# US 8,539,804 B2 · Method and device for controlling a roll gap > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,539,804 B2 - Document ID: US8539804B2 - Status: Granted - Kind: B2 - Application number: 12/308,961 - Filed: 2007-05-21 - Published: 2009-11-12 - Granted: 2013-09-24 - Earliest claimed: 2006-06-30 - Assignees: ABB AB - Applicants: Lars Jonsson - Inventors: Lars Jonsson - Web page: https://patentgrep.com/patent/US8539804B2 ## CPC - B21B 37/28: Control of flatness or profile during rolling of strip, sheets or plates - B21B 37/16: Control of thickness, width, diameter or other transverse dimensions (B21B37/58 takes precedence) - B21B 37/58: Roll-force control; Roll-gap control {(B21B38/105 takes precedence)} - B21B 37/62: by control of a hydraulic adjusting device - B21B 38/04: for measuring thickness, width, diameter or other transverse dimensions of the product - B21B 2263/02: Profile, e.g. of plate, hot strip, sections - B21B 2271/02: Roll gap, screw-down position, draft position - B21B: ROLLING OF METAL (auxiliary operations used in connection with metal-working operations covered in B21, see B21C; bending by rolling B21D; manufacture of particular objects, e.g. screws, wheels, rings, barrels, balls, by rolling B21H; pressure welding by means of a rolling mill B23K20/04) ## Abstract The invention relates to a method and a device for controlling a roll gap when rolling a strip (1) in a rolling mill including at least two rolls (3a-b,4a-b), and at least two roll gap actuators (6,7) that independently control the size of the roll gap. The device is adapted to receive information on the amount of wedge shape (POSactOS,POSactDS) in the strip thickness profile across the strip width, and to control said actuators, based on said information on the amount of wedge shape in the strip thickness profile, such that the relative reduction of the strip on both sides of the rolling mill become essentially the same. ## Claims ### Claim 1 A method for controlling a roll gap when rolling a strip (1) having lateral edges in a rolling mill including at least two rolls (3a-b,4a-b), and at least two roll gap actuators (6,7) positioned to be adjacent the respective lateral edges of the strip (1) and which independently control size of the roll gap, wherein the method comprises the steps of: receiving information on amount of wedge shape (H, POSactOS, POSactDS) in strip thickness profile across strip width, determining relative reduction of the strip (1) by the formulas Δh/H or Δh/h, where Δh=H−h, with H denoting thickness of the strip (1) before entering the roll pap and h denoting thickness of the strip after passing through the roll gap, and based thereon, controlling said actuators (6, 7) such that the relative reduction (Δh) of the strip (1) at both edges of the strip (1) is substantially identical. ### Claim 2 (depends on 1) The method according to claim 1, wherein said information on the amount of wedge shape includes information on thickness profile (H) across the strip width of the strip to be rolled. ### Claim 3 (depends on 1) The method according to claim 1, wherein said rolling mill further includes a thickness control system (42), which calculates a thickness correction (POSadd) for the roll gap based on a desired strip thickness (href), and the method comprises: receiving information on the thickness correction (POSadd) to be done, and controlling said actuators (6,7), based on the thickness correction and the amount of wedge shape in the strip thickness (POSactOS, POSactDS) such that relative thickness corrections at both edges of the strip (1) are substantially identical. ### Claim 4 (depends on 3) The method according to claim 3, wherein said roll gap actuators (6,7) independently control the size of the roll gap on an operator side of the mill adjacent one the lateral edges of the strip (1) and on a drive side of the mill adjacent the other later edge of the strip (1), and the method comprises computing a thickness correction (POSaddOS) to be applied to the roll gap actuator on the operator side and a thickness correction (POSaddDS) to be applied to the roll gap actuator on the operator side based on the thickness correction and the amount of wedge shape in the strip thickness. ### Claim 5 (depends on 4) The method according to claim 4, wherein desired size dOS of the roll gap on the operator side is calculated based on the following equation: d OS = Δ ⁢ ⁢ hc Hc * H OS , where HOS is the strip thickness on the operator side before rolling, Hc is the strip thickness at the center of the strip before rolling, and Δhc is the change in thickness at the center of the strip after rolling, and desired size dDS of the roll gap on the drive side is calculated based on the following equation: d DS = Δ ⁢ ⁢ hc Hc * H DS , where HDS is the strip thickness on the drive side before rolling. ### Claim 6 (depends on 4) The method according to claim 4, wherein the thickness corrections are determined by the formula POSaddOS=2POSadd−POSaddDS. ### Claim 7 (depends on 1) The method according to claim 1, wherein the method comprises: receiving information on thickness of the strip before rolling the strip at least at two points (15a-c) across the width of the strip, receiving information on thickness of the strip after rolling the strip at least at one point (13) across the width of the strip, computing a relative reduction of the strip based on the thickness of the strip before and after rolling, and controlling said actuators (6,7) based on the computed relative reduction of the strip and said information on the thickness of the strip before rolling the strip at least at two points. ### Claim 8 (depends on 7) The method according to claim 7, wherein said roll gap actuators independently control the size of the roll gap on an operator side of the mill adjacent one of the lateral edges of the strip (1) and on a drive side of the mill adjacent the other lateral edge of the strip (1) and the method comprises estimating a desired roll gap on the operator side of the mill based on the computed relative reduction of the strip and thickness of the strip on of the operator side before rolling and based thereon controlling the roll gap actuator on the operator side, and estimating a desired roll gap on the drive side of the mill based on the computed relative reduction of the strip and the thickness of the strip on the drive side before rolling and based thereon controlling the roll gap actuator on the drive side. ### Claim 9 (depends on 1) A computer program product directly loadable into the internal memory of a computer, comprising software performing the steps of the method recited in claim 1. ### Claim 10 (depends on 1) A computer readable medium, having a program recorded thereon, where the program is to make a computer perform the steps of the method recited in claim 1, when said program is run on the computer. ### Claim 11 (depends on 1) The method according to claim 1, wherein thickness correction is on the order of microns. ### Claim 12 A method for controlling a roll gap when rolling a strip (1) having lateral edges in a rolling mill and including at least two rolls (3a-b,4a-b), and at least two roll gap actuators (6,7) positioned to be adjacent the respective lateral edges of the strip (10) and which independently control size of the roll gap, wherein the method comprises: receiving information on amount of wedge shape (H, POSactOS, POSactDS) in strip thickness profile across strip width, and based thereon, and controlling said actuators such that relative reduction of the strip at both edges of the strip (1) is substantially identical, and said information on the amount of wedge shape in the strip thickness profile includes actual positions (POSactOS, POSactDS) of said roll gap actuators. ### Claim 13 A device for controlling a roll gap when rolling a strip (1) having lateral edges in a rolling mill having two sides and including at least two rolls (3a-b,4a-b), and at least two roll gap actuators (6,7) positioned to be adjacent the respective lateral edges of the strip (1) and which independently control size of the roll gap, wherein the device is adapted to receive information on amount of wedge shape (H, POSactOS, POSactDS) in strip thickness profile across strip width, determine relative reduction of the strip (1) by the formulas Δh/H or Δh/h, where Δh=H−h, with H denoting thickness of the strip (1) before entering the roll gap and h denoting thickness of the strip after passing through the roll gap, and control said actuators (6,7), based on said information on the amount of wedge shape in the strip thickness profile, such that relative reduction (Ah) of the strip (1) at both edges of the strip (1) is substantially identical. ### Claim 14 (depends on 13) The device according to claim 13, wherein said information on the amount of wedge shape includes information on the thickness profile (H) across the strip width of the strip to be rolled. ### Claim 15 (depends on 13) The device according to claim 13, wherein said rolling mill further includes a thickness control system, which calculates a thickness correction for the roll gap based on a desired strip thickness, and the device is adapted to receive information on the thickness correction, and control said actuators, based on the thickness correction and the amount of wedge shape in the strip thickness, such that the relative thickness corrections at both edges of the strip (1) are substantially identical. ### Claim 16 (depends on 15) The device according to claim 15, wherein said roll gap actuators independently control the size of the roll gap on an operator side of the mill adjacent one of the lateral edges of the strip (1) and on a drive side of the mill adjacent the other lateral edge of the strip (1), and the device is adapted to compute a thickness correction to be applied to the roll gap actuator on the operator side and a thickness correction to be applied to the roll gap actuator on the drive side based on the thickness correction and the amount of wedge shape in the strip thickness. ### Claim 17 (depends on 16) The device according to claim 16, wherein desired size dOS of the roll gap on the operator side is calculated based on the following equation: d OS = Δ ⁢ ⁢ hc Hc * H OS , where HOS is the strip thickness on the operator side before rolling, Hc is the strip thickness at the center of the strip before rolling, and Δhc is the change in thickness at the center of the strip after rolling, and desired size dDS of the roll gap on the drive side is calculated based on the following equation: d DS = Δ ⁢ ⁢ hc Hc * H DS , where HDS is the strip thickness on the drive side before rolling. ### Claim 18 (depends on 16) The device according to claim 16, wherein the thickness corrections are determined by the formula POSaddOS=2POSadd−POSaddDS. ### Claim 19 (depends on 13) The device according to claim 13, wherein the device is adapted to receive information on the thickness of the strip before rolling the strip at least at two points across the width of the strip and after rolling the strip at least at one point across the width of the strip, compute a relative reduction of the strip based on the thickness of the strip before and after rolling, and control said actuators based on the computed relative reduction of the strip and said information on the thickness of the strip before rolling the strip at least at two points. ### Claim 20 (depends on 19) The device according to claim 19, wherein said roll gap actuators independently control the size of the roll gap on an operator side of the mill adjacent of the lateral edges of the strip (1) and on a drive side of the mill adjacent the other later edge of the strip (1), and the device is adapted to estimate a desired roll gap on the operator side of the mill based on the computed relative reduction of the strip and the thickness of the strip on the operator side before rolling and based thereon controlling the roll gap actuator on the operator side, and estimating a desired roll gap on the drive side of the mill based on the computed relative reduction of the strip and the thickness of the strip on the drive side before rolling and based thereon controlling the actuator on the drive side. ### Claim 21 (depends on 13) The device according to claim 13, wherein thickness correction is on the order of microns. ### Claim 22 A device for controlling a roll gap when rolling a strip (1) having two sides in a rolling mill and including at least two rolls (3a-b,4a-b), and at least two roll gap actuators (6,7) positioned to be adjacent the respective lateral edges of the strip (1) and which independently control size of the roll gap, wherein the device is adapted to receive information on amount of wedge shape (H, POSactOS, POSactDS) in strip, thickness profile across strip width, and control said actuators, based on said information on the amount of wedge shape in the strip thickness profile, such that relative reduction of the strip (1) at both edges of the strip (1) is substantially identical, and said information on the amount of wedge shape includes actual positions (POSactOS, POSactDS) of said roll gap actuators. ### Claim 23 A device for controlling a roll gap when rolling a strip (1) having lateral edges in a rolling mill, comprising two main rolls (3a, 3b) positioned to apply pressure to the strip (1), and two support rolls (4a, 4b) each positioned against a respective one of said main rolls (3a, 3b) on a side of the respective main roll (3a, 3b) opposite the strip (1), at least two roll gap actuators (6,7) arranged to contact one (4a) of said two support rolls (4a, 4b) adjacent the respective lateral edges of the strip (1) and independently control size of the roll gap, wherein the device is adapted to receive information on amount of wedge shape (H, POSactOS, POSactDS) in strip thickness profile across strip width, and control said actuators (6, 7), based on said information on the amount of wedge shape in the strip thickness profile, such that relative reduction of the strip at both edges of the strip (1) is substantially identical.