Method for operating an annealing furnace

• US 11,230,749 B2
• Filed: 06/05/2018
• Issued: 01/25/2022
• Est. Priority Date: 06/20/2017
• Status: Active Grant

• Current Assignee: SMS Holding GmbH (Bernhard-Weiss-Stiftung)
• Original Assignee: SMS Holding GmbH (Bernhard-Weiss-Stiftung)
• Inventors: Daube, Thomas, Jaenecke, Markus, Kummel, Lutz, Sommers, Ulrich, Lhoest, Alexandre
• Primary Examiner(s): Kastler, Scott R
• Application Number:
  US16/624,582
• Publication Number:
  US 20200131599A1
• Time in Patent Office: 1,330 Days
• CPC Class Codes: B21B 2037/002 Mass flow control
• CPC Class Codes: B21B 2261/20 Temperature
• CPC Class Codes: B21B 37/74 Temperature control, e.g. by cooling or heating the rolls or the product B21B37/32, B21B37/44 take precedence
• CPC Class Codes: C21D 11/00 Process control or regulation for heat treatments
• CPC Class Codes: C21D 9/56 Continuous furnaces for strip or wire
• CPC Class Codes: C21D 9/561 with a controlled atmosphere or vacuum
• CPC Class Codes: C21D 9/562 Details
• CPC Class Codes: F27D 2019/0003 Monitoring the temperature or a characteristic of the charge and using it as a controlling value
• CPC Class Codes: F27D 2019/0059 Regulation involving the control of the conveyor movement, e.g. speed or sequences
• CPC Class Codes: F27D 21/0014 Devices for monitoring temperature

Abstract

A method for operating an annealing furnace to anneal a metal strip provides that, initially, at least one target material property (MP_Target) is specified for a point or a section of the metal strip after passing through the annealing furnace. In addition, information (E) on the metal strip is provided before or in the annealing furnace. A calculation of a target temperature distribution (T_Target) and/or a target speed (V_Target) of the metal strip in the annealing furnace is then carried out with the assistance of a computer-aided model as a function of the target material properties and the specified information. The target temperature distribution and/or target speed calculated in this manner is/are subsequently set in the annealing furnace in order to transfer the material property of the metal strip behind the annealing furnace to the desired target material property MP_Target.

Claims

1. A method for operating an annealing furnace (200) for annealing a metal strip, comprising the following steps:

selecting a desired target material property (MP_Target), to be assumed by a point or section of the metal strip (100) after passing through the annealing furnace (200), the target material property (MP_Target) being one of a yield strength, a tensile strength, an elongation at break and a uniform elongation;

providing information (E) relating to the metal strip in front of or in the annealing furnace (200);

calculating a target temperature distribution (T_Target) and/or a target speed (V_Target) of the metal strip (100) in the annealing furnace (200) by a computer-aided model (220) as a function of the desired target material property (MP_Target) and the information (E) relating to the metal strip;

setting the target temperature distribution (T_Target) and/or the target speed (V_Target) of the metal strip (100) in the annealing furnace (200) by a furnace control system (230) as a control element;

measuring an actual material property (MP_Actual) of the metal strip (100) after passing through the annealing furnace (200);

calculating a comparative temperature distribution (T_Comp) and/or a comparative speed (V_Comp) of the metal strip (100) in the annealing furnace (200) with by the computer-aided model (220) as a function of the measured actual material property (MP_Actual) of the metal strip (100) after passing through the annealing furnace (200) and the information (E) relating to the metal strip in front of or in the annealing furnace (200); and

adjusting the temperature distribution and/or the speed of the metal strip (100) in the annealing furnace (200) to the comparative temperature distribution (T_Comp) and/or the comparative speed (V_Comp) through adapting of the computer-aided model;

wherein the adapting of the computer-aided model takes place only after the passing of at least the entire metal strip through the annealing furnace (200), and

wherein the adapting of the computer-aided model comprises the sub-steps of

measuring an actual temperature distribution (T_Actual) and/or an actual speed (V_Actual) of the metal strip (100) in the annealing furnace (200),

comparing the actual temperature distribution (T_Actual) with the calculated comparative temperature distribution (T_Comp) and determining a temperature deviation (Δ

T); and

/or

comparing the actual speed (V_Actual) of the metal strip (100) in the annealing furnace (200) with the comparative speed (V_Comp) and determining a speed deviation (Δ

V);

calculating at least one adaptation value (a) for adjustment of the computer-aided model (220) based on the temperature deviation (Δ

T) and/or the speed deviation (Δ

V);

adapting the computer-aided model (220) based on the adaptation value (a); and

recalculating the target temperature distribution (T_Target) and/or the target speed (V_Target) of a new metal strip (100) by the adapted computer-aided model (220), and

wherein the information (E) relating to the metal strip (100) before or in the annealing furnace (200) is selected from the group consisting of

a tensile strength and/or a yield strength before a continuous galvanizing line (CGL), before a continuous annealing line (CAL), in a pickling line, or before a reel,

a reel temperature,

a final rolling temperature of the metal strip upon exiting a finishing roll train,

an input temperature of a slab from which the metal strip is produced, at the input of the finishing roll train,

a strip speed of the metal strip upon exiting a last stand of the finishing roll train,

a rolling force in a skin pass mill,

rolling forces during cold rolling,

rolling forces during hot rolling,

an input temperature of the slab into a roughing stand in front of the finishing roll train,

a cold rolling grade,

a composition of a material of the metal strip,

a carbon content of the metal strip; and

a straightening force at a flattener in front of the CGL/CAL.

2. The method according to claim 1, wherein measuring the actual material property (MP_Actual) of the metal strip (100) after passing through the annealing furnace (200) is performed at the point or section of the metal strip for which the desired target material property is specified.

3. The method according to claim 1, wherein the adaptation of the computer-aided model takes place only after the passing of a plurality of metal strips through the annealing furnace (200).

4. The method according to claim 1, wherein calculating the target temperature distribution and/or the target speed of the metal strip takes place as long as the at least one point or section of the metal strip to which the desired target material property (MP_Target) of the metal strip refers is still located before or in the annealing furnace (200).

5. The method according to claim 1, wherein the computer-aided model (220) uses an experience database, a statistical model, or stored annealing curves when calculating the target temperature distribution (T_Target) and/or the target speed (V_Target).

6. The method according to claim 1, wherein the actual material property of the metal strip is measured directly online or on a sample taken from the metal strip after the metal strip (100) has passed through the annealing furnace.

7. The method according to claim 1, further comprising

repeating the steps according to claim 1 with the adapted computer-aided model when annealing a future metal strip (100).