Extending Sink Pot Roll Life in Continuous Galvanizing Lines

     Hot-Dip Galvanizing Lines (HDGL), also referred to as Continuous Galvanizing Lines (CGL), play a critical role in producing corrosion-resistant steel for industries such as automotive, construction, and home appliances. By applying a protective zinc coating to steel strip, these lines significantly extend product lifespan while maintaining surface quality and performance.

     Achieving consistent coating quality and operational reliability depends on a tightly controlled, continuous process that includes cleaning, annealing, galvanizing, and tempering. At the center of this process are components operating inside the zinc pot which directly influence strip quality, line stability, and overall equipment longevity.

 The Challenge Inside the Zinc Bath

     Few components in a galvanizing line operate under more demanding conditions than sink and stabilizing rolls. Submerged continuously in molten zinc or zinc-aluminum alloys at temperatures approaching 450°C (842°F), these rolls are exposed to a highly aggressive combination of thermal load, chemical reactivity, abrasion, and corrosion.

     At elevated temperatures, zinc reacts readily with iron particles from both the steel strip and the roll surface. This interaction leads to iron dissolution and the formation of zinc-iron intermetallic dross, which presents multiple operational challenges:

• Dross adheres to roll surfaces, causing surface defects and negatively impacting strip quality
• Increased friction leads to higher abrasive wear between the strip and roll
• Accelerated roll degradation shortens campaign duration
• More frequent roll exchanges increase downtime and maintenance costs

Combined with the corrosive nature of molten zinc baths, these factors place extreme demands on sink pot roll materials, surface treatments, and maintenance strategies.

Introducing ZincGen: A Purpose-Engineered Coating Solution

To address these challenges, Hannecard has developed ZincGen, a specialized coating solution engineered specifically for CGL sink pot applications.

ZincGen is designed to combat metallic corrosion at the roll–molten bath interface by significantly reducing the interaction between zinc and iron particles. By minimizing this reaction, ZincGen delivers several critical benefits:

• Reduced iron dissolution from the roll surface
• Limited formation and adhesion of zinc-iron dross
• A smoother, more stable roll surface throughout extended campaigns

The result is consistent strip quality, even under aggressive galvanizing conditions, while improving overall line reliability.

Performance Benefits in CGL Operations

ZincGen offers measurable improvements compared to traditional non-coated sink rolls:

• Extended service life: ZincGen-coated sink rolls achieve a longer service life, significantly extending campaign duration.
• Reduced downtime: Longer-lasting rolls mean fewer roll changes and improved line availability.
• Improved wear resistance: The coating resists abrasive wear caused by continuous strip contact in molten zinc environments.
• Lower total cost of ownership: ZincGen-coated rolls can be re-coated multiple times, maximizing the usable life of core components and reducing capital expenditure.
• Application flexibility: ZincGen can also be applied to sink roll arms and sleeves, extending protection across additional critical components within the zinc pot.

Comprehensive Roller Solutions for HDGL and CGL Applications

     Beyond advanced coating technologies, Hannecard provides comprehensive, turnkey solutions for zinc pot rolls, stabilizer rolls, and associated components. These services are designed to ensure long-term equipment performance, reliability, and cost efficiency.

Hannecard’s turnkey services include:

• Thorough inspections: Detailed assessments to identify wear, damage, or inefficiencies
• Acid pickling: Cleaning of rolls, arms, scraper blades, and bearing housings for optimal performance
• Mechanical repairs: Expert restoration of components to original specifications
• Disassembly and assembly: Precision handling during maintenance and refurbishment
• Specialized coatings: High-quality coatings for arms and ingot hooks
• Journal repairs: Dimensional restoration to extend journal lifespan
• In-house grooving: Micro- and macro-grooving tailored to application requirements
• Advanced seal treatments: Multiple options, including furnacing, for enhanced durability
• Journal re-stubbing & shaft repairs: Expert solutions for damaged or worn shafts

By combining advanced coatings like ZincGen with full lifecycle roller services, Hannecard helps galvanizing lines operate efficiently and reliably for years to come.

Designed for Demanding Galvanizing Environments

     ZincGen is part of Hannecard’s advanced thermal spray coating portfolio, developed through a deep understanding of metallurgical interactions, high-temperature corrosion mechanisms, and real-world HDGL and CGL operating conditions. The coating is engineered not only for durability, but also for process stability, helping galvanizing lines maintain quality and throughput over extended production runs.

Technical Expertise You Can Rely On

     Selecting the right coating and refurbishment strategy requires more than a standard specification—it requires technical collaboration. Hannecard supports ZincGen with in-house expertise, including access to a Key Materials Engineer and Thermal Spray Coating Specialist.

     For operations evaluating coating performance, campaign optimization, or alternative technologies such as thermal spray or cold spray solutions, Hannecard’s engineering team works directly with customers to assess operating conditions and recommend the most effective approach.

Learn More

     To discuss your specific Hot-Dip or Continuous Galvanizing Line sink pot roll requirements, or to learn how ZincGen and Hannecard’s turnkey services can reduce downtime and extend equipment life, contact Hannecard. Our technical team is ready to support your coating, repair, and materials engineering needs.