CN106055814A - Method for correcting deviation of head of strip of continuous rolling mill set - Google Patents

Abstract

This invention discloses a method for correcting the deviation of strip head in a continuous rolling mill, relating to the field of metal pressure processing technology. The method includes the following steps: collecting actual rolling force data on both sides when the finishing stand of the continuous rolling mill rolls the head of the previous strip; calculating the average value of the actual rolling forces on both sides based on the collected data; and calculating the difference in roll gap between the two sides of the finishing stand when rolling the current strip head under the condition of equal pre-set rolling forces on both sides, based on the average value, the mill rigidity of the finishing stand, and the pre-set roll gap on both sides of the finishing stand during the rolling of the previous strip, and correcting the difference in roll gap between the two sides of the finishing stand for this strip. This invention solves the problem of strip head bending and deviation during continuous rolling, which leads to inner ring misalignment in the coil.

Description

Strip Head Deviation Correction Method for Continuous Rolling Mill

technical field

The invention relates to the technical field of metal pressure processing, in particular to a strip head deviation correction method for a continuous rolling mill.

Background technique

In the production process of hot-rolled strip, when the head of the intermediate billet is threaded, due to various factors, the head of the rolled piece often deviates, resulting in misalignment of the inner ring of the coil , In severe cases, it will cause the loose layer of the inner ring, or even collapse, which not only reduces the yield, but also is not conducive to the packaging of the finished coil, and affects the appearance of the finished coil. If the trimming shears provided after the continuous rolling unit are required to trim the both sides of the rolled piece, the deviation of the head of the rolled piece will also cause the edge trimming failure. In the current production site, the operator usually corrects the deviation by adjusting the difference between the roll gaps on both sides of the stand after observing the bending deviation of the head of the rolled piece between the stands, but manual operation has hysteresis and instability.

Contents of the invention

The object of the present invention is to provide a strip head deviation correction method for a continuous rolling mill. This method can solve the problem that the inner circle of the coil is misaligned due to the bending deviation of the head of the rolled piece during the continuous rolling process.

In order to solve the problems referred to above, the technical solution adopted in the present invention is: the strip head deviation correction method of this continuous rolling mill comprises the following steps:

Step 1. Collect the actual rolling force data on both sides when the finished stand of the tandem rolling mill rolls the head of the last piece;

Step 2. Calculate the average value of the actual rolling force on both sides according to the collected data;

Step 3. According to the average value, the rolling mill stiffness of the finished product frame, and the roll gap set on both sides of the finished product frame when the last rolled piece was rolled, calculate the condition that the pre-set rolling force of the finished product frame is equal on both sides The set value of the difference between the roll gaps on both sides of the head of the rolling piece is rolled down, and the difference between the roll gaps on both sides of the finished frame of the rolling piece is corrected.

In the technical scheme of the strip head deviation correction method of the above-mentioned continuous rolling mill, the more specific technical scheme can also be: the method of step 1 collection is as follows:

Suppose the sampling length of the rolling force data at the head of the rolled piece is D, and the unit is mm, then 1500≤D≤3000. The starting point for collecting the actual rolling force data on both sides of the stand, assuming that the moving speed of the rolled piece is v, the unit is mm/s; at this time, the roll line speed of the rolling mill is V, the unit is mm/s; the forward slip value is w; the sampling time of rolling force data is t, and the unit is second; then the calculation formula of v is:

v=V(1+w)

Then the sampling time of the rolling force data is t=D/v.

Further, the calculation method of the average value of the two-sided actual rolling force in step two is as follows:

Assuming that within the sampling time t, there are N rolling force data collected on both sides, the rolling force data on the driving side are n ₁ , n ₂ , n ₃ ... n _N , and the rolling force data on the operating side are n ₁ ′,n ₂ ′,n ₃ ′...n′ _N ; then the calculation formula of the average value n _avg of the rolling force on the driving side is:

${\mathrm{<span\; class="notranslate">\; no</span>}}_{\mathrm{<span\; class="notranslate">\; a</span>}\mathrm{<span\; class="notranslate">\; v</span>}\mathrm{<span\; class="notranslate">\; g</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; no</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; no</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span><span\; class="notranslate">\; ...</span>{\mathrm{<span\; class="notranslate">\; no</span>}}_{\mathrm{<span\; class="notranslate">\; N</span>}}}{\mathrm{<span\; class="notranslate">\; N</span>}}$

The calculation formula of the average value n′ _avg of the rolling force on the operating side is:

${\mathrm{<span\; class="notranslate">\; no</span>}}_{\mathrm{<span\; class="notranslate">\; a</span>}\mathrm{<span\; class="notranslate">\; v</span>}\mathrm{<span\; class="notranslate">\; g</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; no</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; no</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; +</span><span\; class="notranslate">\; ...</span>{\mathrm{<span\; class="notranslate">\; no</span>}}_{\mathrm{<span\; class="notranslate">\; N</span>}}^{<span\; class="notranslate">\; \&prime;</span>}}{\mathrm{<span\; class="notranslate">\; N</span>}}<span\; class="notranslate">\; .</span>$

Further, the calculation method of the double-side roll gap correction amount at the head of the rolled piece in step 3 is as follows:

Assume that the transmission side set the roll gap s _last when the last piece was rolled, and the unit is mm; the operation side set the roll gap as s′ _last , the unit is mm; The roll gap is s _now , the unit is mm; the roll gap is set at the operating side as s′ _now , the unit is mm; the rolling mill stiffness of the finished product stand is M, the unit is ton/mm, and the stiffness of one side is M/2; The pre-set rolling force on the driving side and the operating side of the head of the block rolled piece should be equal, assuming that the pre-set rolling force is n _half , the unit is ton, then According to the size relationship between n _avg and n′ _avg , there are two cases to consider:

When n _avg >n′ _avg , it means that the rolling force on the drive side of the previous piece is greater than the rolling force on the operation side, the drive side of the rolled piece is thinner than the operation side, and the head of the rolled piece faces the operation side For bending, in order to reduce the pre-set rolling force on the transmission side of the piece from n _avg to n _half , according to the rolling mill bounce equation, the calculation formula of the roll gap correction Δs on the transmission side is:

$\mathrm{<span\; class="notranslate">\; \&Delta;</span>}\mathrm{<span\; class="notranslate">\; the\; s</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; no</span>}}_{\mathrm{<span\; class="notranslate">\; a</span>}\mathrm{<span\; class="notranslate">\; v</span>}\mathrm{<span\; class="notranslate">\; g</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; no</span>}}_{\mathrm{<span\; class="notranslate">\; h</span>}\mathrm{<span\; class="notranslate">\; a</span>}\mathrm{<span\; class="notranslate">\; l</span>}\mathrm{<span\; class="notranslate">\; f</span>}}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; m</span>}}$

That is, the preset value s _now of the drive side roll gap of the finished stand of the rolled piece is:

s _now =s _last +Δs

Since the deviation is corrected by correcting the roll gap difference on both sides of the rolling mill, if the preset value of the roll gap on the transmission side becomes larger, the preset value of the roll gap on the operating side will decrease accordingly, as follows:

s' _now = s' _last -Δs

When n′ _avg >n _avg , it means that the rolling force on the operation side of the previous piece of rolling is greater than that on the driving side, the operating side of the rolled piece is thinner than the driving side, and the head of the rolled piece faces the driving side Bending, in order to reduce the pre-set rolling force on the operation side of the piece from n′ _avg to n _half , according to the rolling mill bounce equation, the calculation formula of the roll gap correction Δs′ on the operation side is:

${\mathrm{<span\; class="notranslate">\; \&Delta;s</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; no</span>}}_{\mathrm{<span\; class="notranslate">\; a</span>}\mathrm{<span\; class="notranslate">\; v</span>}\mathrm{<span\; class="notranslate">\; g</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; no</span>}}_{\mathrm{<span\; class="notranslate">\; h</span>}\mathrm{<span\; class="notranslate">\; a</span>}\mathrm{<span\; class="notranslate">\; l</span>}\mathrm{<span\; class="notranslate">\; f</span>}}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; m</span>}}$

That is, the preset value s _now of the roll gap on the operation side of the finished stand of the rolled piece is:

s' _now = s' _last +Δs'

Since the deviation is corrected by correcting the roll gap difference on both sides of the rolling mill, if the preset value of the roll gap on the operating side becomes larger, the preset value of the roll gap on the transmission side will decrease accordingly, as follows:

s _now =s _last -Δs'.

The principle of the present invention is: the main reason for the deviation and bending of the head of the rolled piece in the roll gap of the rolling mill is the double-sided asymmetric rolling of the rolled piece in the roll gap of the rolling mill, and its direct performance is the double-sided rolling of the rolling mill The force difference is large. In order to prevent the head deviation of the rolled piece, this technical solution is based on the actual rolling force collected by the rolling force measuring instruments on the operation side and the transmission side of the finished product stand when the head of the last rolled piece is threaded. Data, correct the set value of the difference between the roll gaps on both sides of the finished stand of the rolled piece, and make the predicted rolling force on both sides of the rolled piece equal through correction, so as to ensure that the head of the rolled piece is in the rolling mill. Rolling is symmetrical in the roll gap, so as to prevent it from deviation at the exit of the finished product stand.

Due to the adoption of the above technical solution, the present invention has the following beneficial effects compared with the prior art: it can realize the deviation correction control of the head of the rolled piece in the continuous rolling process, and the deviation correction is timely and stable, thereby solving the problem of the inner ring misalignment of the coil.

detailed description

Below in conjunction with embodiment the present invention is described in further detail:

The strip head deviation correction method of the continuous rolling unit of the present embodiment comprises the following three steps:

Step 1. Collect the actual rolling force data on both sides when the finished stand of the tandem rolling unit rolls the head of the last rolled piece

Suppose the sampling length of the rolling force data at the head of the rolled piece is D, and the unit is mm, then 1500≤D≤3000, which is about the circumference length of the first coil, and D=2000; when the head of the rolled piece When threading the belt to the roll gap of the finished frame, the head biting signal is used as the starting point for collecting the actual rolling force data on both sides of the frame, assuming that the moving speed of the rolled piece is v, and the unit is mm/s; The roll line speed of the rolling mill is V=3000 mm/s; the forward slip value is w=0.045; the sampling time of the rolling force data is t, and the unit is second; then the calculation formula of v is:

v=V(1+w)=3000×(1+0.045)=3135 mm

The sampling time of rolling force data is

Step 2. Calculate the average value of the actual rolling force on both sides according to the collected data

Assume that within the sampling time t=0.64 seconds, the rolling force data on both sides collected by the rolling force measuring instrument are all N=5; the rolling force data on the transmission side are n ₁ =950 tons, n ₂ =960 tons , n ₃ =955 tons, n ₄ =961 tons, n ₅ =952 tons; the rolling force data on the operating side are n ₁ ′=990 tons, n ₂ ′=988 tons, n ₃ ′=985 tons, n ₄ ′ =980 tons, n ₅ ′=986 tons; then the calculation formula of the average value n _avg of the rolling force on the driving side is:

The calculation formula of the average value n′ _avg of the rolling force on the operating side is:

Step 3. According to the average value, the rolling mill stiffness of the finished product frame, and the roll gap set on both sides of the finished product frame when the last rolled piece was rolled, calculate the condition that the pre-set rolling force of the finished product frame is equal on both sides The set value of the difference between the roll gaps on both sides of the head of the rolling piece in the lower rolling process is used to correct the difference between the roll gaps on both sides of the finished frame of the rolling piece;

Due to the asymmetric rolling on both sides of the rolled piece, the deviation and bending of the head of the rolled piece is caused. Therefore, to eliminate the deviation of the rolled piece head, it should be considered to make the rolling force on both sides equal by correcting the difference between the roll gaps on both sides. , so as to ensure that the thickness of the driving side and the operating side of the rolled piece are equal. Assume that the roll gap on the drive side is set to s _last = 5.22 mm when the previous piece is rolled; the roll gap set on the operation side is s′ _last = 5.36 mm; is s _now , the unit is mm; set the roll gap on the operating side as s′ _now , the unit is mm; the rolling mill stiffness of the finished stand is M=400 tons/mm, and the stiffness of one side is M/2=200 tons/mm ; The pre-set rolling force on the driving side and the operating side of the head of the rolled piece should be equal, assuming it is n _half in tons, then

Since n′ _avg >n _avg , it means that the rolling force on the operation side of the previous piece of rolling is greater than that on the driving side, the operating side of the rolled piece is thinner than the driving side, and the head of the rolled piece is bent toward the driving side . To reduce the pre-set rolling force on the operation side of the piece from n′ _avg to n _half , according to the rolling mill bounce equation, the calculation formula of the roll gap correction Δs′ on the operation side is:

That is, the preset value s _now of the roll gap on the operation side of the finished stand of the rolled piece is:

s' _now = s' _last + Δs' = 5.36+0.0755 = 5.4355 mm

Since the deviation is corrected by correcting the roll gap difference on both sides of the rolling mill, if the preset value of the roll gap on the operating side becomes larger, the preset value of the roll gap on the transmission side will decrease accordingly, as follows:

s _now =s _last -Δs'=5.22-0.0755=5.1445 mm.

Claims (4)

1. the band head method for correcting error of a Continuous mill train, it is characterised in that comprise the following steps:

Bilateral actual roll-force data when step one, collection Continuous mill train finished frame rolling lastblock workpiece front end；

Step 2, according to the data gathered, calculate the meansigma methods of the actual roll-force of described bilateral；

Step 3, according to described meansigma methods, the mill stiffness of finished frame, lastblock rolled piece rolling time finished frame bilateral set Fixed roll stitches, and the bilateral roll gap that calculating finished frame rolls this block workpiece front end under conditions of the presetting roll-force of bilateral is equal is poor Value setting value, is modified the finished frame bilateral roll gap difference of this block rolled piece.

The band head method for correcting error of Continuous mill train the most according to claim 1, it is characterised in that: the side that step one gathers Method is as follows:

If the sampling length of workpiece front end roll-force data is D, unit is millimeter, then 1500≤D≤3000, when the head of rolled piece When threading is to the roll gap of finished frame, nip signal as rising that roll-force data actual to frame bilateral are acquired using head Initial point, it is assumed that the gait of march of rolled piece is v, unit is mm/second；Now the roll linear velocity of milling train is V, unit be millimeter/ Second；Advancing slip value is w；The sampling time of roll-force data is t, and unit is the second；Then v calculating formula is:

V=V (1+w)

The then sampling time t=D/v of roll-force data.

3. the band head method for correcting error of a Continuous mill train according to claim 1 and 2, it is characterised in that: step 2 is double The computational methods of the meansigma methods of the actual roll-force in side are as follows:

Assuming in sampling time t, the bilateral roll-force data adopted are N number of, and transmission side roll-force data are n₁,n₂, n₃...n_N, fore side roll-force data are n '₁,n′₂,n′₃...n′_N；Then meansigma methods n of transmission side roll-force_avgCalculating formula For:

$n_{avg}=\frac{n_1+n_2+...n_N}{N}$

The meansigma methods n ' of fore side roll-force_avgCalculating formula be:

$n_{avg}^{\&prime;}=\frac{n_1^{\&prime;}+n_2^{\&prime;}+...n_N^{\&prime;}}{N}.$

The band head method for correcting error of Continuous mill train the most according to claim 3, it is characterised in that: in step 3, this block rolls The computational methods of the bilateral roll gap correction of part head are as follows:

Assume that transmission side when lastblock rolled piece rolls sets roll gap as s_last, unit is millimeter；Fore side set roll gap as s′_last, unit is millimeter；The transmission side during rolling of this block rolled piece sets roll gap as s_now, unit is millimeter；Fore side sets roller Seam is s '_now, unit is millimeter；The mill stiffness of finished frame is M, and unit is ton/millimeter, then unilateral rigidity is M/2；This block The transmission side of workpiece front end and the presetting roll-force of fore side should be equal, it is assumed that presetting roll-force is n_half, unit is ton, ThenAccording to n_avgWith n '_avgBetween magnitude relationship, in two kinds of situation consider:

Work as n_avg＞ n '_avgTime, illustrate that the transmission side roll-force of lastblock rolled piece is bigger than fore side roll-force, the transmission side of rolled piece Portion is thinner than fore side edge, and workpiece front end bends to fore side, and the presetting roll-force of transmission side of this block rolled piece will be allowed from n_avg It is reduced to n_half, then according to mill spring equation, the calculating formula of roll gap correction amount s of transmission side is:

$\mathrm{\&Delta;}s=\frac{2(n_{avg}-n_{half})}{M}$

I.e. transmission side roll slot presetting definite value s of this block rolled piece finished frame_nowFor:

s_now=s_last+Δs

Rectified a deviation by the mode then passing through the roll gap difference revising milling train bilateral, if therefore transmission side roll slot presetting definite value becomes Greatly, then fore side roll slot presetting definite value can reduce accordingly, for:

s′_now=s '_last-Δs

As n '_avg＞ n_avgTime, illustrate that the fore side roll-force of lastblock rolled piece is bigger than transmission side roll-force, the operation side of rolled piece Portion is thinner than transmission side edge, and workpiece front end bends to transmission side, allow the presetting roll-force of fore side of this block rolled piece from n′_avgIt is reduced to n_half, then according to mill spring equation, the calculating formula of the roll gap correction amount s ' of fore side is:

${\mathrm{\&Delta;s}}^{\&prime;}=\frac{2(n_{avg}^{\&prime;}-n_{half})}{M}$

I.e. fore side roll slot presetting definite value s of this block rolled piece finished frame_nowFor:

s′_now=s '_last+Δs′

Rectified a deviation by the mode then passing through the roll gap difference revising milling train bilateral, if therefore fore side roll slot presetting definite value becomes Greatly, then transmission side roll slot presetting definite value can reduce accordingly, for:

s_now=s_last-Δs′。