Classifications

• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D11/00—Process control or regulation for heat treatments
  • C21D11/005—Process control or regulation for heat treatments for cooling
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21B—ROLLING OF METAL
  • B21B37/00—Control devices or methods specially adapted for metal-rolling mills or the work produced thereby
  • B21B37/74—Temperature control, e.g. by cooling or heating the rolls or the product
  • B21B37/76—Cooling control on the run-out table
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
  • C21D9/52—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for wires; for strips ; for rods of unlimited length
  • C21D9/54—Furnaces for treating strips or wire
  • C21D9/56—Continuous furnaces for strip or wire
  • C21D9/573—Continuous furnaces for strip or wire with cooling
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21B—ROLLING OF METAL
  • B21B2261/00—Product parameters
  • B21B2261/20—Temperature
  • B21B2261/21—Temperature profile

Definitions

• the invention relates to a method for controlling and / or regulating the cooling section of a hot strip mill for rolling metal strip, in which the structural properties of the rolled metal strip, in particular a steel strip, are set by the cooling.
• the invention also relates to the associated device for fürfuh ⁇ out the method.
• slabs are rolled into strip in a hot strip mill. After rolling, the sheet goes through a cooling section.
• the cooling section of the hot strip mill is used to adjust the structural properties of the rolled steel strip.
• the structural properties of the strips produced have so far been derived predominantly from the reel temperature, which is kept constant at a predetermined setpoint value by the automation of the cow section.
• New materials such as multi-phase steels, TRIP steels or the like, require a precisely defined heat treatment, i.e. the specification and monitoring of a temperature profile from the last rolling stand to the reel.
• Direction can be detected.
• a calculation is carried out using the "finite element" method.
• the control and / or regulation is no longer tied to fixed switching locations; there are in fact any time any valves for coolant supply ⁇ actuatable. So that compliance with the specified cooling along the cooling section can be checked by the control and / or regulation, according to the invention, the model is included in real time with the band of the cooling section. This provides the required strip temperatures on the cooling section and is constantly corrected by measured temperature values.
• the method according to the invention thus allows a flexible specification of the heat treatment for modern steels. This takes account of practical requirements.
• each of which contains a cooling section which can be acted upon with cooling agents over their entire length by means of individually adjustable valves, there are means for specifying cooling curves for the individual strip points of the metal strip.
• Figure 1 shows the structure of a downstream of the rolling mill
• FIG. 2 a three-dimensional temperature-time / band length diagram
• FIG. 3 shows the structure diagram of the control / regulation confining ⁇ Lich model correction for the Kuhlpiece according to Figure 1 and Figure 4 in detail the calculation of the model correction of FIG. 3
• FIG. 1 The cooling of metal strip as part of the hot rolling technology and the function of the cooling section there is illustrated in FIG. 1.
• hot rolling steel so-called slabs with an initial thickness of approx. 200 mm are rolled into a strip of 1.5 to 20 mm.
• the processing temperature is 800 to 1200 ° C.
• the end of the process involves cooling the strip with water from a cooling section to 300 to 800 ° C.
• the last rolling stand of a hot strip mill is designated by 1 in FIG.
• the mill stand 1 is followed by a finishing station measuring station 2, after cooling a reel measuring station 3, at each of which the temperature of the strip is measured, and then an underfloor reel 4 for reeling the metal strip into a coil.
• the cooling section 10, generally referred to in the present context as a system, is located between the finished street measuring station 2 and the reel measuring station 3.
• a rolled hot strip made of steel is designated 100 in FIG. It runs through the cooling section 10 and is from both sides via valves with a cooling medium, in particular Water, chilled.
• a cooling medium in particular Water, chilled.
• Individual valves can be combined into groups, for example the valve groups 11, 1Y, ..., 12, 12 ⁇ ..., 13, 13 ⁇ ... and 14, 14 ⁇ ... are shown.
• the cooling of the strip 100 which is to be recorded by control technology, is usually based on a one-dimensional mstationary heat conduction equation.
• the mathematical description is based on an insulated rod which only exchanges heat with the surroundings at the beginning and end - corresponding to the top and bottom of the strip.
• the band 100 can be described with individual band points, which are heated in the rod. This is known, for which reference is made to the relevant specialist literature.
• no temperatures can be measured in the cooling section 10.
• the temperature is measured at measuring station 2 in front of the cooling section and in particular at reel measuring station 3.
• the heat exchange in band 100 is taken into account via the mathematical model in accordance with the above requirements.
• a model of the cooling section is thus created, which is designated 15 in FIG. If the temperatures are available at any point via the model 18, regulation to the specified cooling profile can be implemented.
• the Temperaturprofll for the tape after a certain cooling time point i to t ⁇ a predetermined Tempe ⁇ temperature Ti, in particular coiling temperature T h have. Ent ⁇ speaking specifications are also available for the remaining strip points. If all the specified reel temperatures of the individual strip points are connected, the curve 400 shown in FIG. 2e is obtained. This curve 400 can be used, for example, to ensure that process steps such as grasping the strip on the reel are taken into account with the smallest possible structural changes ,
• curve 500 represents the cooling profile over the cooling section length. This cooling curve is also shown in FIG. 1 unit 30. It is essential that curve 500 is automatically dynamically adapted in the event of disruptions in the production process, for example at variable belt speed, in accordance with the technical teaching specified. As a result, in contrast to the prior art, such disturbances remain without any effects on the predetermined cooling process of each band point.
• cooling curves 300, 310, 311, 312 etc. are specified for each band point. For example, for the first point a cooling curve is specified with an initially steep drop and then a flatter drop, while in the middle cooling curves with an almost constant temperature gradient. The described profile 400 is thus achieved overall.
• the Pro ⁇ fil can be set so that the greatest possible extent constant Gefuge ⁇ properties are present on the finished band.
• the structural properties determine the mechanical properties and thus the quality of steel strip in particular, the desired material properties can be achieved through targeted structural changes.
• the described method results in an increased potential in the production of finished strip.
• the cooling section is designated as the actual system with 10. 1 is printed out here by a so-called real-time model 20, by means of which the temperatures T_ at the individual band points I of the band 100 are determined.
• the calculated coiling temperature T H which is subject to an error, is compared to the measured on the reel 3 temperature- temperature T H and the resulting failure of a unit 25 is supplied to the model correction.
• the latter unit 25 is also supplied with the entire cooling process 5 calculated by the real-time model 20.
• the unit 25 uses this data to determine a correction of the cooling process, which is applied to the calculated cooling process.
• the corrected cooling curve determined in this way is compared with the target cooling and the resulting control deviation with the controller 30 fed. From this and by means of the amplification factors determined by the unit 25, the valve positions are generated as process control signals, which are both implemented on the system and also fed back to the real-time model 20 as information.
• the controller 30 can be operated with a predetermined algorithm on the basis of the entered control deviation and the further values. Such algorithms are specified in software and allow the control of any pattern of valves.
• each of the valves 11, 11 ⁇ ..., 12, 12 ⁇ ..., 13, 13 ⁇ , ..., 14, 14 ⁇ ... can be activated by any combination of the controller at the same time.
• the cooling along the metal strip is considered in detail on the basis of the enthalpy and the temperature profile dependence on the enthalpy.
• the calculation of the model correction for the controller is illustrated in detail in FIG. 4: the enthalpies e and the temperatures T m are determined as a function of the enthalpy e.
• the real-time model 20 supplies a calculated enthalpy value e, from which the value T (e) is formed in a unit 21. From this, the temperature values T for any band points can be calculated. Specifically, the calculated temperature value T H for the reel temperature is compared with the measured reel temperature T H , which results in a value ⁇ T ⁇ .
• enthalpy signals are equally fed to a unit 22, which is the partial derivative de the enthalpy according to the heat conduction coefficient is forming.
• the heat conduction coefficient represents a correction factor to a certain extent.
• the valve positions of the system continue to enter both ends 20 and 22.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Materials Engineering (AREA)
• Thermal Sciences (AREA)
• Crystallography & Structural Chemistry (AREA)
• Physics & Mathematics (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Control Of Metal Rolling (AREA)
• Control Of Heat Treatment Processes (AREA)
• Heat Treatment Of Strip Materials And Filament Materials (AREA)
• Metal Rolling (AREA)
• Heat Treatments In General, Especially Conveying And Cooling (AREA)

Applications Claiming Priority (3)

Publications (2)

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• 1999
  • 1999-12-27 DE DE19963186A patent/DE19963186B4/de not_active Expired - Lifetime
• 2000
  • 2000-12-15 ES ES00991077T patent/ES2217028T3/es not_active Expired - Lifetime
  • 2000-12-15 EP EP00991077A patent/EP1244816B1/fr not_active Expired - Lifetime
  • 2000-12-15 WO PCT/DE2000/004489 patent/WO2001047648A2/fr active Search and Examination
  • 2000-12-15 AT AT00991077T patent/ATE261498T1/de active
  • 2000-12-15 CN CNB00818593XA patent/CN100402675C/zh not_active Expired - Lifetime
  • 2000-12-15 DE DE50005630T patent/DE50005630D1/de not_active Expired - Lifetime
  • 2000-12-15 PT PT00991077T patent/PT1244816E/pt unknown
  • 2000-12-15 US US10/169,183 patent/US6866729B2/en not_active Expired - Lifetime

Non-Patent Citations (1)

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