain being with the preceding tensile stress cross direction profiles value σ of steel _1iWith draught pressure cross direction profiles value q _i

The Powell optimization is set up condition:

‖G _n(X)-G _n-1(X)‖≤ε‖G _n-1(X)‖

G in the formula _n(X)-when the target function value of iteration last time

G _N-1(X)-target function value of a preceding iteration

ε-convergence control coefrficient gets 10 ^-2

Satisfy and obtain optimum roll shape parameter after the optimization establishment condition:

X＝[a，b，k，l _z，δ]＝[0.05，0.183，4，147.0，1.1]。

Working roller curve equation after promptly optimizing is:

D _w(x)＝520-0.311×[1-cos(0.00076616x)]

Backing roll roller curve equation is:

$D_b\left(x\right)=\left\{\begin{array}{cc}1250& \left|x\right|\≤578\\ 1250-2.2\×{\left(\frac{\left|x\right|-578}{147}\right)}^4& \left|x\right|>578\end{array}\right.$

Effect after the roller curve optimization can be illustrated in exit plate shape and draught pressure cross direction profiles analog case before and after the roll shape optimization by following two kinds of specification bands.

Specification one, 0.22mm * 1250mm set percentage elongation 1.0%, resistance of deformation 600Mpa, total draught pressure 531t.

The supplied materials convexity as shown in Figure 6.

Before roller curve was optimized, the plate shape simulation under different bending roller forces as shown in Figure 7.

After roll shape was optimized, the plate shape simulation under different bending roller forces as shown in Figure 8.

Before the roller curve, the draught pressure cross direction profiles of (36 tons) as shown in Figure 9 under the best bending roller force condition.

After roll shape was optimized, the draught pressure cross direction profiles of (18 tons) as shown in figure 10 under the best bending roller force.

Fig. 7～Figure 10 has provided exit plate shape, the draught pressure cross direction profiles analog result of this specification before and after roll shape is optimized respectively: the best bending roller force 18t after roll shape is optimized, corresponding exit plate shape 1.6I, draught pressure cross direction profiles scope 92450～95750N/20mm; Best bending roller force 36t before optimizing, corresponding exit plate shape 6.6I, draught pressure cross direction profiles scope 9200～96050N/20mm.Reach a conclusion thus: strip shape quality after this specification roll shape optimization is improved, and best bending roller force descends 47.6%, and the draught pressure cross direction profiles is more even.

Specification two, 0.58mm * 1250mm set percentage elongation 1.0%, resistance of deformation 600Mpa, total draught pressure 363t.

The supplied materials convexity as shown in figure 11.

Before roller curve was optimized, the plate shape analog result under different bending roller forces as shown in figure 12.

After roller curve was optimized, the plate shape analog result under different bending roller forces as shown in figure 13.

Before roller curve was optimized, the draught pressure cross direction profiles of (24.6 tons) as shown in figure 14 under the best bending roller force.

After roller curve was optimized, the draught pressure cross direction profiles of (8.4 tons) as shown in figure 15 under the best bending roller force.

Figure 12～Figure 15 has provided this specification respectively in roll shape optimization exit plate shape, draught pressure cross direction profiles analog result thereafter: the best bending roller force 8.4t after roll shape is optimized, corresponding exit plate shape 2.3I, draught pressure cross direction profiles scope 61350～63600N/20mm; Best bending roller force 24.6t before optimizing, corresponding exit plate shape 3.1I, draught pressure cross direction profiles scope 61150～63750N/20mm.Reach a conclusion thus: strip shape quality after this specification roll shape optimization is improved, and best bending roller force descends 74.0%, and the draught pressure cross direction profiles is more even.

Claims (4)

1, a kind of heat zincplating planisher roll shape curve design method is characterized in that: may further comprise the steps:

The description scope of a, the device parameter of collecting planisher and band steel;

The representative specification is chosen in b, the thickness according to product, width, strength grade combination, and determines respectively to represent the weight coefficient of specification according to each ratio of representing the close specification of specification and representative thereof to account for the unit total output;

C, with a, b, k, l _z, δ is the roller curve parameter and optimizes variable that the roller curve equation of setting working roll is:

D _w(x)＝D _w-a{1-cos[bπ(2x/L _w)]}/[1-cos(bπ)]

The roller curve equation of setting backing roll is:

$D_b\left(x\right)=\left\{\begin{array}{cc}{D}_b& \left|x\right|\≤(L_b/2-l_z)\\ D_b-2\mathrm{\δ}{\left(\frac{\left|x\right|-(L_b/2-l_z)}{l_z}\right)}^k& \left|x\right|>(L_b/2-l_z)\end{array}\right.$

In above-mentioned two formulas:

D _W-working roll green diameter (mm);

L _W-working roll barrel length (mm);

D _b-backing roll green diameter (mm);

L _b-backing roll barrel length (mm);

A-work roll crown coefficient;

B-working roll cosine phase coefficient;

l _Z-backing roll roller curve bending section length (mm);

δ-backing roll roller curve bending section height (mm);

Calculate the roller curve parameter by following optimization order:

1), given initial curve parameter X ₀=[a, b, k, l _z, δ];

2), calculate plate shape and the draught pressure distribution Comprehensive Control objective function F of ideal format product j _j(X);

3), calculate roll shape objective function of optimization design function G (X);

4), judge whether the Powell condition is set up, if be false, repeat above-mentioned steps 2) and 3), set up until the Powell condition, finish calculating, draw optimum roller curve parameter;

The roller curve equation of d, the working roll after the roller curve equation of the roller curve equation of above-mentioned roller curve parameter substitution working roll and backing roll is optimized and the roller curve equation of backing roll.

2, heat zincplating planisher roll shape curve design method according to claim 1 is characterized in that: the device parameter of described planisher comprises: working roll barrel length L _W, work roll diameter D _W, backing roll barrel length L _b, backing roll diameter D _b, backing roll transmission side and active side housing screw centre-to-centre spacing l ₁, the positive and negative roller of working roll, transmission side and active side roller hydraulic cylinder centre-to-centre spacing l ₂, maximum bending roller force S, maximum draught pressure P, maximum mill speed V;

The description scope of described band steel comprises strip width B, thickness h, yield strength σ _sWith smooth percentage elongation ε.

3, heat zincplating planisher roll shape curve design method according to claim 1 is characterized in that: plate shape described in the step c and draught pressure distribution Comprehensive Control object function are defined as:

F _j(X)＝α*g ₁(X)+(1-α)*g ₂(X)

In the formula:

g ₁(X) representative outlet toe-out stress index, g ₁(X)=(max (σ _1i)-min (σ _1i))/σ ₁

g ₂(X) represent the cross direction profiles uniformity index of draught pressure, g ₂(X)=(max (q _i)-min (q _i))/q; α-weight coefficient generally speaking, is got α=0.35;

J-j kind is represented specification;

σ ₁-average preceding tensile stress;

The average unit width draught pressure of q-;

σ _1iTensile stress cross direction profiles value before the-band steel;

q _i-unit width draught pressure cross direction profiles value.

4, heat zincplating planisher roll shape curve design method according to claim 1 is characterized in that: the roll shape objective function of optimization design function definition described in the step c is:

$G\left(X\right)=\underset{j=1}{\overset{m}{\mathrm{\Σ}}}{\mathrm{\β}}_j{F}_j\left(X\right)$

In the formula:

β _j-weight coefficient is determined by the ratio of production output in total output of each specification product.

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