一、Product Introduction

Japan NMT steel and metallurgical rolling mill bearings are precision bearing product series designed specifically for steel and non-ferrous metal rolling equipment. Products cover hot rolling, cold rolling, continuous casting and various non-ferrous metal rolling production lines,适配 different mill types and operating conditions.

 

Four-Row Tapered Roller Bearings: Applied to work rolls and backup rolls in hot and cold rolling mills. Bearings feature precision-matched inner and outer ring assemblies, ensuring uniform load distribution across all four rows of raceways. Rollers are manufactured with logarithmic crowning to eliminate edge stress concentration and ensure uniform contact stress distribution along the full roller length. Ring wall thickness is calculated to maintain geometric accuracy under heavy-load conditions. Axial clearance is precisely set according to operating temperature to compensate for thermal expansion.

 

Four-Row Cylindrical Roller Bearings: Applied to mill backup rolls and continuous caster segments, primarily withstanding radial loads. Four rows of rollers are arranged in parallel, with roller quantity four times that of single-row bearings and radial load capacity 3.5 to 4 times that of single-row bearings. Cages are manufactured as solid brass structures or pin-type welded structures (for large bearings), maintaining precise roller guidance under impact and vibration.

 

Sealing Systems: Configured with labyrinth seals, contact rubber seals and metal shields in combination according to mill operating conditions. Seal materials are selected from FKM (fluororubber) or HNBR (hydrogenated nitrile rubber), maintaining sealing performance under water spray and high-temperature environments.

 

Lubrication Adaptation: Bearings are pre-filled with specialized grease, with base oil viscosity and additive formulations matched to load, speed and temperature conditions. For bearings using oil-mist lubrication, NMT provides products with condensation nozzles.

 

二、Core Advantages

High-Purity Materials: Bearing rings and rolling elements are manufactured from high-purity bearing steel (GCr15 or M50) processed through vacuum degassing and electroslag remelting double refining, significantly reducing non-metallic inclusion content and size to extend bearing fatigue life at the material source.

 

Precision Heat Treatment: Controlled-atmosphere heat treatment and surface carburizing/induction hardening processes achieve a surface hardness of HRC60-64 on raceway surfaces while maintaining core toughness. This structure enables bearings to resist indentation and spalling on the surface while the core absorbs impact energy under impact loads.

 

Precision Crowning: Roller generatrices are manufactured with logarithmic curve crowning to eliminate edge stress concentration, ensuring uniform load distribution along the full roller length and extending contact fatigue life under heavy-load conditions.

 

Precision Manufacturing and Inspection: Products are processed through fully automatic grinding and superfinishing in temperature-controlled clean workshops, with critical dimensional tolerances strictly controlled. Raceway roundness, rolling element grading precision and other parameters are subject to precision inspection and matching.

 

Extended Life and High Reliability: Through improved material purity, precision heat treatment and optimized design, bearing design life is significantly extended, enabling long-term stable operation under proper installation and standardized maintenance.

 

Systematic Seal and Lubrication Configuration: Multi-layer sealing solutions effectively resist water, scale and dust ingress; specialized grease formulations maintain stable lubricating films under high-temperature and water spray conditions.

 

三、Typical Applications

Hot Roughing and Finishing Mills——Work roll and backup roll bearings. Withstand high-temperature radiation (housing temperatures 150-250°C), thousands of tons of rolling force and impact during billet biting. Four-row tapered roller bearings simultaneously withstanding radial and axial loads; four-row cylindrical roller bearings withstanding radial loads.

 

Cold Rolling Mills——Work roll and backup roll bearings. Require high rotational accuracy and rigidity to meet micron-level strip thickness tolerance control. High-precision four-row tapered and cylindrical roller bearings controlled to P5 or higher precision grades.

 

Continuous Casters——Segment bearings. Low-speed, heavy-load, continuous water spray environment. Four-row cylindrical roller bearings with water-resistant seals and water-resistant grease solutions enable extended operation.

 

Sendzimir 20-High Mills——Multi-row cylindrical roller bearings (backing bearings). Achieving high load capacity and high precision within compact space.

 

Pipe Mills——Piercer and sizing mill bearings.

 

Wire Rod and Bar Mills——Finishing and pre-finishing bearings.

 

Aluminum Foil and Copper Strip Mills——High-speed precision bearings.

 

Mill Main Drives——Gearbox bearings.

 

四、Quality Assurance

NMT rolling mill bearings strictly comply with ISO precision standards and metallurgical bearing manufacturing specifications. From material melting, forging, heat treatment to grinding, superfinishing and assembly, each process follows standardized quality control procedures.

 

Material Control: Bearing steel is processed through vacuum degassing and electroslag remelting double refining to ensure material purity and structural uniformity. Key chemical composition, non-metallic inclusion ratings, carbide and other parameters are controlled to high standards.

 

Heat Treatment Control: Controlled-atmosphere heat treatment equipment is used, with quenching temperature, holding time, cooling rate and other process parameters monitored throughout. Surface hardness, case depth, core hardness, metallographic structure and other parameters are batch-tested.

 

Precision Machining: Critical processes are completed in temperature-controlled clean workshops. Raceways are superfinished to achieve high surface roughness grades; rolling elements are precision-screened and graded with roundness error controlled within tight tolerances.

 

Assembly and Inspection: Inner and outer rings of four-row bearings are precision-matched, with clearance and preload set to design target values. Finished bearings undergo rotational accuracy testing, vibration testing and clearance re-measurement to ensure products meet technical specifications.

 

Traceability Management: Each bearing set is accompanied by an independent factory serial number and inspection records, with key quality data traceable.

 

五、Product Range

NMT offers the following product series for steel metallurgical rolling equipment:

 

Four-Row Tapered Roller Bearing Series: For hot and cold rolling mill work rolls and backup rolls. Can simultaneously withstand radial loads and bidirectional axial loads. Axial clearance adjustable to different mill rigidity requirements.

 

Four-Row Cylindrical Roller Bearing Series: For mill backup rolls, continuous caster segments and other equipment primarily withstanding radial loads. Available in FC, FCD and FCDP structural types to different size specifications and installation requirements.

 

Sendzimir Mill Bearing Series: Multi-row cylindrical roller bearings for compact-space high-load requirements of 20-high mills.

 

Mill Seal and Lubrication Supporting Products: Labyrinth seals, contact seals, metal shields and other sealing components, plus specialized greases different operating conditions.

 

Custom and Non-Standard Products: Custom products with non-standard sizes and special material configurations based on users' specific mill parameters and operating conditions.

 

六、Brand Strength

Japan NMT has long been dedicated to the R&D and manufacturing of precision bearings, with decades of experience in bearing materials science, precision machining and heat treatment processes.

 

Technical Expertise: NMT channels decades of accumulated superfinishing capability into bearing manufacturing, with raceway roundness and waviness  controlled. From material selection, heat treatment to precision machining and inspection, every step is continuously optimized based on long-term application data.

 

Manufacturing Capability: Production lines utilize high-precision grinding and superfinishing equipment, with critical processes completed in temperature-controlled clean environments. Critical dimensional tolerances are strictly controlled, with product precision grades meeting P5, P4 and higher requirements.

 

Application Experience: NMT bearings have accumulated extensive actual operating data across various process scenarios including hot rolling, cold rolling, continuous casting and non-ferrous metal rolling. Based on this data, NMT continuously optimizes product design and process parameters to achieve more effective matching between bearings and different operating conditions.

 

Quality Philosophy: NMT emphasizes manufacturing precision and product consistency. Rather than rapidly expanding product lines, NMT concentrates technical resources on the refinement of core products.

 

七、Global Collaboration

NMT provides rolling mill bearing products and technical solutions to steel mills, non-ferrous metal processors and metallurgical equipment manufacturers worldwide.

 

Service Reach: Products are exported to multiple countries and regions, applied in various hot rolling, cold rolling, continuous casting and non-ferrous metal rolling production lines.

 

Collaboration Model: NMT provides not only bearing products but also technical support services including selection consultation, installation guidance, operational assessment and failure analysis. Based on users' specific mill parameters and operating conditions, NMT provides precise bearing selection recommendations and installation parameter settings.

 

Technical Support: NMT can provide on-site installation guidance, maintenance training and periodic follow-up services based on user needs, assisting users in optimizing bearing configurations and maintenance strategies to extend bearing service life and reduce bearing cost per ton of steel.

 

Remanufacturing Services: NMT provides bearing remanufacturing services, removing fatigue layers from raceway surfaces through precision grinding and replacing rolling elements and cages to restore bearing performance to near-new levels, extending overall bearing service life.