阅读说明：本技术 一种精轧末道次压下率的控制方法 (Control method for final pass reduction rate of finish rolling ) 是由 谢居庆 陶志荣 董辉 于 2020-05-19 设计创作，主要内容包括：本发明公开了一种精轧末道次压下率的控制方法,包括以下步骤：1)L2模型根据生产信息产生道次数；2)调节末道次压下率进行拆分道次；3)与最大轧制力配合；4)在更换工作辊后,辊形前期压下率控制在18％～12％之间,辊形中期压下率控制在12％～10％之间,辊形后期压下率控制在10％～8％之间。本发明利用末道次压下率控制,量化了末道次压下率的变化,通过输入窗口设置压下率,可以对道次进行一次设定到位。(The invention discloses a control method of the final pass reduction rate of finish rolling, which comprises the following steps: 1) the L2 model generates track times according to the production information; 2) adjusting the reduction rate of the last pass to carry out splitting pass; 3) matching with the maximum rolling force; 4) after the working roll is replaced, the rolling reduction rate at the early stage of roll forming is controlled to be between 18 and 12 percent, the rolling reduction rate at the middle stage of roll forming is controlled to be between 12 and 10 percent, and the rolling reduction rate at the later stage of roll forming is controlled to be between 10 and 8 percent. The invention utilizes the last pass reduction rate control to quantify the change of the last pass reduction rate, and can set the reduction rate in place for one time through the input window.)

1. A control method of the reduction rate of the last pass of finish rolling is characterized by comprising the following steps:

1) the L2 model generates track times according to the production information;

2) adjusting the reduction rate of the last pass to carry out splitting pass;

3) matching with the maximum rolling force;

4) after the working roll is replaced, the rolling reduction rate at the early stage of roll forming is controlled to be between 18 and 12 percent, the rolling reduction rate at the middle stage of roll forming is controlled to be between 12 and 10 percent, and the rolling reduction rate at the later stage of roll forming is controlled to be between 10 and 8 percent.

2. The method of controlling a final pass reduction rate of claim 1, wherein: the production information included the intermediate billet thickness, the L2 maximum rolling force setting, and the intermediate billet steel temperature.

3. The method of controlling a final pass reduction rate of claim 1, wherein: and the adjustment of the final reduction comprises the step of calculating according to the final reduction and controlling the reduction and/or increase of the pass by combining production information.

4. The method of controlling a final pass reduction rate of finish rolling according to claim 3, wherein: the final pass reduction was calculated as:

the final pass reduction rate is (the thickness of the rolled piece before the last pass rolling-the thickness of the rolled piece after the last pass rolling) ÷ the thickness of the rolled piece before rolling multiplied by 100%.

5. The method of controlling a final pass reduction rate of claim 1, wherein: and adjusting the rolling reduction of the last pass by changing the pass number, thereby changing the rolling force to perform the matched stable rolling.

Technical Field

The invention relates to a rolling mill pass control technology at a thick plate finish rolling stage, in particular to a control method of finish rolling final pass reduction rate.

Background

The thick plate rolling process is generally divided into three stages of forming rolling, widening rolling and finish rolling. The method is characterized in that a last pass reduction rate control window is designed in a finish rolling stage, the last pass reduction rate control setting is adopted in the early stage of the roll profile of the roll, the last pass reduction rate control setting is adopted in the middle stage, the last pass reduction rate control setting is adopted in the later stage, the pass tapers are formed in different roll profile periods, pass stabilization is better realized, and the final rolling temperature hit rate of a steel plate can be adjusted through the last pass reduction rate control.

At present, during rolling, an L2 model is adopted to distribute according to temperature rolling force, and meanwhile, because a pass control technology and a roll shifting plate type control technology adopt two different control technologies, the control cannot be coordinated.

At present, the rolling target such as the final rolling temperature and the plate profile thickness of a steel plate is controlled by manually inputting a rolling force smaller than the rolling force of the existing pass to realize the pass increase from the last three-pass rolling, the last four-pass rolling or the last five-pass rolling. For example, in the automatic mode, a rolling force smaller than the average rolling force of the remaining passes is input in the manual mode when the last four passes are performed for 7 passes, and the rolling targets such as the final rolling temperature and the plate profile thickness of the steel plate are controlled by increasing the pass. However, in actual production, because the rolling force is changed by the temperature difference of the furnace train, the rolling force setting of manual experience and actual condition change of the rolling process generates deviation, too small change causes too many splitting passes, too large change causes no splitting of the pass, and although the splitting passes are successful, the rolling force is set in a critical state, after the next pass is rolled, the temperature is high, the pass is contracted to the original pass, so that the pass stability is reduced, meanwhile, the rolling force manually sets the splitting passes according to experience, so that too large rolling forces of the last passes are easy to cause the plate profile change of the steel plate, the workload in actual production is increased, the thickness change of the steel plate is large, the stability of the rolling passes is poor, and the distribution of the rolling force of the pass cannot be quantized.

In summary, in the existing rolling method, manual experience is adopted to split pass of rolling force, so that the stability of pass is reduced when the steel plate is rolled due to the influence of the split rolling force, and the plate profile of the steel plate is large.

Disclosure of Invention

In view of the above-mentioned drawbacks in the prior art, an object of the present invention is to provide a method for controlling the rolling reduction of the last pass of finish rolling, which uses the control of the rolling reduction of the last pass to quantify the change of the rolling reduction of the last pass, and sets the rolling reduction through an input window to set the pass in place at one time.

In order to achieve the purpose, the invention adopts the following technical scheme:

a control method of the reduction rate of the last pass of finish rolling comprises the following steps:

1) the L2 model generates track times according to the production information;

2) adjusting the reduction rate of the last pass to carry out splitting pass;

3) in coordination with the maximum rolling force.

4) After the working roll is replaced, the rolling reduction rate at the early stage of roll forming is controlled to be between 18 and 12 percent, the rolling reduction rate at the middle stage of roll forming is controlled to be between 12 and 10 percent, and the rolling reduction rate at the later stage of roll forming is controlled to be between 10 and 8 percent.

Preferably, the production information includes the thickness of the intermediate billet, the maximum rolling force setting of L2, and the steel temperature of the intermediate billet.

Preferably, the adjusting the final reduction comprises calculating the final reduction and controlling the reduction and/or increase according to the final reduction and the production information.

Preferably, the final reduction is calculated as:

the final pass reduction rate is (the thickness of the rolled piece before the last pass rolling-the thickness of the rolled piece after the last pass rolling) ÷ the thickness of the rolled piece before rolling multiplied by 100%.

Preferably, the last pass reduction rate is adjusted to change the pass number, so that the rolling force is changed to match with the stable rolling.

In the above technical scheme, the control method for the reduction rate of the final pass of finish rolling provided by the invention also has the following beneficial effects:

1) the control technology of the thickness of the intermediate billet, the maximum rolling force control and the last pass reduction rate can be directly used for rolling the temperature-uncontrolled steel plate without splitting passes, so that the labor intensity is reduced;

2) when the temperature is high, the reduction pass is easy to be controlled by the setting of the reduction rate of the last pass, so that the situation of the reduction pass is avoided;

3) the method integrates the requirements of rolling on the roll shape change on the reduction rate, after a new working roll is changed, the roll shape is in a concave shape due to the fact that the thermal convexity of the roll is large in the early stage and the reduction rate is 16% -12% and the thermal convexity of the roll is small in the middle stage, the reduction rate is 12% -10%, and the roll shape is in a concave shape due to abrasion in the later stage and the reduction rate is 10% -8% to match the last reduction rate with the maximum rolling force of the pass to form the most appropriate pass taper of different roll shapes.

Detailed Description

The technical scheme of the invention is further illustrated by the following examples.

The invention provides a control method of the reduction rate of the final pass of finish rolling, which comprises the following steps:

1) the L2 model generates track times according to the production information;

2) adjusting the reduction rate of the last pass to carry out splitting pass;

3) in coordination with the maximum rolling force.

4) After the working roll is replaced, the rolling reduction rate at the early stage of roll forming is controlled to be between 18 and 12 percent, the rolling reduction rate at the middle stage of roll forming is controlled to be between 12 and 10 percent, and the rolling reduction rate at the later stage of roll forming is controlled to be between 10 and 8 percent. The final pass reduction rate is (the thickness of the rolled piece before the last pass rolling-the thickness of the rolled piece after the last pass rolling) ÷ the thickness of the rolled piece before rolling multiplied by 100%

The production information included the intermediate billet thickness, the L2 maximum rolling force setting, and the intermediate billet steel temperature.

Adjusting the final reduction comprises calculating the final reduction and combining production information to control decreasing the reduction and/or increasing the pass. The calculation is specifically as follows:

the final pass reduction rate is (the thickness of the rolled piece before the last pass rolling-the thickness of the rolled piece after the last pass rolling) ÷ the thickness of the rolled piece before rolling multiplied by 100%.

For example: the thickness of the rolled piece before the penultimate pass is 24 mm, and the thickness of the rolled piece after the last pass is 20 mm, then

(24-20)÷24×100％＝16.6％

And controlling the final pass reduction rate according to the actually required rolling pass, if the control pass requires 9 passes for rolling, setting a model for 7 passes, reducing the reduction rate through an L2 final pass window, increasing the passes when the reduction rate is smaller than the reduction rate set by the model, controlling the reduction rate in the early stage of roll forming to be 18-12% through actual experience, controlling the reduction rate in the middle stage of roll forming to be 12-10%, and controlling the reduction rate in the later stage of roll forming to be 10-8%.

When the rolling force is matched with the maximum rolling force, the general maximum rolling force is set to 8200 tons and is not adjusted, the pass times can be changed by adjusting the final pass reduction rate, and the rolling force is changed by changing the final pass reduction rate to perform matched stable rolling. The maximum rolling force is generally set through the window L2 when the maximum rolling force is above 8200 tons.

Setting of rolling process data after new roll change

After the new working roll is replaced, the hot convexity of the roll in the early stage of roll forming is large, for example: the rolling is 12 multiplied by 3800 multiplied by 378000 mm, the thickness of the intermediate billet is 70 mm, the final reduction is set at 16%, the maximum rolling force is set at 8000 tons, and 9 passes of rolling are directly carried out, so that the new roll change can be realized by increasing the final rolling force, the thermal crown of the steel plate is reduced, the plate flatness of the steel plate is better, and the control setting of small-taper pass gradient is formed.

Data setting of middle rolling process of roller

After the intermediate rolling of the roller, the roller shape is formed in the early stage due to the slight convexity of the roller, such as: the rolling is carried out by 12 multiplied by 3000 multiplied by 378000 mm, the thickness of the intermediate blank is 70 mm, the final pass reduction rate is set at 12%, the maximum rolling force is set at 8000 tons, and 9 passes of rolling are directly carried out, so that the new roll change can be realized by setting the pass gradient, the final pass rolling force can be increased, the plate shape flatness of the steel plate is better, and a control setting of intermediate taper is formed.

Setting of data of later rolling process of roller

In the later stage of the roll, the roll forming in the earlier stage has been concave due to the roll profile of the roll, for example: the rolling is carried out by 12 multiplied by 2600 multiplied by 378000 mm in specification, the thickness of the intermediate billet is 70 mm, the final pass reduction rate is set at 10%, the maximum rolling force is set at 8000 tons, and 9 passes of rolling are directly carried out, so that the new roll change can be realized by increasing the final pass rolling force, reducing the reduction rate of the steel plate, controlling the final pass, controlling the rolling to be smaller, reducing the rolling force to enable the concave shape of the roll shape, improving the plate shape extension condition of the steel plate and forming a control setting of large taper pass gradient.

It should be understood by those skilled in the art that the above embodiments are only for illustrating the present invention and are not to be used as a limitation of the present invention, and that changes and modifications to the above described embodiments are within the scope of the claims of the present invention as long as they are within the spirit and scope of the present invention.