CN-115243807-B - Tool and method for changing work rolls in a rolling mill

Abstract

The invention relates to a method for changing a work roll (12) in a rolling mill, which method limits the risk of scraping the work roll (12), even a metal strip, when the work roll (12) is removed or inserted, by means of mechanical separating members, in particular branches (20, 21) of a bifurcation system, which are inserted by robotic members.

Inventors

• Conrad Ernst de la GreTai

Assignees

• 法孚斯德姆斯公司
• 法孚斯德姆斯公司

Dates

Publication Date

20260421

Application Date

20210309

Priority Date

20200310

Claims (20)

1. 1. A method of changing work rolls (12) of a rolling mill (10), for a Metal Strip (MS) to be rolled between two work rolls (12), the work rolls comprising an upper work roll and a lower work roll, and wherein in a closed position of a roll stand configured to roll the Metal Strip (MS), the work rolls (12) each have a contact busbar with the metal strip, the contact busbars and the axes of the work rolls being located in a plane substantially perpendicular to the running direction of the metal strip, rolling members are in contact along two contact busbars between each work roll (12) and the rolling members, the rolling members ensuring that rolling forces are transmitted to the lower work roll and upper work roll (12) in contact with the Metal Strip (MS), a method of ensuring removal of the work rolls (12) from the roll stand after at least partially opening the roll stand by performing the following steps on the upper work roll and/or lower work roll, wherein in the closed position of the roll stand, the work rolls (12) are spaced apart from each other with respect to the work roll stand position: -an insertion step a) comprising: -robotically inserting a mechanical separation member (1) between the work roll (12) and the Metal Strip (MS) into a separation position (SP 1), wherein the Metal Strip (MS) and the work roll (12) are physically separated along the length of the work roll and until contact between the work roll (12) and the Metal Strip (MS) is ensured to be removed, and/or -Robotically inserting a mechanical separation member (1) between the work roll (12) and the rolling component into a separation position (SP 2), wherein the work roll (12) and the rolling component are physically separated along the length of the work roll until contact between the work roll (12) and the rolling component is ensured to be inhibited -A removal step b) comprising: -robotically extracting the work roll (12) by gripping the end of the work roll (12) and moving the work roll along its axis with respect to the Metal Strip (MS) and the rolling components present in the roll stand, wherein the mechanical separation means: -in the separation position (SP 1), wherein the work roll (12) and the Metal Strip (MS) are physically separated to avoid any friction between the work roll and the metal strip when moving, or/and -In said separated position (SP 2), wherein said work rolls (12) and said rolling members are physically separated, so as to avoid any friction between said work rolls and said rolling members when moving.
2. 2. A method according to claim 1, having the inserting step a), comprising robotically inserting the mechanical separation member between the upper or lower work roll (12) and the Metal Strip (MS) to the separation position (SP 1), wherein the Metal Strip (MS) and the upper or lower work roll (12) are physically separated along the length of the work roll, thereby ensuring that contact between the work roll and the metal strip is inhibited, and ensuring removal, wherein the removal of the work roll is performed robotically by moving the work roll along the axis of the work roll (12) relative to the metal strip and the rolling member, in the separation position (SP 1) the upper or lower work roll (12) and the Metal Strip (MS) are physically separated so as to avoid any friction between the work roll and the metal strip when moving.
3. 3. Method according to claim 2, characterized in that the inserting step a) and the withdrawing step b) are carried out for the upper work roll (12), and in that the separating member (1) between the upper work roll (12) and the Metal Strip (MS) comprises a bifurcation system (2) comprising two branches (20, 21) held to the same bifurcation carriage (22) parallel to each other, and in that the two branches of the bifurcation system are movable with respect to the bifurcation carriage to assume, on the one hand, a spaced-apart position (SAP) configured to ensure that the two branches of the bifurcation are inserted on either side of the upper work roll without friction with the upper work roll (12) still contacting the metal strip via contact buses, and, on the other hand, a Closed Position (CP), in which the two branches of the bifurcation system are moved closer to each other, configured to contact the two buses of the upper work roll (12) respectively, to inhibit the upper work roll from contacting the Metal Strip (MS) by lifting the upper work roll.
4. 4. Method according to claim 2, characterized in that the inserting step a) and the withdrawing step b) are performed for the lower work roll, and in that the separating member between the work roll and the metal strip comprises a bifurcation system (2) comprising two branches (20, 21) held to the same bifurcation carriage (22) parallel to each other, and in that the two branches of the bifurcation system have free ends (23) with inclined surfaces (24) which are inclined with respect to the plane of the Metal Strip (MS) in a direction perpendicular to the running direction of the metal strip when the two branches (20, 21) of the bifurcation system have axes comprised in the plane parallel to the plane of the Metal Strip (MS), the inclined surfaces (24) at the ends of the branches (21) being configured to cooperate with the edges of the Metal Strip (MS) to lift the metal strip (12) with a movement parallel to the direction of the lower work roll when the branches (20, 21) are inserted, wherein the metal strip (12) is spaced apart from the lower work roll (12) and is inhibited from contacting the lower work roll (12).
5. 5. A method according to claim 3, characterized in that the two branches (20, 21) of the branching system (2) have a cross-section in a plane perpendicular to the direction of the branches (20, 21), which cross-section comprises two inclined planes (25, 26) belonging respectively to the two branches (20, 21) facing each other, which inclined planes are inclined in the running direction of the metal strip with respect to the plane of the Metal Strip (MS), which inclined planes (25, 26) are configured to be in contact with the two generatrix of the upper work roll (12) to ensure lifting of the upper work roll, so that a bracket for holding the upper work roll (12) is formed in the Closed Position (CP) of the branches (20, 21) of the branching system (2).
6. 6. The method according to any one of claims 1 to 5, wherein the inserting step a) comprises: -robotically inserting the mechanical separation member (1) between the work roll (12) and the Metal Strip (MS) into the separation position (SP 1), wherein the Metal Strip (MS) and the work roll (12) are physically separated along the length of the work roll and until contact between the work roll (12) and the Metal Strip (MS) is ensured to be inhibited, and Said mechanically separating means between said work rolls (12) and said rolling members being robotically inserted into said separating position (SP 2), wherein said work rolls and said rolling members are physically separated along the length of said work rolls until contact between said work rolls and said rolling members is ensured to be inhibited, And wherein the removing step b) comprises robotically extracting the work roll by gripping one end of the work roll and moving the work roll along its axis with respect to the metal strip and the rolling component, and wherein the mechanical separating member (1): -in the separation position (SP 1), wherein the work roll (12) and the metal strip (123) are physically separated, so as to avoid any friction between the work roll and the metal strip when moving, and simultaneously -In said separated position (SP 2), wherein said work rolls (12) and said rolling members are physically separated, so as to avoid any friction between said work rolls and said rolling members when moving.
7. 7. The method as claimed in claim 6, characterized in that the inserting step a) and the withdrawing step b) are carried out for the upper work roll (12), and in that the separating member (1) between the upper work roll (12) and the Metal Strip (MS) comprises a bifurcation system (2) comprising two branches (20, 21) held to the same bifurcation carriage (22) parallel to each other, and in that the two branches of the bifurcation system are movable with respect to the bifurcation carriage to assume, on the one hand, a spaced-apart position (SAP) configured to ensure the insertion of the two branches of the bifurcation on either side of the upper work roll without friction with the upper work roll (12) still contacting the metal strip via contact buses, and, on the other hand, a Closed Position (CP), in which the two branches of the bifurcation system are moved closer to each other, configured to contact the two buses of the upper work roll (12) respectively, to inhibit the upper work roll from contacting the Metal Strip (MS) by lifting the upper work roll, Or alternatively Wherein the inserting step a) and the withdrawing step b) are performed for the lower work roll, and wherein the separating member between the work roll and the metal strip comprises a bifurcation system (2) comprising two branches (20, 21) parallel to each other held to the same bifurcation carriage (22), and wherein both branches of the bifurcation system have free ends (23) with inclined surfaces (24) which are inclined with respect to the plane of the Metal Strip (MS) in a direction perpendicular to the running direction of the metal strip when both branches (20, 21) of the bifurcation system have axes contained in a plane parallel to the plane of the Metal Strip (MS), the inclined surfaces (24) at the ends of the branches (21) being configured to lift the metal strip in cooperation with movement parallel to the direction of the lower work roll upon insertion of the branches (20, 21), wherein the Metal Strip (MS) is lifted from the lower work roll (12) and inhibited from contacting the metal strip (12) between the lower work roll (12), And wherein the separation means between the work roll and the metal strip comprise the bifurcation system (2) comprising two branches (20, 21) which are movable relative to each other from a position (SAP) in which they are spaced apart to the Closed Position (CP), wherein the two branches (20, 21) of the bifurcation system are interposed between the upper or lower work roll (12) and the Metal Strip (MS) so as to ensure that contact between the work roll (12) and the Metal Strip (MS) is inhibited, and wherein the mechanical separation means between the work roll (12) and the rolling part comprise two wings (3, 4) with an interposed function which are respectively hinged to the two branches (20, 21) of the bifurcation system and at the same time ensure that mechanical separation between the work roll and the rolling part is ensured when the two branches are moved from the position (SAP) in which they are spaced apart to their Closed Position (CP), wherein the physical contact between the work roll (12) and the rolling part is inhibited along the length of the work roll (12) by the wings (3, 4) being interposed.
8. 8. Method according to any one of claims 1 to 5, characterized in that clamping the end of the work roll (12) during the removing step b) is performed by a clamping device (5) configured to clamp the end of the work roll, the clamping device comprising a gripper (50) with an electromagnetic or pneumatic suction cup cooperating with the base of the roll, or a clamp with a grip, the grip engaging the cylindrical periphery of the end of the roll, and wherein the removing step b) is performed by moving the gripper (50) in the direction of the work roll, thereby ensuring pulling of the work roll (12).
9. 9. The method as claimed in claim 8, characterized in that the inserting step a) and the withdrawing step b) are carried out for the upper work roll (12), and in that the separating member (1) between the upper work roll (12) and the Metal Strip (MS) comprises a bifurcation system (2) comprising two branches (20, 21) held to the same bifurcation carriage (22) parallel to each other, and in that the two branches of the bifurcation system are movable with respect to the bifurcation carriage to assume, on the one hand, a spaced-apart position (SAP) configured to ensure the insertion of the two branches of the bifurcation on either side of the upper work roll without friction with the upper work roll (12) still contacting the metal strip via contact buses, and, on the other hand, a Closed Position (CP), in which the two branches of the bifurcation system are moved closer to each other, configured to contact the two buses of the upper work roll (12) respectively, to inhibit the upper work roll from contacting the Metal Strip (MS) by lifting the upper work roll, Or alternatively Wherein the inserting step a) and the withdrawing step b) are performed for the lower work roll, and wherein the separating member between the work roll and the metal strip comprises a bifurcation system (2) comprising two branches (20, 21) parallel to each other held to the same bifurcation carriage (22), and wherein both branches of the bifurcation system have free ends (23) with inclined surfaces (24) which are inclined with respect to the plane of the Metal Strip (MS) in a direction perpendicular to the running direction of the metal strip when both branches (20, 21) of the bifurcation system have axes contained in a plane parallel to the plane of the Metal Strip (MS), the inclined surfaces (24) at the ends of the branches (21) being configured to lift the metal strip in cooperation with movement parallel to the direction of the lower work roll upon insertion of the branches (20, 21), wherein the Metal Strip (MS) is lifted from the lower work roll (12) and inhibited from contacting the metal strip (12) between the lower work roll (12), And wherein the gripping device (5) further comprises the gripper (50) and further comprises an actuator (51) connecting the bifurcated stent (22) to the gripper (50), the actuator being configured to move the gripper (50) relative to the bifurcated stent (22) along a direction parallel to the branches of the bifurcated system, the removing step b) comprising: A first removal sub-step, in which the gripper (50) grips the end of the work roll (12) and performs a partial removal of the work roll (12) with respect to the bifurcation system by moving the work roll (12) along the branches (20, 21) of the bifurcation system, the branches (12) of the bifurcation system being fixed in the roll stand (10) in the Closed Position (CP), A second removal sub-step in which a support element (6) movable in a direction perpendicular to the direction of the branches and connected to the support by a second actuator 60 is engaged with the periphery of the work roller in the vicinity of the clamped end, so as to ensure locking clamping of the work roller between, on the one hand, the motor-driven support element (6) and, on the other hand, the counter-support element (7) in the vicinity of the bifurcated support (12), -A third removal sub-step, in which the work rolls locked between the support element (6) and the counter-support element (7) are completely removed from the roll stand by moving the whole of the branching system and the locked work rolls.
10. 10. The method according to claim 9, characterized in that the bifurcation system (2), the gripping device (5) further comprises the gripper (50), and further comprises an actuator (51) connecting the stand of the bifurcation system to the gripper, and that the support element (6) connected to the stand by the second actuator 60 is a self-supporting assembly processed by a robotic member (Ro) forming the same work roll changing tool (8).
11. 11. The method of claim 10, wherein the upper work roll and the lower work roll are continuously removed by the same work roll change tool handled by a robotic means (Ro) comprising means for moving the self-supporting assembly: During the insertion step or the removal step, in an x-direction parallel to the axis of the work roll (12) to be clamped, At a height along the z-direction to move from a position allowing removal of the upper work roll to a position allowing removal of the lower work roll, -Pivoting along a rotation axis parallel to the direction of the branches of the bifurcation system to move from a configuration allowing the self-supporting assembly of the upper work roll to be extracted to a configuration in which the self-supporting assembly of the lower work roll can be extracted by 180 °.
12. 12. The method of claim 1, wherein the rolling mill is a20 HI rolling mill.
13. 13. A method of changing the work rolls (12) of a rolling mill (10), the method being used in the presence of a Metal Strip (MS) to be rolled between two work rolls (12), the work rolls comprising an upper work roll and a lower work roll, and wherein in a closed position of a roll stand configured to roll the Metal Strip (MS), the work rolls (12) each have a contact busbar with the metal strip, the contact busbars and the axes of the work rolls lying in a plane substantially perpendicular to the running direction of the metal strip, rolling members being in contact along two contact busbars between each work roll (12) and the rolling members, the rolling members ensuring the transmission of rolling forces to the lower work roll and upper work roll (12) in contact with the Metal Strip (MS), a method of inserting a new or ground work roll (12) into the roll stand after at least partially opening the roll stand by performing the following steps on the upper work roll and/or lower work roll. -An insertion step c), comprising: -robotically inserting a mechanical separating member (1) between the Metal Strip (MS) and the work roll to be inserted, thereby ensuring that contact between the work roll (12) and the Metal Strip (MS) is inhibited, and/or -Robotically inserting a mechanical separating member (1) between the rolling member and the work roll (12) to be inserted, ensuring that contact between the work roll (12) and the rolling member is inhibited, -An insertion step d) which consists in robotically inserting the work rolls (12) simultaneously with or after the insertion step c), by pushing one end of the work rolls (12) and moving the work rolls along their axes with respect to the Metal Strip (MS) and the rolling components present in the roll stand, wherein the mechanical separation means: -in a separation position (SP 1) in which the work roll (12) and the Metal Strip (MS) are physically separated, to avoid any friction between the work roll and the metal strip when moving, or/and -In a separated position (SP 2) in which the work rolls (12) and the rolling members are physically separated, so as to avoid any friction between the work rolls and the rolling members when moving.
14. 14. A method according to claim 13, having the inserting step c), comprising robotically inserting a mechanical separation member between the upper or lower work roll (12) to be inserted and the Metal Strip (MS) to the separation position (SP 1), wherein the Metal Strip (MS) and the upper or lower work roll (12) are physically separated along the length of the work roll, thereby ensuring that contact between the work roll and the metal strip is inhibited, and having the inserting step d), wherein the inserting of the work roll is performed robotically in the separation position (SP 1) by moving the work roll along the axis of the work roll (12) relative to the metal strip and the rolling member, wherein the upper or lower work roll (12) and the Metal Strip (MS) are physically separated so as to avoid any friction between the work roll and the metal strip when moving.
15. 15. Method according to claim 13, characterized in that the inserting step a) and the inserting step d) are carried out for the upper work roll (12), and in that the separating member (1) between the upper work roll (12) and the Metal Strip (MS) comprises a bifurcation system (2) comprising two branches (20, 21) held to the same bifurcation carriage (22) parallel to each other, and in that the two branches of the bifurcation system are movable with respect to the bifurcation carriage to assume, on the one hand, a Closed Position (CP) during the inserting step c) and the inserting step d), in which the branches of the bifurcation system are moved closer to each other, the closed position being configured to be in contact with the two busbars of the upper work roll (12) respectively to space the upper work roll from the Metal Strip (MS), and, on the other hand, to assume a spaced-apart position (SAP) configured to place the upper work roll (12) on the metal strip with contact busbars between the upper work roll and the metal strip, and then being arranged on either side of the two branches.
16. 16. Method according to claim 14, characterized in that the inserting step c) and the inserting step d) are performed for the lower work roll, and in that the separating member between the work roll and the metal strip comprises a bifurcation system (2) comprising two branches (20, 21) held to the same bifurcation carriage (22) parallel to each other, and in that the two branches of the bifurcation system have free ends (23) with inclined surfaces (24) which are inclined with respect to the plane of the Metal Strip (MS) in a direction perpendicular to the running direction of the metal strip when the two branches (20, 21) of the bifurcation system have axes comprised in a plane parallel to the plane of the Metal Strip (MS), the inclined surfaces (24) at the ends of the branches (21) being configured to cooperate with the edges of the Metal Strip (MS) to lift the metal strip (12) with a movement parallel to the direction of the lower work roll when the branches (20, 21) are inserted.
17. 17. Method according to claim 15 or 16, characterized in that the two branches (20, 21) of the bifurcation system (2) have a cross-section in a plane perpendicular to the direction of the branches (20, 21), which cross-section comprises two inclined planes (25, 26) belonging to the two branches (20, 21) facing each other, respectively, which inclined planes are inclined with respect to the plane of the Metal Strip (MS) along the running direction of the metal strip, the two inclined planes (25, 26) being configured to be in contact with the two generatrix of the upper work roll (12) to ensure the holding of the upper work roll, so that a bracket for holding the upper work roll (12) is formed in the Closed Position (CP) of the branches (20, 21) of the bifurcation system (2), and then the upper work roll is placed onto the metal strip in a controlled manner when the two branches are moved to their Spaced Apart Positions (SAP).
18. 18. The method according to any one of claims 13 to 16, wherein the inserting step c) comprises: -said robotically inserting said mechanical separation member (1) between said Metal Strip (MS) and said work roll to be inserted, thereby ensuring that contact between said work roll (12) and said Metal Strip (MS) is inhibited, and -Said step of inserting mechanically a mechanical separation member (1) between said rolling component and said work roll (12) to be inserted, ensuring the inhibition of the contact between said work roll (12) and said rolling component And wherein the inserting step d) comprises robotically inserting the work rolls by pushing one end of the work rolls and moving the work rolls along their axes with respect to the metal strip and the rolling part, and wherein the mechanical separating member (1): -in the separation position (SP 1), wherein the work roll (12) and the Metal Strip (MS) are physically separated to avoid any friction between the work roll and the metal strip when moving, and simultaneously -In said separated position (SP 2), wherein said work rolls (12) and said rolling members are physically separated, so as to avoid any friction between said work rolls and said rolling members when moving.
19. 19. The method according to claim 18, characterized in that the inserting step a) and the inserting step d) are carried out for the upper work roll (12), and in that the separating member (1) between the upper work roll (12) and the Metal Strip (MS) comprises a bifurcation system (2) comprising two branches (20, 21) held to the same bifurcation carriage (22) parallel to each other, and in that the two branches of the bifurcation system are movable with respect to the bifurcation carriage to assume, on the one hand, a Closed Position (CP) during the inserting step c) and the inserting step d), in which the branches of the bifurcation system are moved closer to each other, the closed position being configured to be in contact with two busbars of the upper work roll (12) respectively to space the upper work roll from the Metal Strip (MS), and, on the other hand, to assume a spaced-apart position (SAP) configured to place the upper work roll (12) on the metal strip with contact busbars between the upper work roll and the metal strip, and then on either side of the two branches, Or alternatively Wherein the inserting step c) and the inserting step d) are performed for the lower work roll, and wherein the separating member between the work roll and the metal strip comprises a bifurcation system (2) comprising two branches (20, 21) held to the same bifurcation carriage (22) parallel to each other, and wherein both branches of the bifurcation system have free ends (23) with inclined surfaces (24) which are inclined with respect to the plane of the Metal Strip (MS) in a direction perpendicular to the running direction of the metal strip when both branches (20, 21) of the bifurcation system have axes contained in a plane parallel to the plane of the Metal Strip (MS), the inclined surfaces (24) at the ends of the branches (21) being configured to cooperate with the edges of the Metal Strip (MS) to lift the Metal Strip (MS) with a movement parallel to the direction of the lower work roll upon insertion of the branches (20, 21), wherein the Metal Strip (MS) is lifted from the lower work roll (12), The separation means between the work roll and the metal strip comprise the bifurcation system (2) comprising two branches (20, 21) which are movable relative to each other from a Closed Position (CP), wherein the two branches (20, 21) of the bifurcation system are interposed between the upper or lower work roll (12) and the Metal Strip (MS) ensuring that contact between the work roll (12) and the Metal Strip (MS) is inhibited during the insertion step c) and the insertion step d), and wherein the mechanical separation means between the work roll (12) and the rolling part comprise two wings (3, 4) with an insertion function, which are integral with the two branches (20, 21) of the bifurcation system, respectively, in an articulated manner, and at the same time ensure that in the Closed Position (CP) the work roll is mechanically separated from the rolling part, wherein the work roll (12) and the rolling part ensure that contact between the insertion step c) and the rolling part is inhibited by the wings (3, 4) physically separating along the length of the work roll.
20. 20. Method according to claim 19, characterized in that the insertion step c) and the insertion step d) are carried out for the upper work roll (12), and in that the separation member (1) between the upper work roll (12) and the Metal Strip (MS) comprises the bifurcation system (2) comprising two branches (20, 21) held to the same bifurcation stand (22) parallel to each other, and in that the two branches of the bifurcation system are movable with respect to the bifurcation stand to assume, on the one hand, a Closed Position (CP) during the insertion step c) and the insertion step d), in which the two branches of the bifurcation system are moved closer to each other, the closed position being configured to contact the two busbars of the upper work roll (12) to space the upper work roll from the Metal Strip (MS), the two wings (3, 4) simultaneously ensuring a mechanical separation between the work roll (12) and the rolling part, and then assuming, on the other hand, a spaced-apart position (SAP), the positions being configured to ensure a mutual retraction of the upper work roll from the lower work roll (12) to the metal strip, the foil being placed on either side of the upper work roll (12) at the same time, where they release the gap between the work rolls and the rolling member.

Description

Tool and method for changing work rolls in a rolling mill The invention relates to a method for changing the work rolls of a rolling mill in the presence of a metal strip to be rolled between two work rolls, said work rolls comprising an upper work roll and a lower work roll, said method being suitable for removing the work rolls from a roll stand. The invention further relates to a method for changing the work rolls of a rolling mill in the presence of a metal strip to be rolled between two work rolls, said work rolls comprising an upper work roll and a lower work roll, said method being suitable for inserting and placing the lower work roll or the upper work roll, in particular a new or ground work roll. The present disclosure further relates to a work roll changing tool configured for performing a work roll changing operation adapted for removing work rolls and/or for inserting and placing upper work rolls and/or lower work rolls, in particular new or ground work rolls, in a roll stand. Technical Field Thus, the present invention finds advantageous application in multi-roll rolling mills, typically "Sendzimir" rolling mills. Cold rolling can obtain the final thickness of this strip by passing a metal strip continuously between the rolls in the presence of both high pressure and traction. A "Sendzimir" type rolling mill comprises a plurality of rolls or rollers arranged relative to each other to allow varying the mechanical characteristics of the metal strip and to obtain a strip thickness that may be less than 3 millimeters. More precisely, a "Sendzimir" rolling mill is known which may comprise twenty rolls, an exemplary embodiment of which is illustrated in US 5 193 377 and US 5 471 859. Fig. 12 shows a schematic of a cross section of a twenty high rolling mill. In this figure the rolls are divided into a lower group LG and an upper group UG, more precisely those groups LG and UG having a symmetrical structure and each comprising ten rolls, wherein a work roll 12, two first intermediate rolls 13, three second intermediate rolls 14 and 15 and four support rolls or backing rolls, which are outside the arrangement and are denoted by A, B, C and D in the upper group UG and E, F, G, H in the lower group LG. This nomenclature for the various rolls that make up a twenty-high rolling mill is conventional in the mill art and is well known to those skilled in the art. It is recognized in the mill art that such a roll arrangement illustrated in fig. 12 allows for efficient operation of the metal strip MS to achieve a desired strip thickness. Because of the stresses imposed on the work rolls 12 and the very periodic maintenance required of these components 12 in processing the metal strip MS, it is desirable to be able to quickly and safely remove and replace the work rolls 12 for the operator. In a 20-roll ("20 Hi") rolling mill, it is still noted that the opening of the stands is small, in particular when the roll stands are one-piece, since in this case only obtained by the support rollers being pivoted eccentrically outwards (A, B, C, D for the upper group UG and E, F, G, H for the lower group LG). According to the findings of the inventors, there is a great risk of collision and friction between the work rolls during their removal (or insertion) and the components of the surrounding rolling mill (for example the first two intermediate rolls 13, or even the metal strip MS present in the stand). It is desirable to be able to replace the work rolls during the removal step or when a new or ground work roll is placed in the roll stand without marking the metal strip, without deteriorating the surface conditions of the work rolls, or even replacing the first intermediate roll. Accordingly, the present disclosure is particularly useful for replacing work rolls of cold rolling mills, typically used to perform bright annealing. In this rolling mill, the work rolls have so-called mirror-polished surface conditions at very low roughness. Background Based on the applicant's knowledge robotic systems are known from the prior art, for example multiaxial arms equipped with grippers configured to ensure removal of the rolls from the rolling mill. These robotic systems allow the removal of the rolls from the mill with minimal risk of injury to the operator compared to elevator conversion methods that require the operator to be physically present near the work rolls being processed to remove the rolls and replace them with new or ground rolls However, based on the findings of the inventors, none of the known robotic systems can guarantee a safe removal (or insertion) of the work rolls in a 20Hi rolling mill, avoiding the risk of marking between the work rolls (on the one hand) and the metal strip, or even the first intermediate roll (on the other hand). Disclosure of Invention The present disclosure improves the situation. According to a first aspect, a method for changing the work rolls of a rolling mill in the presence of a m