Product Description
Manufactured in our specialized metallurgical casting and machining facilities in Jingjiang, our Hearth Roll is a high-temperature centrifugally cast furnace roll engineered to support and convey steel strip through continuous annealing lines (CAL), continuous galvanizing lines (CGL), and roller-hearth heat-treatment furnaces. Drawing upon 26 years of high-alloy casting expertise and supplying leading steel groups like Baowu, POSCO, and JFE, we produce each Hearth Roll with centrifugally cast heat-resistant alloy barrels, forged journals, and dynamic balancing conforming to ISO 1940 Grade G6.3. Finished with specialized thermal-spray ceramic coatings (HVOF or detonation gun) exceeding 60 HRC, this premium Hearth Roll resists high-temperature pickup, nodular buildup, and mechanical wear under furnace temperatures up to 1,100°C, providing steelmakers with an essential furnace roll engineered to prevent strip scratching during continuous thermal processing.
Applications
Continuous Galvanizing Lines (CGL): Conveying strip through direct-fired heating, radiant tube soaking, and cooling sections.
Continuous Annealing Lines (CAL): Operating inside vertical furnace towers to support cold-rolled automotive steel sheet.
Roller Hearth Heat Treatment Furnaces: Transporting heavy plates, seamless pipes, and bar stock through normalizing, quenching, and tempering zones.
Silicon Steel Heat-Treatment Lines: Conveying grain-oriented electrical steel strips under hydrogen/nitrogen atmospheres.
Technical Specifications
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Design Standards |
Metallurgical Furnace Roller Standards, ISO 9001, ASTM A608, DIN 17465 |
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Manufacturing Process |
Horizontal centrifugal casting for roll barrels; static casting/forging for roll necks; automated narrow-gap welding |
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Roll Barrel Alloys |
ZG45Cr28Ni48W5, ZG40Cr25Ni20Si2, ZG30Cr26Ni12, GX40CrNiSi25-20, Supertherm |
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Roll Dimensions |
Outer diameter (OD) from 150 mm to 1,500 mm; Barrel lengths up to 3,000 mm; Overall lengths up to 5,500 mm |
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Design Service Temperature |
800°C to 1,150°C |
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Surface Roughness |
Ground and polished to Ra 0.8 µm – Ra 0.4 µm |
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Ceramic Coating Types |
Detonation gun or HVOF-sprayed ZrO2, Cr3C2-NiCr, or Al2O3-TiO2 coatings |
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Coating Surface Hardness |
≥ 60 HRC (High-temperature anti-pickup and wear-resistant) |
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Dynamic Balancing |
ISO 1940 Grade G6.3 / G2.5 at furnace operating speed |
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Barrel Profiles |
Flat cylindrical, single-taper, or dual-taper crown profiles |
Customization Capabilities
Coating Formulations for Anti-Pickup: Formulating specialized ceramic and cermet coatings to prevent iron/zinc nodule accretion (nodulation) in galvanizing furnaces, protecting automotive-exposed sheet surfaces.
Thermal Crown Profile Machining: Precision-grinding dual-cone or parabolic crown geometries to counteract roll thermal expansion and maintain strip tracking.
Internal Water-Cooled Shaft Journals: Integrated cooling water chambers and rotary siphon pipes in roll necks to protect external roller bearings.
Fine-Grained Microstructural Control: Controlling centrifugal mold spinning speeds to produce equiaxed outer surface crystals and uniform radial density.
Zero MOQ Restriction: Custom manufactured for turnaround roll-campaign replacements or complete multi-roll furnace installations.
Quality Control
Manufacturing Accreditations: ISO 9001:2015, ISO 14001:2015, and ISO 3834-2 welding quality management.
Full Process QR Code Traceability: Every cast barrel, forged trunnion, and coating batch carries an individual QR code linked to certified chemical analyses and inspection records.
Non-Destructive Testing: 100% Ultrasonic Testing (UT) on welded journal joints; Liquid Penetrant Testing (PT) across the full roll barrel face before and after coating.
Coating Adhesion & Roughness Testing: Metallographic bond inspection, coating thickness verification, and profilometer roughness mapping.
Heavy Ocean Packaging: Protective felt wrapping, corrosion-resistant VCI covers, dynamic balancing mark preservation, and crated in rigid wooden boxes.
FAQ
Q: Why is ceramic coating critical for hearth rolls in continuous galvanizing furnaces?
A: At temperatures above 800°C, bare alloy rolls can chemically react with strip scale and zinc vapor, creating hard nodules ("pickup") that indent and scratch strip surfaces. Our thermal-sprayed ceramic coatings provide a chemically inert barrier with hardness over 60 HRC, preventing nodulation and preserving strip surface quality.
Q: What is the typical lead time for a set of coated hearth rolls?
A: Centrifugal casting, machining, welding, and thermal-spray coating typically require 3 to 4 months from drawing sign-off to final inspection.
Q: What warranty coverage do you provide?
A: We provide an 18-month warranty from site arrival or 12 months from commercial operation (whichever comes first).
Q: What payment terms are accepted?
A: Standard commercial terms are 30% advance deposit, 40% manufacturing milestone payment, and 30% balance prior to export shipment, payable in USD, EUR, or RMB.
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