Long-product technologies highlighted at DIM 2024

The long-products session of Day 2 at the Fifth Danieli Innovaction Meeting could not open with any topic other than Danieli MIDA QLP-DUE minimills, which ensure the most competitive and green production of long products – rebar in bundles and spooled coils, wirerod, and now also merchant bars– in any condition.

Covered by numerous Danieli patents, MIDA QLP-DUE minimills incorporate Digimelter and Octo-caster, empowering stable and consistent endless casting-rolling –and more proprietary technolo-gies for thermomechanical rolling, direct bundling and spooling.

Octocaster mould technology allows billet casting operation at speeds up to 10 m/min, producing from 200,000 tpy to 1 Mtpy with a single strand. A steady, smooth and reliable endless production guarantees plant uptime exceeding 90%, along with an excellent yield from liquid steel to finished product reaching 99% when selling bars by weight, and exceeding 103% when selling bars by number.

MIDA QLP-DUE is a true technology revolution in competitive, green steelmaking for long products. 26 million tons of bar and wirerod have been produced worldwide by MIDA QLP-DUE technology, saving 5 billion kg of CO2 emissions per year because there is no gas-reheating.

Up to 48 USD/ton savings as compared to a conventional process are achieved.

Endless rolling is possible also by the installation of billet welders upstream rolling mills.

The combination of sixth-generation Danieli billet welders with bar spooling for coils up to 8 tons raises the level of torsion-free, quality bar production.

Endless welding rolling process –welding heads and tails of the billets feeding the mill– increases plant productivity up to 12% and improves material yield. Latest, sixth-generation Danieli Horizon-tal Billet Welders -HBW drastically decrease cleaning and maintenance downtime due to a new design that consequently increases production time.

Danieli spooling process is well proven for twist-free bar winding high-quality production of ultra-compact customized coils. When paired with HBW it allows savings in downstream operations up to 24 USD/ton.

Danieli mills are characterized by the “any size, any grade, at any time” concept for maximum flex-ibility in steel grades, rolling strategies, and quick size changes, including small orders.

Product diameters range from 4.5 to 28 mm, and thanks to high-speed rolling +15% productivity for small sizes is achieved, compared to traditional equipment. Everything that is required to change a section is fully automatic and automated. Only four to 15 minutes are required to change the entire mill, performing according to the “zero-man on the floor” principle. Patented TMB guar-antees ±0.10 mm with ≤60% ovality over the entire product mix. Optimal tension control rolling, as well as reduced inventory and consumption of rolling rings are ensured. HSS shears crop wirerod heads and tails at record speeds –up to 135.4 m/s for dia. 5.5 mm, automatically. The in-line ther-momechanical rolling ensures superior metallurgical and mechanical properties, improving steel strength, toughness and ductility, and high repeatability, meaning -20% product complaints.

Winning on odd-roll configurations for accuracy and flexibility, the “Drawer” –Danieli four-roll tech-nology– sets new standards for SBQ bars production.

By operating the innovative Drawer, SBQ producers forge the core of the bar and draw its sur-face, applying the specific rolling sequence –oval, rounded-square, pre-round, and round. Com-bining high-reduction and sizing on the bar, and with the 4-roll modules in sequence, means that the spread of the rolled product is “zero”. During the meeting at the Danieli Research Center, in-dustrial machine “Drawer Evo”, the new, superior-quality bar sizing block for operating in free-sizing mode for a wide range of bar diameters, was exhibited.

Consistent, high-quality in-line head-hardened rails up to 420 HB at the lowest transformation costs are achieved by using the Danieli RH2 in-line Rail Head-Hardening proprietary quenching system.

Danieli RH2 is energy-saving since no air blowers are used for quenching (45% lower production cost) and no additional heating devices are required for head/tail temperature equalization (35% lower power consumption compared to running through systems).

The most recent RH2 rail-hardening system is in operation at ArcelorMittal Poland in Dabrowa Górnicza. With rail lengths up to 128 m, linear weights between 45 and 68 kg/m, and hardness lev-els up to 420 HB at a productivity rate of 22.5 rails/hour, this installation will become the new benchmark.

Cost-efficient Danieli proprietary QST –Quenching and Self-Tempering process achieves high yield strength, good toughness, and weldability without the expense of alloying.

QST is an in-line heat treatment for structural beams after rolling that makes it possible to produce fine-grained HSLA structural grades according to the European (EN10025) and American (A913/A913M) standards.

Intensive water cooling is applied to the beam surfaces. After quenching, the outer layers are tem-pered by the heat flux generated by the thermal gradient between the surface and the core, which is still hot.

Low-emission, multiline, quality bar quenching and tempering lines featuring inclined and shaped rolls allow continuous rotation of bars during their handling inside the austenitizing furnace and the quenching machine. This makes it possible to improve the quality of the bar homogeneity, at the same time minimizing the risk of deformation. This solution, combined with a series of expedients relating to the arrangement of the burners in the furnaces, and of the water or water/polymer spray nozzles in the quenching machine, guarantees excellent treatment uniformity and consequently a high-quality final product.

Danieli proprietary hydrogen-ready burners and combustion system allow 25% reduction of fuel consumption and emissions, with carbon emissions going to zero when using 100% hydrogen.

No-water-cooling system, reduced fuel consumption and reduced emissions are the main ad-vantages of Dry Plus walking-beam furnaces, which represent the latest progress in sustaina-ble reheating.

Also featuring hydrogen-ready burners, the “dry” solution contributes substantially to reducing carbon emissions by 20% and specific energy consumption. Dry Plus Furnace does not require the installation of a water-treatment plant, delivers increased billet heating quality, and allows an overall OpEx reduction up to 18%. Further savings attributed to the Dry Plus Furnace come from a reduced installation time (in the range of 20%).

A carbon and NOx-free, fully electric soaking furnace designed by Danieli Centro Combustion has been running at Fagersta Stainless Steel, maintaining billet temperature between reheating furnace and rolling mill. The electrical coils that provide the heat to the billets are positioned along the entire length of the furnace roof and walls, with a supporting system originally designed and tested at the Danieli Research Center, making it possible to maintain the furnace chamber at temperatures up to 1250 °C, never before reached with this type of heating system.

Increased yield and reduced fuel consumption and emissions are accomplished by operating new, Danieli-patented scale-free furnaces.

The most effective way to reduce the scale formation is to decrease the oxygen content in the fur-nace high-temperature zones. Two scale-free furnaces are operating in Italy and USA, and a third one is being installed in Mexico.

The relevant technology, compared to a traditional walking-beam furnace, besides drastically re-ducing scale formation down to 50%, also reduces fuel consumption by 5% and related carbon emissions in special and carbon steel grades production.

SuperGrinder and IntelliGrind® surface-defect inspection are the technologies for defect-free stain-less, alloy, automotive and carbon steel grade slabs. By using them, hot-slab grinding up to 900 °C, for automated, highly efficient surface removal and increased productivity are performed. The automation system manages material removal, with real-time comparison between MRR and Q-Ratio theoretical and verified values.

Fully electric Evo grinders plus automatic inspection and optimized control functions allow 25% lower energy consumption and clean operation.

The IntelliGrind® surface-defect inspection system featuring AI combines high-definition image ac-quisition and laser sectioning with automatic detection and classification. Hi-Grind dynamic pres-sure regulation optimizes control of removal depth within +/-10% of the input value. Danieli Automa-tion TWS system interface manages the plant in fully automated mode, with control of grinding reci-pes, Metal Removal Rate, wheels stock and selection management, and material tracking.

With reference to Danieli Automation and DigiMet, production, process, quality and energy man-agement with a unified digital platform simplifies metal production complexity. Designed to be inte-grated into existing IT/OT networks, on-premises or hybrid installations, the user-friendly Q3 plat-form is scalable and centered on data, process and people. Q3 focuses on optimizing the entire business process chain within a plant, addressing efficiency and resilience challenges in the met-als industry.

Danieli Automation Q-Robots provide performance efficiency as well as added value through intel-ligent solutions capable of learning from the context and optimizing operations, in terms of accura-cy, repetitiveness and safety. Localized intelligence is gathered by integrated autonomous func-tions that allow Q-Robots to work independently with limited external input and computational re-sources.

Shifting from product-based to service-based models, Danieli Automation native-designed, ad-vanced monitoring and maintenance services offer servitization to the metals industry.

By remotely monitoring the performance and condition of the assets, it is possible to detect early signs of equipment failure, schedule proactive maintenance, and minimize the impact of any breakdown in customer operations.

The next NewsFlash on the Fifth Danieli Innovaction Meetings will report on the “Tubes and pipes” presentations there, and complete the reports of the technology sessions.