When Wi-Fi reached its limits, ArcelorMittal France rebuilt connectivity with private 5G

Steel plants are among the most challenging wireless environments in the world.

At ArcelorMittal France, dense metal structures, electromagnetic interference, and vast outdoor operations pushed Wi-Fi beyond its limits—creating coverage gaps, manual workarounds, and blind spots across critical processes.

To move forward, the company didn’t simply upgrade Wi-Fi. It shifted to a new connectivity model built around private 5G for industrial-scale operations.

Working with Ericsson and Orange Business, ArcelorMittal deployed “5G Steel”—France’s largest private industrial cellular network—across its Dunkirk and Mardyck steelmaking and recycling facilities, with a second core deployed at Florange. The network now delivers full-site connectivity across blast furnaces, rolling mills, and scrap yards in one of Europe’s most demanding radio environments—achieving a 5X cost advantage and ROI in under two years.

At Dunkirk and Mardyck, conventional wireless infrastructure had reached its limits.

Electromagnetic interference from blast furnaces, rolling mills, and dense steel structures made Wi-Fi unreliable and inconsistent. Large areas—including entire scrap yards—were effectively disconnected.

This created:

• Blind spots in material tracking
• Fragmented maintenance workflows
• Workers forced into manual or paper-based processes
• Frequent movement to “connected zones” just to access systems

At the same time, the business pressure intensified:

• Global steel oversupply increased pricing pressure
• Decarbonization targets required major capital investment
• Operational efficiency became a competitive necessity, not an improvement

ArcelorMittal France needed more than an upgrade.

It needed deterministic, industrial-grade connectivity across the entire plant floor.

Ericsson was selected to design and deploy a fully industrial private 5G architecture. The network—branded "5G Steel" and supported by the France 2030 initiative—was engineered end-to-end to serve current and future applications across multiple sites.

Ericsson led radio network design, simulation, integration, acceptance testing, and optimization. 

Core infrastructure included:

• Ericsson macro radios (4418 B38, 4422 B77)
• BBU 6631 baseband units
• Radio Dot systems for indoor precision coverage
• Dedicated private 5G core at Dunkirk
• Ericsson EP5G platform at Florange (migration underway)

Extensive RF modeling and simulation ensured performance compliance, including cross-border spectrum considerations near Belgium.

ArcelorMittal France operates the network internally, managing daily operations and first-line support, while Ericsson provides second-line support and specialist expertise for advanced technical support.

Connected workers on the production floor

Workers across ArcelorMittal France's facilities now use tablets with real-time access to:

• Equipment status
• Maintenance instructions
• Quality and production data, 

In rolling mills over 700 meters long, private 5G eliminated wasted time caused by disconnected zones.

Technicians can now:

• Tag equipment in the field
• Log maintenance instantly
• Complete workflows without returning to control rooms

Scrap yard visibility and recycled steel throughput

Previously unconnected scrap yards are now fully integrated into plant systems.

Operators gain real-time visibility into:

• Material flow
• Equipment status
• Processing efficiency

This directly supports ArcelorMittal France’s goal of increasing recycled steel output by one million metric tons.

AI-based vision systems for rail operations

At Mardyck, AI-powered vision systems connected via private 5G deliver real-time monitoring of train operations in push mode.

Autonomous rail and road vehicles are currently being tested, enabled by low-latency private 5G connectivity.

Future-ready infrastructure at the new Mardyck electrical steel plant

At the new electrical steel plant in Mardyck (opening 2026), private 5G is embedded from day one.

Cranes, AGVs, and mobile systems will connect natively to the network, based on learnings from four years of live industrial operation.

ArcelorMittal France’s private 5G deployment delivered measurable impact across cost efficiency, operational performance, and long-term industrial transformation—while establishing a blueprint for future steel facilities.

Financial and infrastructure performance

• ROI achieved in under two years across Dunkirk and Mardyck deployments
• 5X cost advantage versus Wi-Fi across the same industrial footprint
• Lower energy consumption than Wi-Fi at scale, supporting ArcelorMittal France’s decarbonization roadmap and 90% emissions reduction target for steel by 2050

Operational transformation

• Scrap yards fully connected for the first time, enabling real-time visibility into material flows and equipment performance
• Connected-worker applications deployed across production environments, giving workers instant access to equipment status and maintenance procedures in rolling mills, blast furnaces, and outdoor facilities
• AI-based vision systems implemented for rail operations at Mardyck, with autonomous rail and road vehicle testing now underway

Strategic platform impact

• The new electrical steel plant at Mardyck (opening 2026) is designed with private 5G as foundational infrastructure, not an add-on—setting a new baseline for all future ArcelorMittal France facilities