A Long-Term Technical Partner for Global Steel Producers
Introduction
In today’s steel industry, rolling mill performance is increasingly defined by roll reliability, metallurgical consistency, and lifecycle cost, rather than unit price alone. For steel producers operating section mills, plate mills, and hot strip mills, selecting the right roll supplier directly impacts mill availability, product quality, and total operating cost.
Founded in 2003, LMM GROUP Roll Manufacturing has positioned itself as a specialized producer of large and heavy rolling mill rolls and roll rings, serving steel plants across North America, Europe, and Asia. With a clear focus on medium-to-large roll segments, LMM supports steelmakers seeking long campaign life, stable performance, and reduced unplanned downtime.
Company Background and Strategic Positioning
With over 20 years of metallurgical manufacturing experience, LMM GROUP has grown into one of China’s most technically capable roll manufacturers.
Key facts at a glance:
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Established: 2003
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Annual capacity: >90,000 metric tons
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Product focus: Large section mill rolls, roll rings, and hot strip mill work rolls
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Strategic direction: High-load, long-life, high-stability roll solutions
Rather than competing in low-end or commodity roll markets, LMM has deliberately focused on large-diameter, high-weight, and complex-pass rolls, where metallurgical control and process stability are critical.
In recent years, the company has expanded into:
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Hot strip mill work rolls
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Forged backup rolls (Phase II expansion)
Core Product Portfolio
1. Section Mill Rolls (Long Product Rolling)
Section mill rolls remain LMM’s core product line and are widely used in rolling lines for:
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H-beams
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I-beams
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Channels
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Angles
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Rails
Technical range:
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Roll diameter: Ø600 – Ø1800 mm
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Single roll weight: 3 – 50 tons
Section rolling imposes non-uniform stress distribution, complex pass geometry, and severe thermal cycling. LMM addresses these challenges through:
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Optimized alloy systems
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Controlled solidification during casting
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Precisely engineered heat treatment curves
Resulting performance advantages:
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Improved resistance to thermal cracking
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High wear resistance under heavy rolling loads
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Excellent dimensional stability over long rolling campaigns
These characteristics translate directly into extended roll life and fewer mill stoppages.
2. Roll Rings (Centrifugally Cast)
LMM produces roll rings primarily using advanced centrifugal casting technology, ensuring high density and metallurgical soundness.
Specifications:
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Outer diameter: Ø550 – Ø1800 mm
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Minimum inner diameter: 300 mm
Key advantages:
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Dense and uniform microstructure
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Strong metallurgical bonding between working layer and core
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Excellent fatigue resistance
Centrifugal casting is especially suitable for large-diameter roll rings, where structural uniformity and crack resistance are critical for high-load operation.
3. Hot Strip Mill Work Rolls
LMM GROUP currently supplies cast work rolls for hot strip mills, supporting modern high-capacity rolling lines.
Application range:
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Mill width: 1250 – 2250 mm
Reference customer:
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Gerdau (USA) – long-term supply relationship
These work rolls meet stringent requirements for:
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Surface quality
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Thermal stability
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Consistent hardness depth
They are designed for stable operation in continuous hot rolling environments.
Manufacturing Capability: Full Process Control
LMM operates a fully integrated production system, covering melting, refining, casting, heat treatment, and machining.
Maximum capabilities:
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Single-piece weight: 150 tons
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Maximum roll diameter: 2.5 meters
Melting and Secondary Refining
The melting shop is equipped with 15 medium-frequency induction furnaces, allowing precise matching between furnace size and roll weight.
Furnace configuration:
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3 t × 2 units
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5 t × 3 units
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8 t × 3 units
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12 t × 5 units
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20 t × 2 units
This flexible setup ensures:
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Stable superheat control
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Optimized alloy dissolution
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Improved energy efficiency
A 60-ton Ladle Furnace (LF) provides:
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Argon stirring
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Deoxidation and desulfurization
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Precise alloy adjustment
This stage is critical for minimizing non-metallic inclusions and dissolved gases, especially in large-section rolls.
Advanced Centrifugal Casting Technology
Centrifugal casting is a core strength of LMM.
Equipment overview:
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11 centrifugal casting machines
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8 horizontal machines (standard rolls and roll bodies)
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1 vertical machine (short and special geometries)
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2 disc-type machines (large roll rings and disc components)
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This setup enables centrifugal castings up to 2.5 meters in diameter, ensuring:
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Uniform working layer thickness
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Excellent shell-core bonding
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High metallurgical integrity
Heat Treatment and CNC Machining
Heat treatment:
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162 heat treatment furnaces
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Customized heating, soaking, and cooling curves for each roll grade
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Precise control of microstructure and hardness depth
Machining:
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Predominantly CNC-based equipment
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High accuracy in complex pass geometries
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Consistent surface finish and dimensional repeatability
Quality Assurance and Inspection
LMM applies a defect-prevention philosophy, recognizing that even minor defects can lead to catastrophic rolling incidents.
Inspection system:
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LISMAR Automatic Roll Inspection System (Netherlands)
Integrated NDT methods:
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Eddy Current Testing (ET): surface micro-cracks
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Ultrasonic Testing (UT): internal defects
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Surface Wave Testing (SW): near-surface integrity
On-Site Verification Example
During a recent technical audit, ultrasonic testing was conducted on an as-cast roll prior to heat treatment. Results confirmed exceptional internal density and homogeneity, demonstrating that roll quality is fundamentally established during melting and casting, not corrected afterward.
Phase II Expansion: Forged Backup Rolls
To meet growing demand for high-end products and reduce reliance on imported backup rolls, LMM is completing its Phase II expansion project.
Commissioning target: End of March (current year)
Key new equipment:
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50-ton Electric Arc Furnace (EAF)
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100-ton VD Vacuum Degassing Furnace
The VD system enables ultra-low hydrogen and oxygen levels, which are mandatory for forged backup roll production.
New capabilities:
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High-quality cast ingot production
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Planned launch of forged backup roll manufacturing
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Ability to supply complete roll packages (work rolls + backup rolls)
Global References and Long-Term Vision
LMM products are already in long-term service at leading steel producers, including:
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Hyundai Steel (Korea)
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POSCO Vietnam
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Gerdau (USA)
These references demonstrate stable performance under demanding industrial conditions. Building on its success in North America and Southeast Asia, LMM aims to become a long-term technical partner for global steel producers.
Conclusion
From its establishment in 2003 to its full-scale upgrade in 2026, LMM GROUP Roll Manufacturing has remained committed to one core principle:
Data-driven metallurgy and quality-first manufacturing.
Whether delivering 2.5-meter centrifugal cast rolls or producing ultra-clean steel through 100-ton VD refining, LMM continues to provide reliable, high-performance rolling solutions for the modern steel industry.
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