CN101274335A - Control method of stretch-reducing mill steel tube thickening terminal - Google Patents

Abstract

The invention relates to a chipping control technique of head and rear thickened ends of a steel tube which is used in a stretch reducing process of a seamless steel tube. A control method of the thickened ends of the steel tube of a stretch reducing machine computes a control factor table of the thickened ends of the steel tube according to the thickness distribution rule of tube end walls of the stretch reducing machine, and by utilizing the factor table, the control method can adaptively increase and decrease the number of machine frames that participate in the CEC action according to the length change of the thickened ends in the rolling process, and realize the shortening of the head and rear thickened ends by coordinating with the adjustment of additive tension that acts on the head and rear thickened ends of the steel tube; the computation of the CEC factor table of the stretch reducing machine comprises the following steps: a basic speed governing level and a largest speed governing level are determined according to average tension; original CEC speed governing factors are computed according to the working diameter change of a roller; an original CEC speed governing factor table is constructed; the number of the machine frames that simultaneously participate in the CEC action in each machine frame position is determined according to the extensibility of the steel tube; the original CEC factor table is revised by combining with the number of the machine frames that simultaneously participate in the CEC action in each machine frame position. The chipping control technique of the head and rear thickened ends of the steel tube can effectively shorten the length of the thickened ends of the steel tube and improve the steel tube yield.

Description

Control method of stretch-reducing mill steel tube thickening terminal

Technical field

The steel pipe that the present invention relates to tension diameter-reducing procedure of seamless steel tube thickens end-grain cutting end to end and decreases control (Crop End Control is called for short CEC) technology.

Background technology

Steel pipe is realized by adjusting steel pipe tension force between each frame in the wall thickness change of stretch-reducing mill, and the tension force between each frame is produced by the speed difference between each roll.Pipe end thickens the characteristic phenomenon that phenomenon is a stretch reducing.Pipe end thicken be commonly considered as since in the operation of rolling steel pipe hold end to end by be in that tension force rises and tension force decline frame between the time, the little generation of stable rolling state between the constant frame of warp tension ratio tension force of being born.Therefore, the thinking of steel pipe thickened end control (hereinafter to be referred as CEC) control is the compensation that part of effect that pipe end lacked, and increases speed difference between adjacent frame when pipe end has just been nipped frame, produce transient state than hightension, reached the purpose that shortens thickened end.

The control of existing C EC head end is mainly controlled by front end delay-level, the front end prompt drop factor and whole several three parameters of frame that participate in of adjusting degree controller PLC able to programme.And the control of CEC tail end is mainly controlled by tail end interference order, the tail end prompt drop factor and whole several three parameters of frame that participate in.The speed that participation CEC prompt drop changes in the prior art is dynamically adjusted and is fixed in the operation of rolling after in a single day the frame number is set by the operative employee, by front end delay-level and two parameters decisions of tail end interference order.

Steel pipe thickened end end to end is actually in the operation of rolling along with steel pipe preceding and then ever-increasing in milling train, only adopt fixing several frames that thickened end is carried out the consequence that CEC effect produces to be: act on frame on the one hand and too much can affact the steel pipe normal end to CEC, act on the very few effect that can not reach the shortening thickened end of frame on the other hand.

Summary of the invention

The object of the present invention is to provide a kind of control method of stretch-reducing mill steel tube thickening terminal, this control method can be adjusted steel pipe thickened end control action frame number according to the variation of thickened end in the operation of rolling, can effectively shorten steel pipe thickened end length, reduce thickening the end-grain cutting damage, improve the steel pipe lumber recovery.

The present invention is achieved in that a kind of control method of stretch-reducing mill steel tube thickening terminal,

Be to subtract machine pipe end Thickness Distribution rule calculating steel pipe thickened end controlling elements table according to opening, utilize this factor table can be according to thickened end length in the variation of the operation of rolling and adaptive increase and decrease participates in the frame number of CEC effect, mating reaction steel pipe end to end the adjustment realization of the additional tension of thickened end further shorten thickened end end to end;

The step of calculating stretch-reducing mill steel tube thickening terminal controlling elements table is:

1) determines basic speed governing grade and maximum speed governing grade according to mean tension;

Speed governing grade in basis is that the steel pipe head has just entered frame and the steel pipe afterbody will enter the frame number of the initial participation steel pipe thickened end control speed governing of frame;

Speed governing grade in basis is opened by steel pipe and is subtracted rolling mean tension decision, and mean axis is to coefficient of tension x _1mComputing formula as follows:

Wherein, establish d _MK, d _MRBe respectively the mean outside diameter of hollow forging and production tube, S _k, S _RBe respectively the wall thickness of hollow forging and production tube, then

Be tangential deformation,

Be radial deformation, ${\mathrm{\ϵ}}_m=\frac{1}{2}(\frac{S_K}{d_{\mathrm{mK}}}+\frac{S_R}{d_{\mathrm{mR}}})$ For mean wall directly than;

To the coefficient of tension, determine basic speed governing grade according to the mean axis that calculates again;

Maximum speed governing grade is meant the maximum frame numbers that participate in steel pipe thickened end control speed governing simultaneously, and maximum speed governing grade is restricted to 7 frames, and the frame number that promptly participates in speed governing arbitrarily shelf position the time mostly is 7 most;

2) according to the original steel pipe thickened end control of the roll working diameter change calculations speed governing factor;

The computing formula of working diameter is:

D _k＝D-C _kd _k (2)

In the formula: desirable roller diameter is D, and the roll Pass diameter of k frame is d _k, the scale parameter of working diameter is C _k

When steel pipe was in normal rolling position, the scale parameter of the roll working diameter of k frame was C _k, when rolling end to end, the scale parameter of the roll working diameter of k frame is C _k ⁽ⁱ⁾, i represents the variation progression of roll working diameter herein;

Suppose that the normal rolling rotating speed of k frame is ω _k, steel pipeline speed is v _k, if after adopting the control of steel pipe thickened end to adjust rotating speed, rotating speed is ω _k, steel pipeline speed is v _k, then

v _k＝ω _kπ(D-C _kd _k) (3)

${\stackrel{\‾}{v}}_k={\stackrel{\‾}{\mathrm{\ω}}}_k\mathrm{\π}(D-C_k^{\left(i\right)}{d}_k)---\left(4\right)$

Constant for the linear velocity that guarantees steel pipe, should satisfy v _k=v _k, promptly

${\mathrm{\ω}}_k(D-C_k{d}_k)={\stackrel{\‾}{\mathrm{\ω}}}_k(D-C_k^{\left(i\right)}{d}_k)$

So have

${\stackrel{\‾}{\mathrm{\ω}}}_k=\frac{(D-C_k{d}_k)}{(D-C_k^{\left(i\right)}{d}_k)}{\mathrm{\ω}}_k---\left(5\right)$

Therefore, steel pipe thickened end control speed governing is

${\mathrm{\Δ\ω}}_k^{\left(i\right)}={\stackrel{\‾}{\mathrm{\ω}}}_k-{\mathrm{\ω}}_k=\frac{\left(C_k^{\left(i\right)}-C_k\right)d_k}{(D-C_k^{\left(i\right)}{d}_k)}{\mathrm{\ω}}_k---\left(6\right)$

The steel pipe thickened end control speed governing factor is

${\mathrm{\Δn}}_k^{\left(i\right)}=\frac{(C_k^{\left(i\right)}-C_k)d_k}{(D-C_k^{\left(i\right)}{d}_k)}---\left(7\right)$

For head end:

The normal parameter of the working diameter of every breast roller is C _KH, head end speed governing factor computing formula is:

${\mathrm{\Δn}}_{\mathrm{kh}}^{\left(i\right)}=\frac{((1-\frac{i-1}{2(p-1)})-C_{\mathrm{kH}})d_k}{(D-(1-\frac{i-1}{2(p-1)})d_k)}---\left(8\right)$

In the formula: p is the progression of steel pipe thickened end control and regulation;

I is 1 ..., p;

For tail end:

The normal parameter of the working diameter of every breast roller is C _KT, then tail end speed governing factor computing formula is:

${\mathrm{\Δn}}_{\mathrm{kt}}^{\left(i\right)}=\frac{(\cos \left(\frac{i-1}{3(p-1)}\mathrm{\π}\right)-C_{\mathrm{kT}})d_k}{(D-\cos \left(\frac{i-1}{3(p-1)}\mathrm{\π}\right)d_k)}---\left(9\right)$

3) the original steel pipe thickened end control of structure speed governing factor table

Multistage speed by every frame is regulated, and can obtain original head end and tail end steel pipe thickened end control speed governing factor table according to formula (8) and (9);

4) determine every frame place to participate in the frame number of steel pipe thickened end control action simultaneously according to the steel pipe percentage elongation;

If the percentage elongation of each frame is: λ ₁, i=1,2 ..., m, herein, when percentage elongation is interpreted as steel pipe from the 1st frame to the i frame, the extension ratio of steel pipe, then the computing formula of percentage elongation is:

${\mathrm{\λ}}_L\left(k\right)=\frac{{\mathrm{\ω}}_k(D-C_k{d}_k)}{{\mathrm{\ω}}_1(D-C_1{d}_1)}---\left(13\right)$

$m_k=\frac{L_{\mathrm{Ve}}*{\mathrm{\λ}}_L\left(k\right)}{{\text{\λ}}_L\left(n\right)*C_d}---\left(14\right)$

m _k-Di k frame place participates in the frame number of CEC effect simultaneously

L _Ve-thickened end length

λ _L(k)-the extension ratio of k frame

N-participates in institute's organic frame number of CEC control, 1,2...n

C _d-average frame spacing

5) participate in the frame number of steel pipe thickened end control action simultaneously in conjunction with every frame place, revise original steel pipe thickened end controlling elements table;

Integrating step 4) the every frame place that draws participates in the frame number of CEC effect simultaneously, according to " speed series changes rolling wall thickness invariance principle on year-on-year basis " the original CEC factor is pressed on year-on-year basis and revises, and draws brand-new CEC factor table;

This factor table has considered that every frame place should participate in the calculating of the frame number of CEC effect simultaneously, can increase the frame number that participates in the CEC effect simultaneously according to the extension of steel pipe in frame.

The present invention subtracts machine pipe end Thickness Distribution rule and designs brand-new CEC factor table according to opening, utilize this factor table can be according to thickened end length in the variation of the operation of rolling and adaptive increase and decrease participates in the frame number of CEC effect, mating reaction steel pipe end to end the adjustment realization of the additional tension of thickened end further shorten the purpose of thickened end end to end.

The present invention compared with prior art, two parameters of front end delay-level and tail end interference order have been cancelled, what propose can change the technology that the original additional tension of technical scheme of additional tension effect frame number only acts on fixing several frames according to the CEC factor table greater advantage is arranged, can effectively shorten steel pipe thickened end length, reduce thickening the end-grain cutting damage, improve the steel pipe lumber recovery.

Description of drawings

Fig. 1 changes schematic diagram for the roll radius of clean-up;

Fig. 2 is CEC factor table mechanism figure;

Fig. 3 is the comparison schematic diagram that ideal format 152.5 * 5.75-73.03 * 5.6 head end thickened end adopt CEC factor front and back;

Fig. 4 is ideal format 152.5 * 5.75-73.03 * 5.6C end sample (every section 100MM) schematic diagram;

Fig. 5 is the comparison schematic diagram that ideal format 152.5 * 5.75-73.03 * 5.6 tail end thickened end adopt CEC factor front and back;

Fig. 6 is ideal format 152.5 * 5.75-73.03 * 5.6A end sample (every section 100MM) schematic diagram.

The specific embodiment

The invention will be further described below in conjunction with the drawings and specific embodiments.

Referring to Fig. 2, control method of stretch-reducing mill steel tube thickening terminal is the lane database that is kept at process control station (L2 layer) at the different CEC factor tables of different rolling specs, and infrastructure device layer (L1 layer) is adjusted the speed of rolls by calling these CEC factor tables.The CEC factor table by each frame according to step dynamically the value of regulating the speed constitute, be the bivariate table of diaxon with frame order and sequence of steps.This form that is kept at the L2 layer with the CEC factor table more helps the technical staff at production actual optimization CEC factor table.

The main foundation that stretch-reducing mill steel tube thickening terminal CEC factor table calculates is:

1) the steel pipe situation of change of the working diameter of frame of living in end to end;

When 2) steel pipe is in different frame end to end, the extension situation of steel pipe.

Calculating novel step that subtracts the CEC factor table is:

1, determines basic speed governing grade and maximum speed governing grade according to mean tension;

2, according to the original CEC speed governing of the roll working diameter change calculations factor;

3, the original CEC speed governing factor table of structure;

4, determine every frame place to participate in the frame number of CEC effect simultaneously according to the steel pipe percentage elongation;

5, participate in the frame number of CEC effect in conjunction with every frame place simultaneously, revise original CEC factor table;

Concrete steps are:

1, basic speed governing grade of decision and maximum speed governing grade

Speed governing grade in basis is that the steel pipe head has just entered frame and the steel pipe afterbody will enter the frame number of the initial participation CEC speed governing of frame.

Maximum speed governing grade is meant the maximum frame numbers that participate in the CEC speed governing simultaneously.

Speed governing grade in basis is opened by steel pipe and is subtracted rolling mean tension decision, and mean axis is to coefficient of tension x _1mComputing formula as follows:

Wherein, establish d _MK, d _MRBe respectively the mean outside diameter of hollow forging and production tube, S _K, S _RBe respectively the wall thickness of hollow forging and production tube, then

Be tangential deformation,

Be radial deformation, ${\mathrm{\ϵ}}_m=\frac{1}{2}(\frac{S_K}{d_{\mathrm{mK}}}+\frac{S_R}{d_{\mathrm{mR}}})$ For mean wall directly than.

To the coefficient of tension, determine basic speed governing grade according to the mean axis that calculates by table 1.

The basic speed governing grade of table 1, steel pipe head end and tail end

The small-caliber thin-walled tube steel pipe extends bigger, participates in frame number (follow-up frame utilizes formula (14) to calculate the frame number that the k frame should participate in CEC simultaneously) when rule of thumb selecting 5 frames (5 * 310 millimeters) as the 1# frame; Thick-walled pipe extends point slightly in small-bore, participates in the frame number when selecting 4 frames or 3 frames as the 1# frame; Heavy caliber pipe sizing reduction is few, extends minimum, selects 2;

Maximum speed governing grade is restricted to 7 frames, and the frame number that promptly participates in speed governing arbitrarily shelf position the time mostly is 7 (under the situations of steel pipe percentage elongation maximum) most.

2, calculate the original CEC speed governing factor

The calculating of original CEC factor table mainly around steel pipe end to end the situation of change of the working diameter of frame of living in carry out.The computational methods of the working diameter of head end and tail end are different, and this mainly is to consider the situation that may have slip in the roll rotational speed adjustment process, so the speed difference that roll shop building increases should be bigger than the situation that ideal is calculated.

Adopt simple method that the parameter of the working diameter of each roll is set, can calculate steel pipe and be in any period, the working diameter of each roll.Remember that desirable roller diameter is D, the roll Pass diameter of k frame is d _k, the scale parameter of working diameter is C _k, the excursion of this parameter is 0.5 to 1.0, then the computing formula of working diameter is:

D _k＝D-C _kd _k (2)

When the note steel pipe was in normal rolling position, the scale parameter of the roll working diameter of k frame was C _k, when rolling end to end, the scale parameter of the roll working diameter of k frame is C _k ⁽ⁱ⁾, i represents the variation progression of roll working diameter herein.

The account form of the original CEC speed governing factor is as follows: suppose that the normal rolling rotating speed of k frame is ω _k, steel pipeline speed is v _k, if after adopting CEC control to adjust rotating speed, rotating speed is ω _k, steel pipeline speed is v _k, then

v _k＝ω _kπ(D-C _kd _k) (3)

${\stackrel{\‾}{v}}_k={\stackrel{\‾}{\mathrm{\ω}}}_k\mathrm{\π}(D-C_k^{\left(i\right)}{d}_k)---\left(4\right)$

Therefore, constant for the linear velocity that guarantees steel pipe, should satisfy v _k=v _k, promptly

${\mathrm{\ω}}_k(D-C_k{d}_k)={\stackrel{\‾}{\mathrm{\ω}}}_k(D-C_k^{\left(i\right)}{d}_k)$

So have

${\stackrel{\‾}{\mathrm{\ω}}}_k=\frac{(D-C_k{d}_k)}{(D-C_k^{\left(i\right)}{d}_k)}{\mathrm{\ω}}_k---\left(5\right)$

Therefore, the CEC speed governing is

${\mathrm{\Δ\ω}}_k^{\left(i\right)}={\stackrel{\‾}{\mathrm{\ω}}}_k-{\mathrm{\ω}}_k=\frac{(C_k^{\left(i\right)}-C_k)d_k}{(D-C_k^{\left(i\right)}{d}_k)}{\mathrm{\ω}}_k---\left(6\right)$

The CEC speed governing factor is

${\mathrm{\Δn}}_k^{\left(i\right)}=\frac{(C_k^{\left(i\right)}-C_k)d_k}{(D-C_k^{\left(i\right)}{d}_k)}---\left(7\right)$

For head end:

The normal parameter of the working diameter of every breast roller is C _KH, head end speed governing factor computing formula is:

${\mathrm{\Δn}}_{\mathrm{kh}}^{\left(i\right)}=\frac{((1-\frac{i-1}{2(p-1)})-C_{\mathrm{kH}})d_k}{(D-(1-\frac{i-1}{2(p-1)})d_k)}---\left(8\right)$

In the formula: p is the progression of steel pipe thickened end control and regulation;

I is 1 ..., p;

For tail end:

The normal parameter of the working diameter of every breast roller is C _KT, then tail end speed governing factor computing formula is:

${\mathrm{\Δn}}_{\mathrm{kt}}^{\left(i\right)}=\frac{(\cos \left(\frac{i-1}{3(p-1)}\mathrm{\π}\right)-C_{\mathrm{kT}})d_k}{(D-\cos \left(\frac{i-1}{3(p-1)}\mathrm{\π}\right)d_k)}---\left(9\right)$

3, the original CEC speed governing factor table of structure

Multistage speed by every frame is regulated, and can obtain original head end and tail end steel pipe thickened end control speed governing factor table according to formula (8) and (9);

4, the every frame of decision place participates in the frame number of CEC effect simultaneously

After calculating the original head end CEC speed governing factor, need be according to the situation of change of steel pipe percentage elongation, when decision steel pipe head end is in concrete frame, the pipe end length that should act on.

The formula of estimating pipe end thickened end length mainly contains following three kinds.

(1) Luo Teer (Rodder) formula:

$L_{\mathrm{VE}}=\frac{2}{R_{\mathrm{VE}}}{\mathrm{\λ}}_L{C}_d---\left(10\right)$

Perhaps be expressed from the next:

$L_{\mathrm{VE}}={2C}_d\frac{G_K}{G_R}\×\frac{S_K}{S_R}$

In the formula

R _VE---relative wall thickness reducing amount, $R_{\mathrm{VE}}=1-\frac{S_K-S_R}{S_K};$

λ _L---opening the lengthening coefficient that subtracts in the machine;

C _d---average frame spacing (mm);

G _K---hollow forging rice heavy (kg/m);

G _R---hot-rolled pipe rice heavy (kg/m);

S _K---waste thickness of pipe wall (mm);

S _R---hot-rolled pipe wall thickness (mm);

(2) Valentian (Valenta) formula:

$L_{\mathrm{VE}}=[{\mathrm{\λ}}_L\×\frac{d_K-d_R}{d_K}\×2C_d(1-\frac{S_K-S_R}{S_K})+0.15]---\left(11\right)$

In the formula

d _K---hollow forging diameter (mm);

d _R---hot-rolled pipe diameter (mm);

The meaning of all the other symbols is with the Luo Teer formula.

(3) A.A. She Fuqinke (Shevchenko) formula:

L _VE＝2λ _LC _d (12)

The meaning of this each symbol of formula is with the Luo Teer formula.

Above-mentioned each formula all is the empirical equation that draws on experimental basis.Because experimental condition and actual conditions are not quite similar, therefore, these formula have significant limitation.Show by the length of the thickened end of the hot-rolled pipe of all size is surveyed: when sizing reduction was big, actual measurement thickened end length was than the length of calculating, and when sizing reduction hour, then calculated value is higher.Especially open subtract implement the rotational speed regulation measure on the machine after, this relation just thickens unclear.The calculated value of Valentian formula and She Fuqinke formula is compared with actual value, and the former is less than normal, and the latter is bigger than normal.Top formula is all considered by carbon steel tubing.When calculating alloy pipe thickened end length, it is cut the damage value and will increase.

Therefore,, consider the hysteresis of controlling organization and the transient process in the control procedure, generally should select the calculated value length formula of thickened end end to end bigger than normal at the steel pipe type that needs carry out the control of CEC crop.

At this, still use concrete formula to coefficient of tension decision, referring to table 2 according to mean axis.

Table 2, the steel pipe section of thickening formula are end to end selected for use

Above-mentioned formula also can be adjusted according to different steel pipe models, according to the percentage elongation of steel pipe with do not adopt the length of thickened end end to end of CEC control, obtains the length formula of thickened end end to end on basis.

If the percentage elongation of each frame is: λ _i, i=1,2 ..., m. herein, when percentage elongation is interpreted as steel pipe from the 1st frame to the i frame, the extension ratio of steel pipe, then the computing formula of percentage elongation is:

${\mathrm{\λ}}_L\left(k\right)=\frac{{\mathrm{\ω}}_k(D-C_k{d}_k)}{{\mathrm{\ω}}_1(D-C_1{d}_1)}---\left(13\right)$

Determine every frame place to participate in the frame number of CEC effect simultaneously:

$m_k=\frac{L_{\mathrm{Ve}}*{\mathrm{\λ}}_L\left(k\right)}{{\text{\λ}}_L\left(n\right)*C_d}$

m _k-Di k frame place participates in the frame number of CEC effect simultaneously

L _Ve-thickened end length (14)

λ _L(k)-the extension ratio of k frame

N-participates in institute's organic frame number of CEC control, 1,2...n

C _d-average frame spacing

5, the structure of brand-new CEC factor table

Every frame place that integrating step 4 draws participates in the frame number of CEC effect simultaneously, according to " speed series changes rolling wall thickness invariance principle on year-on-year basis " the original CEC factor is pressed on year-on-year basis and revises the brand-new CEC factor table that draws.This factor table can increase the frame number that participates in the CEC effect simultaneously according to the extension of steel pipe in frame owing to considered that every frame place should participate in the calculating of the frame number of CEC effect simultaneously.

Ideal format 152.5 * 5.75-73.03 * 5.6CEC factor table is as shown in table 3.Table 3 wire frame of getting the bid out partly is preferred frame number.

Embodiment

According to the described rule of summary of the invention part,, utilize the program of independent development to calculate the novel C EC factor table of all rolling specs in conjunction with the different steel pipe specifications of product mix.Novel C EC factor table is stored in the database, rolling before the operative employee when calling pass schedule, access the CEC factor table simultaneously, and in operation interface the big or small parameter (the head end A factor and the tail end A factor) of input head rear CEC effect.

(1) ideal format of test steel pipe

The stretch reducing process of choosing ideal format 152.5 * 5.75 → 73.03 * 5.6 steel pipes carries out novel C EC control pilot production, and its specifications parameter sees Table 4.

The specifications parameter of table 4 ideal format steel pipe φ 73.03 * 5.6

The pass code name	Waste external diameter of pipe (mm)	Waste thickness of pipe wall (mm)	Production tube external diameter (mm)	Production tube wall thickness (mm)	Participate in the rolling machine frame number
						BRDBY	152.50	5.75	73.03	5.6	18

Operating parameter:

Open and subtract CEC factor table such as the subordinate list 3 that the operation of rolling is called, the rotation speed change situation of each frame when subordinate list 3 embodiment material pipe ends arrive different shelf position with the pipe tail.

Characterize two values of regulating parameter in addition of holding CEC effect size end to end:

The head end A factor → 70%, the tail end A factor → 100%.

(2) pilot production method

In actual production process, move a heat (batch) number continuously, collect the on-line measurement data and the artificial measured data of steel pipe thickened end in the production process.

Increase the rear end length data by what collect, determine optimized CEC factor table according to different factor tables and rolling parameter contrast back.

(3) mill trial results of steel pipe thickened end

Adopt new CEC engineering test found that, ideal format 73.03 * 5.6 oil pipes, A section crop reduces to 1.1M by present 1.3M, and C section back-end crop length reduces to 0.7M by present 1.35M.The A section is improved effect does not have the C section obvious, but from the effect of improving of C section, new CEC control technology tool has an enormous advantage.Referring to Fig. 3, Fig. 4, Fig. 5, Fig. 6.

The present invention can effectively shorten steel pipe thickened end length, reduces to thicken the end-grain cutting damage, improves the steel pipe lumber recovery.

Claims (3)

1. control method of stretch-reducing mill steel tube thickening terminal is characterized in that:

Subtract machine pipe end Thickness Distribution rule calculating steel pipe thickened end controlling elements table according to opening, utilize this factor table can be according to thickened end length in the variation of the operation of rolling and adaptive increase and decrease participates in the frame number of CEC effect, mating reaction steel pipe end to end the adjustment realization of the additional tension of thickened end further shorten thickened end end to end;

The step of calculating stretch-reducing mill steel tube thickening terminal controlling elements table is:

1) determines basic speed governing grade and maximum speed governing grade according to mean tension;

Speed governing grade in basis is that the steel pipe head has just entered frame and the steel pipe afterbody will enter the frame number of the initial participation steel pipe thickened end control speed governing of frame;

Speed governing grade in basis is opened by steel pipe and is subtracted rolling mean tension decision, and mean axis is to coefficient of tension x _1mComputing formula as follows:

Wherein, establish d _MK, d _MRBe respectively the mean outside diameter of hollow forging and production tube, S _K, S _RBe respectively the wall thickness of hollow forging and production tube, then

Be tangential deformation,

Be radial deformation, ${\mathrm{\ϵ}}_m=\frac{1}{2}(\frac{S_K}{d_{\mathrm{mK}}}+\frac{S_R}{d_{\mathrm{mR}}})$ For mean wall directly than;

To the coefficient of tension, determine basic speed governing grade according to the mean axis that calculates again;

Maximum speed governing grade is meant the maximum frame numbers that participate in steel pipe thickened end control speed governing simultaneously, and maximum speed governing grade is restricted to 7 frames, and the frame number that promptly participates in speed governing arbitrarily shelf position the time mostly is 7 most;

2) according to the original steel pipe thickened end control of the roll working diameter change calculations speed governing factor;

The computing formula of working diameter is:

D _k＝D-C _Kd _K (2)

In the formula: desirable roller diameter is D, and the roll Pass diameter of k frame is d _k, the scale parameter of working diameter is C _k

When steel pipe was in normal rolling position, the scale parameter of the roll working diameter of k frame was C _k, when rolling end to end, the scale parameter of the roll working diameter of k frame is C _k ⁽ⁱ⁾, i represents the variation progression of roll working diameter herein;

Suppose that the normal rolling rotating speed of k frame is ω _k, steel pipeline speed is v _k, if after adopting the control of steel pipe thickened end to adjust rotating speed, rotating speed is ω _k, steel pipeline speed is v _k, then

v _k＝ω _kπ(D-C _kd _k) (3)

${\stackrel{\‾}{v}}_k={\stackrel{\‾}{\mathrm{\ω}}}_k\mathrm{\π}(D-C_k^{\left(i\right)}{d}_k)---\left(4\right)$

Constant for the linear velocity that guarantees steel pipe, should satisfy v _k=v _k, promptly

${\mathrm{\ω}}_k(D-C_k{d}_k)={\stackrel{\‾}{\mathrm{\ω}}}_k(D-C_k^{\left(i\right)}{d}_k)$

So have

${\stackrel{\‾}{\mathrm{\ω}}}_k=\frac{(D-C_k{d}_k)}{(D-C_k^{\left(i\right)}{d}_k)}{\mathrm{\ω}}_k---\left(5\right)$

Therefore, steel pipe thickened end control speed governing is

$\mathrm{\Δ}{\mathrm{\ω}}_k^{\left(i\right)}={\stackrel{\‾}{\mathrm{\ω}}}_k-{\mathrm{\ω}}_k=\frac{(C_k^{\left(i\right)}-C_k)d_k}{(D-C_k^{\left(i\right)}{d}_k)}{\mathrm{\ω}}_k---\left(6\right)$

The steel pipe thickened end control speed governing factor is

$\mathrm{\Δ}{n}_k^{\left(i\right)}=\frac{(C_k^{\left(i\right)}-C_k)d_k}{(D-C_k^{\left(i\right)}{d}_k)}---\left(7\right)$

For head end:

The normal parameter of the working diameter of every breast roller is C _KH, head end speed governing factor computing formula is:

${\mathrm{\Δn}}_{\mathrm{kh}}^{\left(i\right)}=\frac{((1-\frac{i-1}{2(p-1)})-C_{\mathrm{kH}})d_k}{(D-(1-\frac{i-1}{2(p-1)})d_k)}---\left(8\right)$

In the formula: p is the progression of steel pipe thickened end control and regulation;

I is 1 ..., p;

For tail end:

The normal parameter of the working diameter of every breast roller is C _KT, then tail end speed governing factor computing formula is:

${\mathrm{\Δn}}_{\mathrm{kt}}^{\left(i\right)}=\frac{(\cos \left(\frac{i-1}{3(p-1)}\mathrm{\π}\right)-C_{\mathrm{kT}})d_k}{(D-\cos \left(\frac{i-1}{3(p-1)}\mathrm{\π}\right)d_k)}---\left(9\right)$

3) the original steel pipe thickened end control of structure speed governing factor table

Multistage speed by every frame is regulated, and can obtain original head end and tail end steel pipe thickened end control speed governing factor table according to formula (8) and (9);

4) determine every frame place to participate in the frame number of steel pipe thickened end control action simultaneously according to the steel pipe percentage elongation;

If the percentage elongation of each frame is: λ _i, i=1,2 ..., m, herein, when percentage elongation is interpreted as steel pipe from the 1st frame to the i frame, the extension ratio of steel pipe, then the computing formula of percentage elongation is:

${\mathrm{\λ}}_L\left(k\right)=\frac{{\mathrm{\ω}}_k(D-C_k{d}_k)}{{\mathrm{\ω}}_1(D-C_1{d}_1)}---\left(13\right)$

$m_k=\frac{L_{\mathrm{Ve}}*{\mathrm{\λ}}_L\left(k\right)}{{\mathrm{\λ}}_L\left(n\right)*C_d}$

m _k-Di k frame place participates in the frame number of CEC effect simultaneously

L _Ve-thickened end length (14)

λ _L(k)-the extension ratio of k frame

N-participates in institute's organic frame number of CEC control, 1,2...n

C _d-average frame spacing

5) participate in the frame number of steel pipe thickened end control action simultaneously in conjunction with every frame place, revise original steel pipe thickened end controlling elements table;

Integrating step 4) the every frame place that draws participates in the frame number of CEC effect simultaneously, according to " speed series changes rolling wall thickness invariance principle on year-on-year basis " the original CEC factor is pressed on year-on-year basis and revises, and draws brand-new CEC factor table;

This factor table has considered that every frame place should participate in the calculating of the frame number of CEC effect simultaneously, can increase the frame number that participates in the CEC effect simultaneously according to the extension of steel pipe in frame.

2. control method of stretch-reducing mill steel tube thickening terminal according to claim 1 is characterized in that: basic speed governing grade is extended bigger for the small-caliber thin-walled tube steel pipe, select five frames as No. 1 frame head end and tail end participate in the frame number simultaneously; Thick-walled pipe extends point slightly in small-bore, participates in the frame number when selecting four frames or three frames as No. 1 frame; Heavy caliber pipe sizing reduction is few, extends minimum, participates in the frame number when selecting two frames as No. 1 frame.

3. control method of stretch-reducing mill steel tube thickening terminal according to claim 1 is characterized in that: steel pipe thickened end length computation formula is end to end selected for use to the coefficient of tension according to mean axis,

When participating in rolling frame Lou more than or equal to 12, the mean tension coefficient is 0.0-0.3, selects the Valentian formula for use, that is:

$L_{\mathrm{VE}}=[{\mathrm{\λ}}_L\×\frac{d_K-d_R}{d_K}\×2C_d(1-\frac{S_K-S_R}{S_K})+0.15]---\left(11\right)$

In the formula

d _K---hollow forging diameter (mm);

d _R---hot-rolled pipe diameter (mm);

The meaning of all the other symbols is with the Luo Teer formula

When participating in rolling frame Lou more than or equal to 12, the mean tension coefficient is 0.3-0.65, selects the She Fuqinke formula for use, that is:

L _VE＝2λ _LC _d (12)

The meaning of this each symbol of formula is with the Luo Teer formula

When participating in rolling frame Lou more than or equal to 12, the mean tension coefficient is 0.65-0.75, selects the Luo Teer formula for use, that is:

$L_{\mathrm{VE}}=\frac{2}{R_{\mathrm{VE}}}{\mathrm{\λ}}_L{C}_d---\left(10\right)$

Perhaps be expressed from the next:

$L_{\mathrm{VE}}=2C_d\frac{G_K}{G_R}\×\frac{S_K}{S_R}$

In the formula

R _VE---relative wall thickness reducing amount, $R_{\mathrm{VE}}=1-\frac{S_K-S_R}{S_K};$

λ _L---opening the lengthening coefficient that subtracts in the machine;

C _d---average frame spacing (mm);

G _K---hollow forging rice heavy (kg/m);

G _R---hot-rolled pipe rice heavy (kg/m);

S _K---waste thickness of pipe wall (mm);

S _R---hot-rolled pipe wall thickness (mm);

When participating in rolling frame Lou, select the Valentian formula for use, that is: less than 12

$L_{\mathrm{VE}}=[{\mathrm{\λ}}_L\×\frac{d_K-d_R}{d_K}\×2C_d(1-\frac{S_K-S_R}{S_K})+0.15].---\left(11\right)$

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