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CGL - Ligne de galvanisation en continu

CGL - Ligne de galvanisation en continu
Le but de la ligne de galvanisation continue (CGL) consiste à appliquer une couche de zinc ou de zinc/aluminium à la surface de la bande d’acier pour en améliorer la résistance à la corrosion. 

Le procédé de galvanisation alliée est parfois mis en œuvre pour appliquer le revêtement par alliage dans le substrat en acier. Cette procédure requiert une surveillance précise de la température à la sortie de la section de galvanneal. 

Depuis plus de 70 ans, AMETEK Land fournit des équipements de mesure de la température fiables et de haute qualité au secteur de l’acier. Notre gamme d’instruments spécialisés comprend la bande-thermomètre de galvanneal (GST), spécialement conçue pour surveiller l’évolution rapide de l’émissivité lors du procédé de galvanneal.

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  • Frequently Asked Questions +


    Question Answer 
    What is a CGL? A CGL (Continuous Galvanizing Line) is a high-speed production line that applies a protective zinc coating to steel strip by continuously running it through cleaning, heat treatment, a molten zinc bath and finishing operations. CGLs can process strip at speeds exceeding 180 meters per minute and produce millions of tonnes of galvanized steel annually for automotive body panels, appliances, construction materials and other corrosion-critical applications.
    What does CGL stand for? CGL stands for Continuous Galvanizing Line, distinguishing it from batch hot-dip galvanizing processes. The 'continuous' aspect is fundamental—strip is welded end-to-end and processed as an uninterrupted ribbon through all stages, maximizing throughput and coating consistency. This contrasts with batch processes where individual pieces are dipped separately. Major steel producers operate dozens of CGLs globally to meet automotive and construction demand for corrosion-protected steel.
    What are the main CGL steps? A CGL follows a precise sequence: Entry (uncoiler, welder), Cleaning (alkaline cleaning, brushing, rinsing to remove oils), Annealing (heating to ~700-850°C in controlled atmosphere to prepare metallurgy), Zinc Pot (immersion in molten zinc at ~460°C), Gas Wiping (air knives control coating thickness), Cooling, Skin Pass Mill (improves surface finish and mechanical properties), Inspection (surface quality verification) and Exit (coiler). Each stage requires tight process control for quality output.
    Why is temperature control critical? Temperature is the critical control variable throughout a CGL. In the annealing section, precise heating determines steel recrystallization and formability. At the zinc pot, strip temperature affects how zinc wets and bonds to the steel surface—too cold causes poor adhesion, too hot leads to excess intermetallic growth. Deviations of even ±10°C can cause coating defects, surface quality issues and customer rejections. This is why accurate non-contact temperature measurement is essential for CGL yield and quality.
    How do pyrometers help? LAND pyrometers provide accurate strip temperature measurement at critical CGL zones. The SPOT+ GS is optimized for galvanized strip measurement after coating, while the SPOT+ measures bare strip in annealing sections. The SPOT+ MM (Meltmaster) can monitor zinc pot temperature. These instruments deliver the real-time temperature data that process engineers need to maintain coating consistency, optimize line speed and reduce scrap—helping CGL operators achieve first-time quality rates that meet demanding automotive specifications.

  • Applications +

    • Sortie du galvanneal

      Lorsque la bande quitte le bain de zinc, elle est soumise à un traitement thermique en ligne que le revêtement forme un alliage dans le substrat en acier. Le thermomètre pour bande de Galvanneal d’AMETEK Land (GST) est conçu pour mesurer ce procédé.

      Lire la suite

    • Cylindre supérieur

      Le LSP-HD 61 surveille la température sur toute la largeur de la bande à cet endroit.

      Lire la suite

  • Vidéos +

    • SPOT GS - Temperature Measurement of Galvannealed and Galvanized Strip
      AMETEK Land SPOT GS - Temperature Measurement of Galvannealed and Galvanized Strip https://youtu.be/leNO8JclWsg

      SPOT GS enables automated furnace management to provide close control of the reaction and position of the reaction zone, delivering tighter control of product quality. By maintaining control of the reaction zone, SPOT GS accommodates rapid changes of line speed and furnace power with changes of substrate or coating weight. This allows furnace optimisation; reducing heating costs, maximising throughput and avoiding excessive over-reaction and powdering or flaking of the coating during subsequent forming operations.

    • Advances in Non-Contact Temperature Measurement for Continuous Annealing and Galvanizing Lines
      Advances in Non-Contact Temperature Measurement for Continuous Annealing and Galvanizing Lines https://youtu.be/CJFGqgTUXZ0

      We introduce how advances in accurate non-contact temperature measurements for continuous annealing (CAL) and galvanizing (CGL) lines ensure required metal characteristics and surface conditions are achieved in steel production. We will then focus on the SPOT GS, an advanced non-contact infrared spot pyrometer specifically designed for continuous, highly accurate measurements of coated steel strip temperature during the galvanneal reaction.

  • Documentations +