CN103203358B - Rolling method capable of improving biting condition in rolling process of reversible rolling mill - Google Patents

Abstract

The invention discloses a rolling method capable of improving a biting condition in a rolling process of a reversible rolling mill. The rolling method comprises the following steps of (1) setting rolling reduction in a pass and a corresponding roll clearance set value according to a pre-rolling thickness of a steel plate in the rolling pass and the post-rolling thickness required by a technology, and calculating the estimated length of the steel plate after the rolling pass is completed; (2) setting the rolling reduction of the tail part of the steel plate to be 1.01-1.2 times that of the rolling reduction of the pass, rolling the steel plate according to the rolling reduction of the pass and the corresponding roll clearance set value, and when the feed length of the steel plate reaches 70-90 percent of the estimated length of the steel plate obtained in the step 1, rolling the steel plate according to the rolling reduction of the tail part of the steel plate and the corresponding roll clearance to complete the rolling pass; and (3) reversely feeding the steel plate and starting the next rolling pass. The rolling method capable of improving the biting condition in the rolling process of the reversible rolling mill has the advantages that the situation of biting slip in a rolling process can be effectively avoided, the number of passes is reduced, the productivity is improved, and the energy consumption is decreased.

Description

Improve the milling method of bite condition in the reversable mill operation of rolling

Technical field

The present invention relates to a kind of operation of rolling of reversable mill, particularly a kind of milling method improving bite condition in the reversable mill operation of rolling.

Background technology

The rough rolling step of the shaping of Medium and Heavy Plate Rolling, broadening stage and hot rolling all belongs to high part rolling, and hot rolling roughing mill and heavy and medium plate mill all adopt reversable mill usually.In the operation of rolling, usually wish by as far as possible few passage, reach the target thickness of rolling sequence as early as possible.The advantage reducing rolling time mainly contains 2 points, and one is improve the Rolling Production rate of producing line; Two are the reduction of the temperature loss in the operation of rolling, thus can reduce heating furnace tapping temperature, economize energy.Reduce passage and just need the drafts increasing every time, but increase pressure quantitative limitation is mainly bite condition.Rely on the frictional force between pivotal roll and rolled piece, by rolled piece, the phenomenon pulled between roll is called and nips roll.Enter between roll for making rolled piece and realize plastic deformation, roll must have the horizontal applied force identical with roll-force direction to rolled piece.Under the condition not having additional external force effect, nipping for realizing nature, must be that bite force is greater than and nips resistance just likely, otherwise skidding of will nipping.

At " Metal Forming: rolling therory and technique " (Wang Tingpu etc., Beijing: metallurgical industry publishing house, 2001.8) mention in the second section " realizing the condition of the operation of rolling " (P13-P18) of first section " rolling therory ": after rolled piece is nipped by roll, start filling roll gap gradually, in the process of rolled piece filling roll gap, angle between product front end and roll axle center on line constantly reduces, when rolled piece fills full roll gap completely, namely start the stable rolling stage.Larger than the maximum nip angle started when nipping in the maximum permission nip angle in stable rolling stage, correspondingly, the drafts that both allow is also different, the drafts several times larger than maximum permission drafts when nipping of the maximum permission in stable rolling stage.Therefore, according to bite condition, just can draw: all factors of every all factors and reduction nip angle that can improve coefficient of friction are all conducive to nipping.

Usually adopt following methods to improve bite condition in prior art, avoid skidding of nipping:

(1) roller diameter is increased;

(2) by external force, rolled piece is forced to push in roll;

(3) roll or rolled piece surface state is changed, to improve angle of friction.

But adopt above method to there is following problem:

(1) increase roller diameter, mill housing size, power of motor etc. certainly will be increased, significantly can increase milling train equipment investment;

(2) forced to push in roll by rolled piece by external force, need increase additional thrust equipment, current technology is reliably immature;

(3) change roll or rolled piece surface state, the surface quality of steel plate can be caused to decline, easily cause to wipe scratching.

Summary of the invention

For solving the problem, the invention provides a kind of milling method improving bite condition in the reversable mill operation of rolling, to avoid nipping the generation of skidding, the drafts of other passages beyond first passage can be improved, reach and boost productivity and energy-saving and cost-reducing object.

For achieving the above object, the milling method improving bite condition in the reversable mill operation of rolling of the present invention, comprises the following steps:

Step one, the ingoing ga(u)ge of this passage be rolled according to steel plate and the outgoing gauge of technological requirement set the fixed value of roller slit of this reduction in pass and correspondence thereof, and calculate steel plate adopt the fixed value of roller slit of described reduction in pass and correspondence thereof carry out this passes complete after steel plate estimated length;

Step 2, setting steel plate tail drafts is described reduction in pass 1.01 ~ 1.2 times, according to the fixed value of roller slit of described reduction in pass and correspondence thereof, steel plate is rolled, when steel plate enter steel length reach 70% ~ 95% of the steel plate estimated length described in step one time, by the roll gap of described steel plate tail drafts and correspondence thereof, steel plate is rolled, completes the rolling of this passage;

Step 3, steel plate reverse enter steel, start the rolling of lower a time.

The milling method improving bite condition in the reversable mill operation of rolling of the present invention, in the operation of rolling of a passage, when steel plate rolling is to during close to throwing steel, increase drafts, reduce mill roll-gap position, make afterbody thickness partially thin, instantly a time reverse enter steel when starting rolling, the actual drafts then stinging steel plate during steel reduces, thus avoids because drafts is excessive, the difficulty of nipping caused.The milling method improving in the reversable mill operation of rolling lower a time bite condition of the present invention, effectively can avoid skiddings of nipping in the operation of rolling, and then reduce road number of times, saving rolling time, thus improves productivity ratio, reduces energy consumption.

Accompanying drawing explanation

Fig. 1 is the flow chart that the present invention improves the milling method of bite condition in the reversable mill operation of rolling;

Fig. 2 is the schematic diagram adopting the present invention to carry out first passes;

Fig. 3 is the schematic diagram adopting the present invention to carry out pony-roughing pass rolling;

Fig. 4 is the schematic diagram adopting the present invention to carry out last passes.

Detailed description of the invention

See 1 being steel plate in Fig. 1 ~ Fig. 4, figure, 2 is roll, and the milling method adopting the present invention to improve bite condition in the reversable mill operation of rolling is rolled steel plate 1.Comprise the following steps:

The setting (S1) of step one, reduction in pass and roll gap

When reversable mill carries out the rolling of a passage to steel plate, carry out the outgoing gauge setting reduction in pass dh of the ingoing ga(u)ge of this passes and technological requirement and the fixed value of roller slit gap of correspondence thereof according to steel plate, and calculate steel plate adopt the fixed value of roller slit gap of described reduction in pass dh and correspondence thereof carry out this passes complete after steel plate estimated length length.Reduction in pass dh is the difference of the ingoing ga(u)ge of steel plate and the outgoing gauge of technological requirement.Existing milling train is all configured with milling train pass schedule computation model usually, the fixed value of roller slit gap of reduction in pass dh, its correspondence can be provided by this model, and this passes complete after steel plate length length.

Step 2, steel plate rolling (S2)

Setting steel plate enters afterbody drafts dh after steel ₁for 1.01 ~ 1.2 times of this reduction in pass dh, and calculate described afterbody drafts dh ₁corresponding roll gap gap ₁:

gap ₁＝gap+(dh ₁-dh)

Wherein, dh ₁: afterbody drafts, unit: mm; gap ₁: afterbody drafts dh ₁corresponding roll gap, unit: mm; Dh: reduction in pass, unit: mm; .

According to the fixed value of roller slit gap of described reduction in pass dh and correspondence thereof, steel plate is rolled, when steel plate enter steel length reach 70% ~ 95% of the steel plate estimated length length described in step one time, by described afterbody drafts dh ₁and the roll gap gap of correspondence ₁steel plate tail is rolled, as shown in Figure 2.

Step 3, steel plate reverse enter steel, start the rolling (S3) of lower a time

After the rolling of completing steps two, steel plate reverse enter steel, start the rolling of lower a time, as shown in Figure 3.Described reverse enter steel refer to that steel enters in the opposite direction in the steel side of entering be rolled with step 2 light plate.Steel plate tail now in step 2 becomes steel plate head in this passage, and the steel plate head of this passage is thinning due to the dynamic pressure tail of upper a time, and then steel plate normally enters steel, repeats above-mentioned steps one and step 2, until that passage that extreme trace is secondary.Extreme trace adopts pair rolling method to be rolled, as shown in Figure 4.

Adopt milling method of the present invention, preferably adopt the reversable mill possessing holding-down device of hydraulic and positions of materials tracking system.

Holding-down device of hydraulic be with hydraulic cylinder replace traditional housing screw, nut adjusts roller gap.In this device, except hydraulic cylinder and servo valve supporting with it and hydraulic system, also comprise instrumentation and computing control system.The maximum feature of holding-down device of hydraulic is that fast-response is good, and Adjustment precision is high.

Positions of materials tracking system carries out the detection of steel plate position by arranging the software approach such as the high accuracy such as hot metal detector (HMD), grating (LD), laser velocimeter (SD), highly sensitive detection means and Load Torque Observer (LR).The detection that steel plate enters steel length completes by positions of materials tracking system.

Above-mentioned holding-down device of hydraulic and positions of materials tracking system are existing in more advanced heavy and medium plate mill and hot rolling roughing reversable mill at present to be adopted, and therefore no longer describes in detail here.

Why this milling method can overcomes in the operation of rolling lower a time is nipped skidding, its general principle is the difference of the maximum permission nip angle of stinging in steel and stable rolling process, suitable lower a time is selected to sting the laggard steel length of steel, the mill length that when namely determining to reach stable rolling state, steel plate is corresponding.

Because in the operation of rolling, the steel plate tail of this passage is the steel plate head of lower a time, it is as being free end during steel plate head, steel plate rolling outlet for freely extend without restrained condition, rolling deformation is still very unstable, what the present invention adopted enters steel length is increase drafts behind 70 ~ 95% of steel plate estimated length after this passes completes, make steel plate tail thinning, when described steel plate tail is when lower a time is as steel plate head, the length of its thinned section can make it carry out ensureing when stinging steel enough stinging the laggard steel length of steel, rolling deformation can keep stable state.

Determine length that afterbody pressure starts to be the object of 70 ~ 95% of estimated length be to guarantee steel plate that the remaining mill length of this passage is at least greater than lower passage fill full roll gap after length, namely descend the steel plate of passage in roll gap, have the asynchronous region length of load part, namely descend the contact arc length of the rolling of passage.Again due to the afterbody of this passage, reverse enter after steel, become the head of lower passage steel plate, it is now free end, steel plate rolling outlet for freely extend without restrained condition, rolling deformation is still very unstable, so the residue mill length that this passage starts afterbody pressure should be greater than more than 1.5 times of the contact arc length of lower passage.But, in steel rolling real-time control system, because information is insufficient, under direct calculating, the contact arc length of passage is more difficult, so have employed the method for adding up the passage historical data analysis of the ideal format steel plate of rolling, define 70% ~ 95% this scope that afterbody pressure length is estimated length.Concrete statistical method is as follows:

For rolled plate, the information such as size, drafts of each passage is known, and the contact arc length that can calculate I+1 passage is:

${\mathrm{cl}}_{I+1}=\sqrt{R\·({\mathrm{dh}}_{I+1}+{\mathrm{dh}}_I-{\mathrm{dh}}_{I,\mathrm{tail}})}$

Wherein, cl _i+1: the contact arc length of the rolling of I+1 passage, unit: mm; R: roller radius, unit: mm; Dh _i+1: I+1 drafts, unit: mm; Dh _i: I drafts, unit: mm; Dh _{i, tail}: I afterbody drafts, unit: mm.

And the estimated length length of I passage _ialso be known.

Using statistics software analysis can obtain lower passage contact arc length cl _i+1the value of 1 sigma level of 1.5 times be close to length _i1 ~ 95%, cl _i+1the value of 1 sigma level of 4 times be close to length _i1 ~ 70%.

Claims (1)

1. improve a milling method for bite condition in the reversable mill operation of rolling, it is characterized in that, comprise the following steps:

Step one, the ingoing ga(u)ge of this passage be rolled according to steel plate and the outgoing gauge of technological requirement set the fixed value of roller slit of this reduction in pass and correspondence thereof, and calculate steel plate adopt the fixed value of roller slit of described reduction in pass and correspondence thereof carry out this passes complete after steel plate estimated length;

Step 2, setting steel plate tail drafts is described reduction in pass 1.01 ~ 1.2 times, according to the fixed value of roller slit of described reduction in pass and correspondence thereof, steel plate is rolled, when steel plate enter steel length reach 70% ~ 95% of the steel plate estimated length described in step one time, by the roll gap of described steel plate tail drafts and correspondence thereof, steel plate is rolled, completes the rolling of this passage;

Step 3, steel plate reverse enter steel, start the rolling of lower a time.