I. Product Introduction

Japan NMT rolling mill bearings are specifically designed for steel metallurgical and non-ferrous metal rolling equipment, covering four-row tapered roller bearings, four-row cylindrical roller bearings, Sendzimir mill bearings and other series,适配 the different operating condition requirements of hot rolling, cold rolling, continuous casting and various non-ferrous metal rolling production lines.

 

Four-Row Tapered Roller Bearings: Feature precision-matched inner and outer ring assemblies to ensure uniform load distribution across all four rows of raceways. Rollers are manufactured with logarithmic crowning to eliminate edge stress concentration. This bearing type can simultaneously withstand radial loads and bidirectional axial loads, suitable for work rolls and backup rolls in hot and cold rolling mills.

 

Four-Row Cylindrical Roller Bearings: Four rows of rollers are arranged in parallel, with radial load capacity 3.5 to 4 times that of single-row bearings. Cylindrical rollers and raceways form line contact, providing high radial load capacity suitable for heavy loads and impact loads. Cages are manufactured as solid brass structures or pin-type welded structures, 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. Sealed rolling bearings effectively prevent liquid and contaminant ingress, reducing requirements for working environment cleanliness while also reducing grease consumption.

 

II. Core Product Advantages

Manufacturing Precision: Manufacturing precision is the core competency of the NMT brand. Production lines utilize fully closed-loop controlled ultra-precision grinding systems equipped with nanometer-resolution in-process measurement devices that monitor and correct machining parameters in real time, ensuring bearing ring raceway geometry accuracy reaches sub-micron levels. Raceway roundness and waviness are协同 controlled within extremely tight tolerances.

 

High-Purity Materials: Bearing rings and rolling elements are manufactured from high-purity bearing steel 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 the core maintains toughness. This “hard-surface, tough-core” structure enables bearings to resist indentation and spalling on the surface while the core absorbs impact energy under impact loads. Steel materials经过 special thermal stabilization treatment, with retained austenite content controlled to extremely low levels, maintaining dimensional stability through repeated thermal cycling.

 

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.

 

Extended Life and High Reliability: Through improved material purity, precision heat treatment and optimized design, bearing wear resistance is significantly enhanced. Long-term stable operation can be achieved under proper installation and standardized maintenance.

 

Precision Matching: NMT emphasizes the ultimate pursuit of micro-level contact precision between rolling elements and raceways, with the fit condition naturally presented after precision matching reflecting NMT's strict management of “clearance”. This precision fit relationship runs throughout the entire process of product design, manufacturing and assembly.

 

III. Typical Application Scenarios

Hot Roughing and Finishing Mills——Work roll and backup roll bearings. Withstand high-temperature radiation (housing temperatures up to 150-250°C), thousands of tons of rolling force and impact during billet biting. Hot rolling mill speeds are relatively lower, but loads are greater.

 

Cold Rolling Mills——Work roll and backup roll bearings. Require high rotational accuracy and rigidity to meet micron-level strip thickness tolerance control. Cold rolling mill speeds are notably higher than hot rolling, with more strictly controlled thickness tolerances and higher surface quality requirements. Cold rolling mills typically require long-duration operation, particularly with continuous rolling designs where steel coils are joined end-to-end as they enter the mill.

 

Continuous Casters——Segment bearings. Low-speed, heavy-load, continuous water spray environment. Continuous caster bearings must withstand high temperatures, cooling water and continuous dust attack.

 

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.

 

Levelers and Skin Pass Mills——Levelling roll bearings.

 

IV. Quality Assurance

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 unevenness 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. Through precise control of heat treatment processes, an ideal “rigid yet tough” condition is achieved.

 

Precision Machining: Critical processes are completed in temperature-controlled clean workshops. Production lines utilize fully closed-loop controlled ultra-precision grinding systems equipped with nanometer-resolution in-process measurement devices that monitor and correct machining parameters in real time. 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出厂 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.

 

V. Product Range

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适配 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适配 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适配 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.

 

VI. Brand Strength

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

 

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

 

Manufacturing Capability: Production lines utilize fully closed-loop controlled ultra-precision grinding systems equipped with nanometer-resolution in-process measurement devices that monitor and correct machining parameters in real time. Critical processes are completed in temperature-controlled clean environments, with product precision grades meeting P5, P4 and higher requirements.

 

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. In the field of precision motion, NMT's strict management of “clearance” runs throughout the entire process of product design, manufacturing and assembly.

 

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.

 

VII. Global Collaboration

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

 

Service Reach: Products are适配 for 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. Based on extensive experience in rolling mill bearing design, manufacturing and field application, combined with on-site bearing condition assessment and physical/chemical failure analysis, NMT helps users accurately identify bearing application issues and propose corresponding improvement measures.

 

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 and reducing bearing cost per ton of steel.