I. Product Introduction

Japan NMT rolling mill bearings are designed based on in-depth understanding of steel metallurgical rolling operating conditions. During mill operation, bearings are subjected to the combined effects of high temperature, heavy loads, impact, water spray and scale attack——extreme conditions that impose high demands on bearing materials, design and manufacturing- NMT rolling mill bearings are adapted to actual mill operating conditions at every stage from material selection and structural design to manufacturing processes.

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. This bearing type can simultaneously withstand radial loads and bidirectional axial loads, suitable for combined load conditions-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 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 and Lubrication 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. In hot rolling line applications, the adoption of fully sealed bearings significantly reduces routine greasing frequencyII. Core Product Advantages

Materials Science and High-Purity Control: 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. Improved material purity directly extends bearing rolling fatigue life-



.

Precision Heat Treatment: NMT employs controlled-atmosphere heat treatment and surface carburizing/induction hardening processes. Through precise control of carburizing, quenching and other process parameters, bearings achieve a “rigid yet tough” ideal state——hard and wear-resistant on the surface, tough and impact-resistant in the core. Raceway surfaces achieve a high-hardness hardened layer of HRC60-64 while the core maintains toughness. Steel materials经过 special thermal stabilization treatment, with retained austenite content controlled to extremely low levels, maintaining dimensional stability through repeated thermal cycling.

Targeted Structural Optimization: NMT performs customized design of cages, roller profiles and guidance structures according to the actual stress conditions of rolling mill bearings. Geometric profiling actively compensates for misalignment deformation, achieving stress uniformization. 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. Through optimization of main structural parameters and dynamic optimization design, the requirements for high load capacity, long life and high reliability in heavy-load mill bearings are met.

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. For high-speed applications such as Sendzimir mills, NMT adopts a unique component equal-life matching design principle, with optimized design of the contact surface edges of bearing outer rings.

Precision Manufacturing and Inspection: Production lines utilize high-precision grinding and superfinishing equipment, with critical processes completed in temperature-controlled clean environments. Raceway roundness, rolling element grading precision and other parameters are subject to precision inspection and matching. Critical dimensional tolerances are strictly controlled, with product precision grades meeting P5, P4 and higher requirements.

III. Typical Application Scenarios

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. In hot rolling lines, the application of fully sealed bearings significantly reduces grease consumption and waste grease pollution.

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. Cold rolling mill speeds are notably higher than hot rolling, with more strictly controlled thickness tolerances and higher surface quality requirements.

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). Bearings require high speed, high load capacity, high precision and long service life with intermittent alternating use. Achieving high load capacity and high precision within compact space, with bearing precision requirements reaching P4 or higher for matched sets.

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.

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. Through precise control of carburizing and quenching processes, an ideal “rigid yet tough” condition is achieved. 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. Production lines utilize high-precision grinding and superfinishing equipment. 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. For bearings used in matched sets such as Sendzimir mill bearings, section height differences within the same set and height differences between adjacent bearings are controlled to high standards. 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

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适配 different mill rigidity requirements. Products available in both open and fully sealed configurations-



.

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. Designed using a unique component equal-life matching design principle. Matched set precision requirements reaching P4 or higher.

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.

VI. Brand Strength

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

Technical Expertise: NMT channels decades of accumulated manufacturing experience into the specialized field of rolling mill bearings. From material selection and heat treatment to precision machining and inspection, every step is continuously optimized based on long-term application data. NMT emphasizes control of the fit precision between rolling elements and raceways, with “clearance” management running throughout the entire process of product design, manufacturing and assembly.

Manufacturing Capability: Production lines utilize high-precision grinding and superfinishing equipment, with critical processes completed in temperature-controlled clean environments. Product precision grades meet P5, P4 and higher requirements. For high-precision products such as Sendzimir mill bearings, dimensional consistency control within matched sets reaches high levels.

Application Experience: NMT bearings have accumulated 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.

Service Philosophy: NMT provides not only bearing products but also technical support services including selection consultation, installation guidance, operational assessment and failure analysis. Based on extensive experience in rolling mill bearing design, manufacturing and field application, combined with on-site bearing condition assessment and failure analysis, NMT helps users accurately identify bearing application issues and propose corresponding improvement measures.

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 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. In lubrication management, NMT provides standardized recommendations including oil line inspection, lubrication quantity optimization and daily oil level inspection.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.