A method for unidirectional rolling of a direct-chill reversible cold rolling mill

Abstract

The application discloses a single-direction rolling method of a direct drawing type reversible cold rolling mill, and aims at providing a single-direction rolling method of a direct drawing type reversible cold rolling mill, which solves the problem that the direct drawing type reversible cold rolling mill cannot be used for single-direction rolling by properly adjusting the rolling mill and tension cylinder tension.

Description

Technical Field

[0001] This invention relates to the field of steel rolling control technology, and in particular to a unidirectional rolling method for a straight-pull reversible cold rolling mill. Background Technology

[0002] Currently, reversible rolling processes are used on straight-pull reversible cold rolling mills. However, these processes do not match the actual unidirectional rolling process on-site, resulting in significant differences in the microstructure and properties of the rolled steel sheets compared to those produced by on-site cold continuous rolling. This affects comparative studies of product mechanical properties. A simple method to achieve unidirectional rolling, using an unloaded roll gap, suffers from limitations in hydraulic components that prevent equal tension on both sides, leading to either left or right shifting of the steel strip. Using a light-pressure rolling method alters the original rolling process. Therefore, this invention patent addresses this issue by moving the lower roll upwards to create tension in the steel strip while simultaneously achieving unidirectional rolling under unloaded conditions.

[0003] Application No. 201410567482.9 discloses a stable rolling operation method for a reversible cold rolling mill, comprising the following steps: 1) Before starting each pass, adjust the tilt to a preset value, observe the rolling force difference, adjust the tilt, and control the rolling force difference between -250KN and +250KN; 2) During rolling, adjust the tilt to ensure the rolling force difference remains stable between -250KN and +250KN; 3) During the mill deceleration and tail-end rolling process, adjust the tilt according to the adjustment rule described in step 2 to ensure that the rolling force difference does not deviate significantly from that during stable rolling, and control the overflow edge of the outer ring of the steel coil; during the tail-end rolling process, pay attention to adjusting the positive bending of the work rolls. This stable rolling operation method establishes a safe and efficient handling mode for the start-up, tail-end rolling, and conventional rolling of reversible cold rolling mills, preventing accidents, reducing the workload of operators, and improving work efficiency. Its patented operating method mainly focuses on adjusting the roll gap inclination, without specifying the roll gap and steel strip tension settings, and without discussing the unidirectional rolling method.

[0004] Application No. 202110728737.5 discloses a reversible cold rolling mill process. This process involves adding a welding device between the pre-uncoiler and the inlet uncoiler. After each coil of steel is rolled, the tail of the previous coil is welded to the head of the next coil. A shearing device then cuts and separates the coil at the excessively thick tail section before proceeding with the normal rolling of the next coil. This rolling process is simple, reducing the need for strip introduction in each rolling cycle. It eliminates the need for simultaneous welding at the head and tail of the coil, requiring only one welding operation per coil, thus reducing welding time. Furthermore, this rolling method reduces the number of excessively thick rolling heads per cold-rolled coil, resulting in strip-tail-free rolling and significant economic benefits. The patented rolling process primarily involves welding the head and tail of the steel coil, thereby reducing the number of welding operations. A unidirectional strip rolling process is not included in the design.

[0005] Application No. 202310206522.6 discloses a thickness control method for a single-stand reversible cold rolling mill. The single-stand reversible cold rolling mill unit includes an inlet coiler, an outlet coiler, a mill body, a mill hydraulic system, an inlet thickness gauge, an outlet thickness gauge, an inlet speed gauge, an outlet speed gauge, an inlet tension gauge, and an outlet tension gauge. The single-stand reversible cold rolling mill unit also includes S-rolls, with S-rolls at both the inlet and outlet. The S-rolls are 180° rotatable, with the upper roll rotating to the lower roll position and the lower roll rotating to the upper roll position. This 180° rotation causes the strip steel to wind in an S-shape on the S-roll. The thickness difference of the strip steel is eliminated by adjusting the speed of the inlet S-roll to control the metal flow rate entering the roll gap. The thickness control method implemented in this patent involves adjustment and input via the S-roll, but does not involve adjusting the upward movement of the roll gap to form a certain convexity with the steel plate. Summary of the Invention

[0006] To address the problem that straight-pull reversible cold rolling mills cannot achieve unidirectional rolling, the present invention aims to provide a unidirectional rolling method for straight-pull reversible cold rolling mills. By appropriately adjusting the tension of the rolls and tension cylinder, the problem of straight-pull reversible cold rolling mills being unable to achieve unidirectional rolling is solved.

[0007] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0008] This invention discloses a unidirectional rolling method for a straight-pull reversible cold rolling mill. In the straight-pull reversible rolling mill, the upper and lower rolls move upwards while the left and right clamps move towards the rolls, creating a certain convexity in the steel plate. The steel plate between the upper and lower rolls is not subjected to rolling force, while the tension of the left and right tension cylinders remains constant. The rolls and tension cylinders rotate synchronously to move towards the initial rolling position. Then, the upper and lower rolls are moved downwards to the designed reduction amount, initiating unidirectional rolling.

[0009] Furthermore, the specific steps include the following:

[0010] Step 1: The straight-pull cold rolling mill clamps the steel plate with one side clamp and threads it, while the other side clamps it and sets the tension. The initial position of the clamp is calibrated, and the clamp and roll follow-up mode is started to complete the cold rolling mill feeding process.

[0011] Step 2: After feeding the material into the reversible cold rolling mill according to the set rolling process specifications, complete the first rolling process.

[0012] Step 3: Adjust the upper and lower rolls to move them upwards, so that the steel plate forms a certain convexity with the lower roll as the base point. At the same time, the left and right tension cylinders move synchronously towards the rolls according to the set tension and always maintain the set tension. The steel plate is not subjected to rolling force between the rolls.

[0013] Step 4: Control the rolls and left and right tension cylinders to move towards the initial rolling side and the initial calibration position of the clamps;

[0014] Step 5: Adjust the upper and lower rolls to move them down so that the roll gap of the mill is at the initial thickness position of the steel plate. At the same time, the left and right tension cylinders are automatically moved to both sides according to the set tension and the set tension is always maintained. The steel plate is not subjected to rolling force between the rolls. Adjust the steel plate to move to the left to 4-6mm away from the initial calibration position. Adjust the roll gap again to the first pass rolling thickness. The rolling force display is similar to that during the first pass rolling.

[0015] Step 6: Adjust the reduction amount of the second pass according to the rolling process, and roll according to the requirements of the second rolling process;

[0016] Repeat steps two through six above to complete the steel plate rolling.

[0017] Furthermore, in the first step, the initial position of the calibration clamp is the steel plate rolling calibration position.

[0018] Furthermore, in the fifth step, the steel plate is moved to the left to a position 5mm away from the initial calibration position.

[0019] Furthermore, in the fifth step, the steel plate is moved to the left to a position 4 mm away from the initial calibration position.

[0020] Furthermore, in the fifth step, the steel plate is moved to the left to a position 6 mm away from the initial calibration position.

[0021] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0022] The rolling method of the present invention realizes the single-sided rolling process on a straight-pull reversible cold rolling mill, thereby ensuring that the rolling process of the steel plate is consistent with the on-site process, which is beneficial to the study of various properties. Attached Figure Description

[0023] The present invention will be further described below with reference to the accompanying drawings.

[0024] Figure 1 Schematic diagram of steel plate threading and feeding;

[0025] Figure 2 This is a schematic diagram of the first rolling pass of a steel plate.

[0026] Figure 3 A schematic diagram for adjusting the upward movement of the roll gap;

[0027] Figure 4 This is a schematic diagram showing the movement of the steel plate towards the initial rolling position;

[0028] Figure 5 A schematic diagram showing the translation and adjustment of the steel plate to the first roll gap;

[0029] Figure 6 This is a schematic diagram of the second rolling process of the steel plate. Detailed Implementation

[0030] A unidirectional rolling method using a straight-pull reversible cold rolling mill involves operating the upper and lower rolls of the mill upwards while simultaneously moving the left and right clamps towards the rolls, creating a certain convexity in the steel sheet. The steel sheet between the upper and lower rolls is not subjected to rolling force, while maintaining constant tension in the left and right tension cylinders. The rolls and tension cylinders are then rotated synchronously to move towards the initial rolling position. Finally, the upper and lower rolls are moved downwards to the designed reduction amount, initiating unidirectional rolling. The specific steps include:

[0031] Step 1: The straight-pull cold rolling mill uses one-sided clamps to hold the steel plate and thread it through the roll. The other clamp, after holding the plate, sets the tension and calibrates the initial clamp position (i.e., the steel plate rolling calibration position). The clamp and roll follow-up mode is then activated to complete the cold rolling mill loading process. Figure 1 .

[0032] Step 2: After feeding the material onto the reversible cold rolling mill according to the set rolling process specifications, complete the first rolling pass, such as... Figure 2 .

[0033] Step 3: Adjust the upper and lower rolls to move them upwards, so that the steel plate forms a certain convexity with the lower roll as the base point. Simultaneously, the left and right tension cylinders automatically move synchronously towards the rolls according to the set tension, maintaining the set tension at all times. The steel plate is not subjected to rolling force between the rolls. Figure 3 .

[0034] Step 4: Control the rolls and left and right tension cylinders to move towards the initial rolling side and the initial clamping position. For example... Figure 4 .

[0035] Step 5: Adjust the upper and lower rolls to lower the mill roll gap to the initial thickness position of the steel plate. Simultaneously, the left and right tension cylinders automatically move synchronously to both sides according to the set tension, maintaining the set tension at all times. The steel plate is not subjected to rolling force between the rolls. Adjust the steel plate to move to the left until it is 5mm away from the initial calibration position. Adjust the roll gap again to the thickness of the first pass rolling. The rolling force display should be similar to that during the first pass rolling. Figure 5 .

[0036] Step 6: Adjust the reduction amount for the second pass according to the rolling process, and perform rolling according to the requirements of the second pass rolling process, such as... Figure 6 .

[0037] Repeat steps two through six above to complete the steel plate rolling.

[0038] Taking Q235 carbon steel as an example, this describes the single-sided rolling process of a straight-pull reversible cold rolling mill. First, the Q235 steel plate undergoes surface treatment to reveal its natural steel color (bright white). Then, the plate is flattened to ensure it remains straight. After completing these steps, assuming the right-side clamping clamps the plate for loading, the single-sided rolling process of the straight-pull reversible cold rolling mill is implemented according to the following steps.

[0039] The steel plate is clamped by the right clamp of the cold rolling mill → the strip is fed into the direct-pull reversible cold rolling mill → the steel plate is clamped by the left clamp of the cold rolling mill → the initial position of the right clamp is marked → the final rolling position of the left clamp is marked → the process tension is set → the roll and tension cylinder follow-up mode is started → the reduction is adjusted → the rolling is controlled to the right to complete the first pass → the upper and lower rolls are moved up (no rolling force between the rolls) → the left and right tension cylinders are controlled to move the rolls to the left according to the set tension → the roll gap between the upper and lower rolls is moved down to the initial steel plate thickness → the workpiece is finely adjusted to 5mm before the initial marking position of the right clamp → the upper and lower rolls are moved down to complete the second pass reduction → the rolling is controlled to the right to complete the second pass → the above process is repeated to complete the entire cold rolling process.

[0040] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A unidirectional rolling method using a straight-pull reversible cold rolling mill, characterized in that: In the operation of a straight-pull reversible rolling mill, the upper and lower rolls move upwards, while the left and right clamps move towards the rolls, creating a certain convexity in the steel plate. The steel plate between the upper and lower rolls is not subjected to rolling force, and the tension of the left and right tension cylinders is kept constant. The rolls and tension cylinders rotate synchronously to move towards the initial rolling position. Then, the upper and lower rolls are moved downwards to the designed reduction amount to start single-sided rolling. Specifically, the steps include the following: Step 1: The straight-pull cold rolling mill clamps the steel plate with one side clamp and threads it, while the other side clamps it and sets the tension. The initial position of the clamp is calibrated, and the clamp and roll follow-up mode is started to complete the cold rolling mill feeding process. Step 2: After feeding the material into the reversible cold rolling mill according to the set rolling process specifications, complete the first rolling process. Step 3: Adjust the upper and lower rolls to move them upwards, so that the steel plate forms a certain convexity with the lower roll as the base point. At the same time, the left and right tension cylinders move synchronously towards the rolls according to the set tension and always maintain the set tension. The steel plate is not subjected to rolling force between the rolls. Step 4: Control the rolls and left and right tension cylinders to move towards the initial rolling side and the initial calibration position of the clamps; Step 5: Adjust the upper and lower rolls to move them down so that the roll gap of the mill is at the initial thickness position of the steel plate. At the same time, the left and right tension cylinders are automatically moved to both sides according to the set tension and the set tension is always maintained. The steel plate is not subjected to rolling force between the rolls. Adjust the steel plate to move to the left to 4-6mm away from the initial calibration position. Adjust the roll gap again to the first pass rolling thickness. The rolling force display is similar to that during the first pass rolling. Step 6: Adjust the reduction amount of the second pass according to the rolling process, and roll according to the requirements of the second rolling process; Repeat steps two through six above to complete the steel plate rolling.

2. The unidirectional rolling method of a direct-draw reversible cold rolling mill according to claim 1, characterized in that: In the first step, the initial position of the calibration clamp is the steel plate rolling calibration position.

3. The unidirectional rolling method of a direct-draw reversible cold rolling mill according to claim 1, characterized in that: In the fifth step, the steel plate is moved to the left to a position 5 mm away from the initial calibration position.

4. The unidirectional rolling method of a direct-draw reversible cold rolling mill according to claim 1, characterized in that: In the fifth step, the steel plate is moved to the left to a position 4 mm away from the initial calibration position.

5. The unidirectional rolling method of a direct-draw reversible cold rolling mill according to claim 1, characterized in that: In the fifth step, the steel plate is moved to the left to a position 6 mm away from the initial calibration position.

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