CN102886380B - Skin pass rolling method of negative roller for soft steel - Google Patents

Abstract

The invention provides a skin pass rolling method of a negative roller for soft steel, and is characterized in that through taking out an original support roller of a UCM (Universal Crown Mill) planishing mill, a four-roller planishing mill with the moved support roller is formed, so that when the mill is at a small rolling pressure, a bounce curve is still kept in a linear region, and meanwhile, the mill is matched with a working roller bender to control through play of the support roller, the stable precise control of flatness is realized while the rolling pressure and the uniformity coefficient of transverse distribution of the pressure between rollers are improved, the surface quality of rolled band steel is improved, the service life of the rollers is prolonged, and the product range is expanded.

Description

Be suitable for the negative roller skin pass rolling method of soft steel

Technical field

The present invention relates to soft steel skin pass rolling technology, relate in particular to a kind of negative roller skin pass rolling method that is suitable for soft steel.

Background technology

Rolled piece is in milling train when rolling, draught pressure P can cause the longitudinal elasticity distortion of the inner stressed member of work housing, and the relation curve between work housing strain f and draught pressure P is referred to as milling train strain curve or spring curve (seeing Fig. 1).The slope of milling train strain is called the stiffness coefficient K of milling train, mill modulus is larger, and the inclination alpha of straight line is larger, and the linearity range slope of strain curve is just larger.Due to the beginning section at spring curve (in little draught pressure region), the elastic deformation amount of milling train and draught pressure are non-linear relation between changing, and in the time that draught pressure exceedes a certain value, both are linear, obey Hooke's law.Within the scope of little draught pressure, because the parts such as roll, frame, screwdown gear have gap and the deformation state of parts in little contact, not exclusively obey Hooke's law.

In actual production control, bring the inconvenience of control and be difficult for determining exactly that because parts exist gap real roll gap zero-bit affects the shortcomings such as the precision of roll gap in order to overcome the variation of stiffness coefficient K, in most of the cases, milling train is generally all operated in the straightway of elastic curve, making stiffness coefficient is a constant, give to control to apply to bring convenience, in addition, in control procedure, guarantee that draught pressure is greater than pre-throw-on pressure P ₀(its value should be greater than the draught pressure of non-linear section), can effectively reduce the impact in the gap between parts, thereby can greatly improve frame roll gap degree of regulation.

For six roller UCM planishing mills (being omnipotent convexity planishing mill), because its stiffness coefficient is better, the hard band of isogonic in being relatively applicable to producing.And for the smooth production of little percentage elongation of soft steel, the problem such as this milling train exists the exit plate shape of band and mechanical performance not to reach desired required precision, and product quality is wayward.Its reason is, compared with common steel grade, soft steel rolling pressure ratio is lower.If adopt six larger roller planishers of rigidity, in the time that draught pressure is very little, mill spring curve is in inelastic region, and mill stiffness is not constant, and rolling is unstable, and elongation control precision is not easy to ensure.Meanwhile, because draught pressure is less, roller strengthens the sensitivity of plate shape, and plate shape is unstable, and draught pressure and roll gap pressure cross direction profiles are inhomogeneous, and it is more difficult to control.

Summary of the invention

For the above-mentioned shortcoming existing in prior art, the object of this invention is to provide a kind of negative roller skin pass rolling method that is suitable for soft steel, can utilize six-high cluster mill to carry out the rolling of soft steel, to realize its product scope of expansion.

Particularly, the invention provides a kind of negative roller skin pass rolling method that is suitable for soft steel, based on six roller UCM milling trains, comprise following concrete steps:

A. pump the former backing roll of UCM planishing mill, using former intermediate calender rolls as new backing roll, thereby form the four roller planishing mills that backing roll can play;

B. backing roll is set to negative roller;

The initial set value F of the objective control function that C. given plate shape, roll gap pressure and the draught pressure cross direction profiles uniformity form ₀, work roll bending sets step delta S, backing roll shifting amount is set step delta δ;

D. define backing roll shifting amount and set pilot process parameter k ₁, make the setting value δ=k of backing roll shifting amount ₁g Δ δ;

E. define work roll bending power and set pilot process parameter k ₂, make the setting value of work roll bending power $S_w=-S_{w\max }^{-}+k_2\mathrm{g\ΔS};$

F. calculating this four rollers planishing mill is H in the thickness cross direction profiles value of band supplied materials _j, supplied materials average thickness is that the cross direction profiles value of H, incoming profile is L _j, band width be that B, percentage elongation are ε ₀, average forward pull is T ₁, average backward pull is T ₀, work roll bending is S _w, backing roll shifting amount is the planisher exit plate shape Distribution Value σ under δ _1i, roll gap pressure cross direction profiles value q _wmiand draught pressure cross direction profiles value q _i;

G. build the objective control function being formed by plate shape, roll gap pressure and the draught pressure cross direction profiles uniformity, and calculate its value F;

H. by F and F ₀compare, obtain work roll bending power actual setpoint S _wywith backing roll shifting amount actual setpoint δ _y, supply milling train to carry out the roll control of soft steel.

Described step H specifically comprises the following steps:

H1. judge inequality F < F ₀whether set up: if inequality is set up, make S _wy=S _w, δ _y=δ, F ₀=F proceeds to step H2; If inequality is false, directly proceed to step H2;

H2. judge inequality whether set up: if inequality is set up, make k ₂=k ₂+ 1, proceed to step e; If inequality is false, proceed to step H3;

H3. judge inequality δ < δ _maxwhether set up: if inequality is set up, make k ₁=k ₁+ 1, proceed to step D; If inequality is false, proceed to step H4;

H4. finally obtain work roll bending power actual setpoint S _wywith backing roll shifting amount actual setpoint δ _y, export and supply milling train to carry out the roll control of soft steel.

In described step B, backing roll is set to negative roller, and its setting value is P/2,

$P=\frac{({\mathrm{\&sigma;}}_s-\frac{T_0+T_1}{2})\mathrm{gHg}(1-{\mathrm{\&epsiv;}}_0)}{\mathrm{\&mu;}}\left\{\exp \right\{\frac{\mathrm{\&mu;g}\left\{\frac{1}{2}(a_1\ln \left({\mathrm{\&epsiv;}}_0\right)+a_0)\right[\frac{D_w{\mathrm{\&epsiv;}}_0\mathrm{\&mu;}}{2}+\sqrt{{\left(\frac{D_w{\mathrm{\&epsiv;}}_0\mathrm{\&mu;}}{2}\right)}^2+{2D}_{w}H{\mathrm{\&epsiv;}}_0}\left]\right\}}{H(1-{\mathrm{\&epsiv;}}_0)}\}-1\}B$

In formula, P is band total draught pressure when rolling on former UCM planishing mill; B is strip width; a ₀, α ₁being respectively smooth steel grade and operating mode influence coefficient, is constant; D _wfor work roll diameter; ε ₀for band percentage elongation; μ is coefficient of friction; H is average thickness; σ _sfor band yield strength; T ₁, T ₀for the average front and back of band tension force.

In step G, the computing formula of described objective control function F is as follows:

$F={\mathrm{\&alpha;}}_1\frac{\max \left\{{\mathrm{\&sigma;}}_{1i}\right\}-\min \left\{{\mathrm{\&sigma;}}_{1i}\right\}}{T_1}+{\mathrm{\&alpha;}}_2\frac{\max \left\{q_{\mathrm{mwi}}\right\}-\min \left\{q_{\mathrm{mwi}}\right\}}{\frac{1}{N}\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}{q}_{\mathrm{mwi}}}+{\mathrm{\&alpha;}}_3\frac{\max \left\{q_i\right\}-\min \left\{q_i\right\}}{\frac{1}{M}\underset{i=1}{\overset{M}{\mathrm{\&Sigma;}}}{q}_i},$ α in formula ₁, α ₂, α ₃for weight coefficient, and α ₁+ α ₂+ α ₃=1.0.

In step C, it is 0.5t that described work roll bending is set step delta S value, and it is 1mm that HCB backing roll shifting amount is set step delta δ value.

In sum, the negative roller skin pass rolling method that is suitable for soft steel of the present invention is by pumping the former backing roll of UCM planishing mill, form the four roller planishing mills that backing roll can play, make milling train spring curve in the time of little draught pressure still remain on linear zone, control matches with work roll bending by backing roll play simultaneously, in realizing stable accurate control of plate shape, improve the uniformity coefficient of draught pressure and roll gap pressure cross direction profiles, improve and roll rear strip surface quality, improve roll working life, expanded its product scope.

Should be appreciated that more than the present invention generality is described and the following detailed description is all exemplary and explanat, and be intended to the further explanation that the invention provides for as claimed in claim.

Brief description of the drawings

Accompanying drawing is mainly used for providing further to be understood the present invention.Accompanying drawing shows embodiments of the invention, and with together with this description, play the effect of the principle of the invention explained.In accompanying drawing:

Fig. 1 is the milling train strain curve map of prior art.

Fig. 2 is the rolling schematic diagram of the UCM planishing mill of prior art.

Fig. 3 is the flow chart of milling method of the present invention.

Fig. 4 is for pumping the rolling schematic diagram of the four roller planishing mills that form after backing roll.

Band exit plate shape scatter chart when Fig. 5 a, Fig. 5 b are respectively two kinds of ideal format products employing HCB pattern rollings;

Fig. 6 a, Fig. 6 b are respectively two kinds of ideal format products band exit plate shape scatter chart while adopting existing UCM pattern rolling;

Roll-force cross direction profiles curve map when Fig. 7 a, Fig. 7 b are respectively two kinds of ideal format products employing HCB pattern rollings;

Fig. 8 a, Fig. 8 b are respectively two kinds of ideal format products roll-force cross direction profiles curve map while adopting existing UCM pattern rolling;

Detailed description of the invention

Describe technical scheme of the present invention in detail below in conjunction with accompanying drawing.Wherein, identical label is for representing identical element, and concrete technical term in following description does not form the substantial limit to technical scheme of the present invention itself.In fact, the known various variations of those skilled in the art all allow.

Taking specification as 0.20*1000mm, yield strength is as the soft steel of 100Mpa is example, and in conjunction with shown in Fig. 3, adopts the negative roller smoothing and rolling process of soft steel that carries out of the present invention as follows:

First, primary data is prepared: collect the main equipment parameters of the smooth unit of former UCM, mainly comprise the radius R of working roll _w=180mm, intermediate calender rolls radius R _m=240mm, working roll bending cylinder centre-to-centre spacing l _w=2400mm, intermediate calender rolls roll-bending cylinder centre-to-centre spacing l _m=2400mm, the long L of the working roll body of roll _w=1220mm, the long L of the intermediate calender rolls body of roll _m=1220mm, working roll adopt plain-barreled roll, its Die parameter Δ D _wi=0, intermediate calender rolls also adopts plain-barreled roll, its Die parameter Δ D _mi=0, the maximum positive and negative bending roller force of working roll (absolute value) that unit allows the maximum negative bending roller force (absolute value) of intermediate calender rolls that unit allows the maximum shifting amount δ of intermediate calender rolls that unit allows _max=200mm; The given band Cross slat number M=29 of unit, the number N=37 of roll Cross slat unit; The smooth crucial rolling technological parameter with steel is treated in collection, mainly comprises: the thickness cross direction profiles value H of band supplied materials _j(its numerical value is as shown in table 1), the cross direction profiles value L of supplied materials average thickness H=0.2mm, incoming profile _j=0, the width B=1000mm of band, percentage elongation ε ₀=0.45%, average forward pull T ₁=20Mpa, average backward pull T ₀=25Mpa;

Table 1 is the thickness cross direction profiles value of band supplied materials

Bar unit	H j	Bar unit	H j	Bar unit	H j
						1	0.19306	11	0.20263	21	0.20193
2	0.19481	12	0.20279	22	0.20149
						3	0.19631	13	0.20288	23	0.20093
4	0.1976	14	0.20297	24	0.20032
						5	0.19869	15	0.20302	25	0.19867
6	0.20027	16	0.20295	26	0.19759
						7	0.20097	17	0.2029	27	0.19627
8	0.20148	18	0.2028	28	0.19478
						9	0.20185	19	0.20262	29	0.19306
10	0.20218	20	0.20218	?	?

Secondly, pass through rolling force models

$P=\frac{({\mathrm{\&sigma;}}_s-\frac{T_0+T_1}{2})\mathrm{gHg}(1-{\mathrm{\&epsiv;}}_0)}{\mathrm{\&mu;}}\left\{\exp \right\{\frac{\mathrm{\&mu;g}\left\{\frac{1}{2}(a_1\ln \left({\mathrm{\&epsiv;}}_0\right)+a_0)\right[\frac{D_w{\mathrm{\&epsiv;}}_0\mathrm{\&mu;}}{2}+\sqrt{{\left(\frac{D_w{\mathrm{\&epsiv;}}_0\mathrm{\&mu;}}{2}\right)}^2+{2D}_{w}H{\mathrm{\&epsiv;}}_0}\left]\right\}}{H(1-{\mathrm{\&epsiv;}}_0)}\}-1\}B$

Calculating average thickness is that H=0.2mm, width are that B=1000mm, percentage elongation are ε ₀=0.45% band is R at working roll radius _wdraught pressure P=56t on the UCM planishing mill of=180mm when rolling;

Then carry out smooth mode decision: judge inequality do (56/2≤40) set up? obviously inequality is set up, and illustrates and now needs to adopt four rollers of the present invention to bear roller rolling,

A. pump the backing roll 1 (seeing Fig. 2) of the smooth unit of former UCM, using former intermediate calender rolls 2 as new backing roll, (be designated hereinafter simply as HCB planishing mill, as shown in Figure 4) thereby form the four roller planishing mills that backing roll can play; Shown in Fig. 2, Fig. 43 is working roll.

B. backing roll roller new HCB planishing mill is set as to negative bending roller force, its value is set as P/2=28t;

C. the initial set value of given plate shape, roll gap pressure and draught pressure cross direction profiles uniformity objective control function, as set initial set value F ₀=1.0 × 10 ¹⁰, work roll bending is set step delta S=0.5t, HCB backing roll shifting amount is set step delta δ=1mm;

D. define HCB backing roll shifting amount and set pilot process parameter k ₁, and make k ₁=0, make the setting value δ=k of HCB backing roll shifting amount ₁g Δ δ=0;

E. define work roll bending and set pilot process parameter k ₂, and make k ₂=0, make the setting value of work roll bending power $S_w=-S_{w\max }^{-}+k_2\mathrm{g\&Delta;S}=-30t;$

F. calculate HCB planishing mill planisher exit plate shape Distribution Value σ under current state _1i, roll gap pressure cross direction profiles value q _wmiand draught pressure cross direction profiles value q _i, as shown in table 2:

Table 2 is planisher exit plate shape Distribution Value, roll gap pressure cross direction profiles value and draught pressure cross direction profiles value

Bar unit	σ 1i	q i	q wmi	Bar unit	σ 1i	q i	q wmi
								1	14.84	50.00	37.90	20	22.04	58.20	52.42
2	15.24	50.80	38.98	21	21.04	57.40	52.24
								3	15.74	51.70	40.09	22	20.04	56.50	51.94
4	16.44	52.70	41.20	23	19.14	55.50	51.52
								5	17.24	53.60	42.37	24	18.14	54.60	50.98
6	18.14	54.60	43.57	25	17.24	53.60	50.35
								7	19.14	55.50	44.68	26	16.44	52.70	49.60
8	20.04	56.50	45.79	27	15.74	51.70	48.76
								9	21.04	57.40	46.84	28	15.24	50.80	47.86
10	22.04	58.20	47.86	29	14.84	50.00	46.84
								11	23.04	59.00	48.76	30	20.00	56.00	45.79
12	23.84	59.80	49.60	31	?	?	44.68
								13	24.64	60.40	50.35	32	?	?	43.54
14	25.34	61.00	50.98	33	?	?	42.37
								15	26.44	61.50	51.52	34	?	?	41.20
16	25.34	61.00	51.94	35	?	?	40.06
								17	24.64	60.40	52.24	36	?	?	38.95
18	23.84	59.80	52.42	37	?	?	37.90
								19	23.04	59.00	52.48	?	?	?	?

G. calculate ejecting plate shape, roll gap pressure and draught pressure cross direction profiles uniformity objective control function value F:

$F={\mathrm{\&alpha;}}_1\frac{\max \left\{{\mathrm{\&sigma;}}_{1i}\right\}-\min \left\{{\mathrm{\&sigma;}}_{1i}\right\}}{T_1}+{\mathrm{\&alpha;}}_2\frac{\max \left\{q_{\mathrm{mwi}}\right\}-\min \left\{q_{\mathrm{mwi}}\right\}}{\frac{1}{N}\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}{q}_{\mathrm{mwi}}}+{\mathrm{\&alpha;}}_3\frac{\max \left\{q_i\right\}-\min \left\{q_i\right\}}{\frac{1}{M}\underset{i=1}{\overset{M}{\mathrm{\&Sigma;}}}{q}_i}=0.387$

Wherein, α ₁=0.4, α ₂=0.3, α ₃=0.3;

H. by F and F ₀compare, obtain work roll bending power actual setpoint S _wywith backing roll shifting amount actual setpoint δ _y, supply milling train to carry out the roll control of soft steel, detailed process is as follows:

H1. judge inequality F < F ₀whether set up: if inequality is set up, make S _wy=S _w, δ _y=δ, F ₀=F proceeds to step H2; If inequality is false, directly proceed to step H2;

H2. judge inequality whether set up: if inequality is set up, make k ₂=k ₂+ 1, proceed to step e, again continue to set; If inequality is false, proceed to step H3;

H3. judge inequality δ < δ _maxwhether set up: if inequality is set up, make k ₁=k ₁+ 1, proceed to step D, again continue to set; If inequality is false, proceed to step H4;

H4. finally obtain work roll bending power actual setpoint S _wy=9.5t and backing roll shifting amount actual setpoint δ _y=75mm, exports and supplies HCB planishing mill to carry out the roll control of soft steel.

The quality in soft steel smoothing and rolling process for comparison and analysis HCB technology of the present invention and common UCM technology, utilize HCB technology of the present invention, according to the equipment and technology feature of HCB and two kinds of technology of UCM, work out simulation calculation software and analyzed.Taking the soft product made from steel of two ideal formats shown in table 3 as example, plate shape, draught pressure and the roll gap pressure cross direction profiles situation of the lower band of two kinds of patterns (HCB and UCM) when application simulation software simulates respectively identical rolling operating mode, illustrate and adopt the beneficial effect of technology of the present invention in soft steel rolling process.

The analog parameter of two kinds of typical products of table 3

(1) ideal format production board shape situation contrast

As shown in Fig. 5 a Fig. 6 b, the plate shape distribution curve of band while providing respectively ideal format product employing HCB pattern and the rolling of UCM pattern.

HCB technology obviously can find out by Fig. 5 a to Fig. 6 b, adopt the plate shape curve of HCB technology band mild, and plate shape value is little more a lot of than the plate shape value after the rolling of UCM technology, so can solve the not high enough problem of soft steel rolling strip shape quality well.

(2) ideal format product draught pressure cross direction profiles situation contrast

As shown in Fig. 7 a to Fig. 8 b, the comparison of the roll-force cross direction profiles curve while providing roll-force cross direction profiles curve and the rolling of UCM technology while adopting the rolling of HCB technology under different size.

Can find out by Fig. 7 a to Fig. 8 b, while adopting the rolling of HCB technology, the roll-force cross direction profiles curve of band is mild, peak value is little, and numerical value is little more a lot of than UCM roll-force cross direction profiles value, so HCB technology can make roll-force distribute more uniformly along band cross-sectional direction, make the deformation comparison of band even, can improve the quality of products.

Above-described embodiment is available to those of ordinary skill in the art and realizes or use of the present invention; those of ordinary skill in the art can be without departing from the present invention in the case of the inventive idea; above-described embodiment is made to various modifications or variation; thereby protection scope of the present invention do not limit by above-described embodiment, and it should be the maximum magnitude that meets the inventive features that claims mention.

Claims (5)

1. a negative roller skin pass rolling method that is suitable for soft steel, based on six roller UCM milling trains, is characterized in that,

Comprise following concrete steps:

A. pump the former backing roll of UCM planishing mill, using former intermediate calender rolls as new backing roll, thereby form the four roller planishing mills that backing roll can play;

B. backing roll is set to negative roller;

The initial set value F of the objective control function that C. given plate shape, roll gap pressure and the draught pressure cross direction profiles uniformity form ₀, work roll bending sets step delta S, backing roll shifting amount is set step delta δ;

D. define backing roll shifting amount and set pilot process parameter k ₁, make the setting value δ=k of backing roll shifting amount ₁Δ δ;

E. define work roll bending power and set pilot process parameter k ₂, make the setting value of work roll bending power for the intermediate calender rolls maximum that unit allows is born bending roller force;

F. calculating this four rollers planishing mill is H in the thickness cross direction profiles value of band supplied materials _j, supplied materials average thickness is that the cross direction profiles value of H, incoming profile is L _j, band width be that B, percentage elongation are ε ₀, average forward pull is T ₁, average backward pull is T ₀, work roll bending is S _w, backing roll shifting amount is the planishing mill exit plate shape Distribution Value σ under δ _1i, roll gap pressure cross direction profiles value q _wmiand draught pressure cross direction profiles value q _i;

G. build the objective control function being formed by plate shape, roll gap pressure and the draught pressure cross direction profiles uniformity, and calculate its value F;

H. by F and F ₀compare, obtain work roll bending power actual setpoint S _wywith backing roll shifting amount actual setpoint δ _y, supply milling train to carry out the roll control of soft steel.

2. the negative roller skin pass rolling method that is suitable for soft steel as claimed in claim 1, is characterized in that:

Described step H specifically comprises the following steps:

H1. judge inequality F<F ₀whether set up: if inequality is set up, make S _wy=S _w, δ _y=δ, F ₀=F proceeds to step H2; If inequality is false, directly proceed to step H2;

H2. judge inequality whether set up: if inequality is set up, make k ₂=k ₂+ 1, proceed to step e; If inequality is false, proceed to step H3, the maximum positive and negative bending roller force of working roll allowing for unit;

H3. judge inequality δ < δ _maxwhether set up: if inequality is set up, make k ₁=k ₁+ 1, proceed to step D; If inequality is false, proceed to step H4;

H4. finally obtain work roll bending power actual setpoint S _wywith backing roll shifting amount actual setpoint δ _y, export and supply milling train to carry out the roll control of soft steel.

3. the negative roller skin pass rolling method that is suitable for soft steel as claimed in claim 1, is characterized in that:

In described step B, backing roll is set to negative roller, and its setting value is P/2,

In formula, P is band total draught pressure when rolling on former UCM planishing mill; B is strip width; a ₀, a ₁being respectively smooth steel grade and operating mode influence coefficient, is constant; D _wfor work roll diameter; ε ₀for band percentage elongation; μ is coefficient of friction; H is average thickness; σ _sfor band yield strength; T ₁, T ₀for the average front and back of band tension force.

4. the negative roller skin pass rolling method that is suitable for soft steel as claimed in claim 1, is characterized in that:

In step G, the computing formula of described objective control function F is as follows:

$F={\mathrm{\&alpha;}}_1\frac{\max \left\{{\mathrm{\&sigma;}}_{1i}\right\}-\min \left\{{\mathrm{\&sigma;}}_{1i}\right\}}{T_1}+{\mathrm{\&alpha;}}_2\frac{\max \left\{q_{\mathrm{mwi}}\right\}-\min \left\{q_{\mathrm{mwi}}\right\}}{\frac{1}{N}\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}{q}_{\mathrm{mwi}}}+{\mathrm{\&alpha;}}_3\frac{\max \left\{q_i\right\}-\min \left\{q_i\right\}}{\frac{1}{M}\underset{i=1}{\overset{M}{\mathrm{\&Sigma;}}}{q}_i},$ α in formula ₁, α ₂, α ₃for weight coefficient, and α ₁+ α ₂+ α ₃=1.0.

5. the negative roller skin pass rolling method that is suitable for soft steel as claimed in claim 1, is characterized in that:

In step C, it is 0.5t that described work roll bending is set step delta S value, and it is 1mm that backing roll shifting amount is set step delta δ value.