EP0107237B1 - Verfahren für die automatische Kontrolle des Gefüges gewalzter Stahlprodukte - Google Patents

Verfahren für die automatische Kontrolle des Gefüges gewalzter Stahlprodukte Download PDF

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Publication number
EP0107237B1
EP0107237B1 EP19830201444 EP83201444A EP0107237B1 EP 0107237 B1 EP0107237 B1 EP 0107237B1 EP 19830201444 EP19830201444 EP 19830201444 EP 83201444 A EP83201444 A EP 83201444A EP 0107237 B1 EP0107237 B1 EP 0107237B1
Authority
EP
European Patent Office
Prior art keywords
temperature
cooling
section
transformation temperature
transformation
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
EP19830201444
Other languages
English (en)
French (fr)
Other versions
EP0107237A1 (de
Inventor
Stéphan Wilmotte
Marios Economopoulos
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Centre de Recherches Metallurgiques CRM ASBL
Original Assignee
Centre de Recherches Metallurgiques CRM ASBL
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from BE6/47733A external-priority patent/BE894667A/fr
Application filed by Centre de Recherches Metallurgiques CRM ASBL filed Critical Centre de Recherches Metallurgiques CRM ASBL
Publication of EP0107237A1 publication Critical patent/EP0107237A1/de
Application granted granted Critical
Publication of EP0107237B1 publication Critical patent/EP0107237B1/de
Expired legal-status Critical Current

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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
    • 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
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/54—Determining when the hardening temperature has been reached by measurement of magnetic or electrical properties

Definitions

  • the present invention relates to a process for the automatic control of the microstructure of rolled steel products, in particular but not exclusively of products subjected to forced cooling from their rolling heat.
  • rolled steel products is intended to mean particularly long products, such as wires or baires, and flat products, such as strips and sheets.
  • microstructure which forms during the allotropic transformation during the cooling of the steel is itself strongly conditioned by the law of cooling and more especially by the temperature at which the allotropic transformation takes place.
  • the aim of the present invention is to reveal a process making it possible to determine simultaneously and at any time the evolution of the temperature and of the phase transformation within a product being cooled.
  • allotropic transformation and “phase transformation” refer to the transformation of austenite into ferrite during the cooling of the product.
  • the present invention relates essentially to the determination and use of this parameter.
  • the process which is the subject of the present invention, intended to allow automatic control of the microstructure of rolled steel products, subjected to cooling from a temperature above their upper transformation point Ar 3 , is essentially characterized in that that the transformation temperature at each point of at least one section of the product is determined, in that the average transformation temperature of said section is calculated, in that this calculated value is compared with a setpoint considered ideal for the application envisaged and in that the cooling conditions are modified, so as to reduce, preferably to cancel, the difference observed between the calculated value and the temperature setpoint section transformation average.
  • the average transformation temperature of a section is defined as the average of the transformation temperatures at the different points of the product section.
  • this average transformation temperature of a section is determined using a calculation model describing the evolution of the allotropic transformation.
  • this average transformation temperature of a section is determined from measured values of various cooling parameters, in particular the thickness and speed of the product, the initial temperature at various points. of the product, the thermal properties of the steel, the cooling conditions, the length of product sprayed, that is to say the length of the cooling zone in service.
  • the comparison between the calculated value and the set value of the average transformation temperature of the section, and / or the modification of the cooling conditions are carried out automatically.
  • a particularly advantageous embodiment of the invention consists in applying the process to products leaving the last hot rolling stand.
  • the process of the invention makes it possible to modify, in particular to reduce, the size of the ferritic grains by lowering the temperature at which they are formed, which makes it possible to vary the mechanical properties of the steel.
  • the application of the process of the invention to mild steel wires (C: 0.06% - Mn: 0.4%) of 5.5 mm in diameter made it possible to raise the elastic limit of 35 N / mm 2 in lowering the average processing temperature by 50 ° C.
  • the process of the invention takes account of the influence of the thermal path and therefore of the speed of cooling on the properties of the product.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Heat Treatment Of Strip Materials And Filament Materials (AREA)
  • Control Of Heat Treatment Processes (AREA)
  • Control Of Metal Rolling (AREA)
  • Heat Treatment Of Sheet Steel (AREA)

Claims (4)

1. Verfahren zur Überwachung der Mikrostruktur von Walzstahlprodukten, die ausgehend von einer Temperatur oberhalb ihres oberen Umwandlungspunktes einem geregelten Kühlprozeß unterzogen werden, dadurch gekennzeichnet, daß die Umwandlungstgmperatur an mindestens einem Punkt mindestens eines Abschnitts des produkts bestimmt wird, daß man die mittlere Umwandlungstemperatur des genannten Abschnitts berechnet, daß man diesen rechnerisch ermittelten Wert mit einem Sollwert der genannten mittleren Umwandlungstemperatur vergleicht, daß man die Bedingungen des genannten Kühlprozesses so ändert, daß die zwischen dem rechnerisch ermittelten Wert und dem Sollwert der genannten mittleren Umwandlungstemperatur des Abschnitts festgestellte Abweichung verringert oder vorzugsweise aufgehoben wird.
2. Verfahren gemäß Anspruch 1, dadurch gekennzeichnet, daß die mittlere Umwandlungstemperatur eines Abschnitts aus den Kühlprozenparamétern errechnet wird, insbesondere aus der Ausgangstemperatur und dem Wärmeverhalten des Produkts, aus den Kühlprozeßbedingungen, wie z. B. der Kühlmitteltemperatur und -menge, sowie aus der Länge des benetzten Produkts.
3. Verfahren gemäß einem der Ansprüche 1 und 2. dadurch gekennzeichnet, daß die rechnerische Ermittlung der mittleren Umwandlungstemperatur des Abschnitts, der Vergleich dieses errechneten Werts mit dem Sollwert dieser Temperatur und/oder die Anderung der Kühlprozeßbedingungen automatisch durchgeführt werden.
4. Verfahren gemäß einem der Ansprüche 1 bis 3, dadurch gekennzeichnet, daß der genannte geregelte Kühlprozeß für die Kühlung von Produkten eingesetzt wird, die sich in der Walzhitze befinden, unmittelbar, nachdem sie das letzte Gerüst der Walzstraße verlassen haben.
EP19830201444 1982-10-11 1983-10-10 Verfahren für die automatische Kontrolle des Gefüges gewalzter Stahlprodukte Expired EP0107237B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
BE6/47733A BE894667A (fr) 1982-10-11 1982-10-11 Procede pour le controle automatique de la structure des produits en acier lamines
BE6047733 1982-10-11

Publications (2)

Publication Number Publication Date
EP0107237A1 EP0107237A1 (de) 1984-05-02
EP0107237B1 true EP0107237B1 (de) 1986-09-03

Family

ID=3874916

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19830201444 Expired EP0107237B1 (de) 1982-10-11 1983-10-10 Verfahren für die automatische Kontrolle des Gefüges gewalzter Stahlprodukte

Country Status (3)

Country Link
EP (1) EP0107237B1 (de)
JP (1) JPS5989728A (de)
DE (1) DE3365884D1 (de)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6199632A (ja) * 1984-10-19 1986-05-17 Kawasaki Steel Corp 熱延鋼板の冷却制御方法
DE68928639T2 (de) * 1989-06-16 1998-07-30 Kawasaki Steel Corp., Kobe, Hyogo Verfahren zur regelung der kühlung von stahlmaterial
CN102156144B (zh) * 2011-03-28 2013-03-20 首钢总公司 一种棒材轧后冷却特性的分析方法

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS4843837B1 (de) * 1964-02-05 1973-12-20
BE665030A (de) * 1965-06-04 1965-10-01
GB1352567A (en) * 1971-04-28 1974-05-08 Baeckerud S L Method of checking adjusting the content of crystallization nuclei in a melt
US3670558A (en) * 1971-05-28 1972-06-20 Gen Motors Corp Rapid thermal analysis method for predicting nodular iron properties
US4008604A (en) * 1976-04-07 1977-02-22 Deere & Company Determination of carbon analysis in irons
FR2391473A1 (fr) * 1977-05-18 1978-12-15 Electro Nite Procede et dispositif pour la determination de la structure metallographique de metaux ou d'alliages
DE2742576C3 (de) * 1977-09-22 1981-10-15 Keller Spezialtechnik-Pyro-Werk GmbH, 4530 Ibbenbüren Gerät zur Messung des Kohlenstoffgehalts einer Probe einer Stahl- oder Gußeisenschmelze

Also Published As

Publication number Publication date
JPS5989728A (ja) 1984-05-24
EP0107237A1 (de) 1984-05-02
DE3365884D1 (en) 1986-10-09

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