Arvedi ESP — The best steelmaking knows no limits

What makes endless Hot Rolled Coils stand out: The endless material offers unprecedented uniformity and geometrical tolerances from coil head to tail. These factors become very important in terms of the yield for eHRC customers, as side trimming becomes obsolete and even decisive when stacking the material, e.g. for silicon steel’s application. 

The Endless Strip Production (ESP) process delivers outstanding surface quality. The clean surface after the caster, thanks to the stable mold level, is then preserved by descaling ahead of the finishing mill, oxidation prevention between mill stands, and the continuously maintained condition of the work rolls. If special grades that require ultra-high surface quality are produced, a retractable descaler can be installed in front of the high-reduction mill.

Arvedi Endless Strip Production (ESP) is the only process that reached 0.6 mm thickness on a hot rolled coil – this is a world record. It covers the full range from ultra-light gauges, to heavy gauges up to 25.4 millimeters (one inch).

Since the Endless Strip Production (ESP) process meets the end product thicknesses for a very wide range of markets, the eHRC can be used as a direct application product, competing in the cold rolled strip market with incomparably low production costs due to the reduced number of production steps (omitting cold rolling and obligatory annealing). Arvedi ESP can partially substitute cold rolling and Endless Strip Production material can also be used directly for end products.

The uniform material properties of the eHRC make cold rolling and processing much easier, since there are no fluctuations within the incoming parameters. The reductions in cold rolling can be set to a minimum since the incoming eHRC gauges are smaller.

Endless Hot Rolled Coils (eHRCs) allow for higher sales margins, compared to conventional hot rolled coils, due to the price premium for better quality and extended possibility of direct application. Additionally, downstream processors are willing to pay premium prices due to the easier processing of the uniform strip.

Arvedi Endless Strip Production (ESP) is the only process with zero greenhouse gas emissions during casting and rolling. Since 2009, Arvedi ESP lines have produced over 100 million tonnes of green steel with zero direct CO₂ emissions, resulting in a total reduction of 31 million tonnes of CO₂ compared to traditional casting and rolling processes.

Arvedi Endless Strip Production (ESP) uses the energy of the hot strand for the first rolling step after casting. There is no requirement for a gas-fired long tunnel furnace. For the second rolling step, a 10 m-long inductive heater provides the required temperature. The inductive heater can be switched off in idle times as there is no danger of destroying refractory material.

Due to its compactness with lengths below 180 meters Arvedi Endless Strip Production (ESP) stands for minimum temperature loss and an unbeatable low energy consumption.

With its compact design, Endless Strip Production (ESP) saves up to 50 percent of length and, respectively, area compared to other thin-slab casting and rolling processes. Compared to conventional routes, ESP saves up to 80 percent of area in green steelmaking.

Arvedi Endless Strip Production (ESP) offers you everything from commodity and commercial segments to the most sophisticated applications. eHRC products are found in all steel grade families, from high formability to high strength. The ESP proves to be the perfect transition technology to change from hot strip mill product mixes to endless production.

During operation, Arvedi Endless Strip Production (ESP) offers you the following flexible options:

• Steel grade changes are handled fully automated in the tundish. Level 2 support is given by the Intermix Expert model.
• The width is controlled directly in the mold with the reliable DynaWidth hydraulic taper and width control. The stable conditions of endless rolling are crucial to the highest width accuracy.
• Thickness is controlled throughout the sequence by patented flying gauge changes, which omit off-gauge production during thickness changes in endless mode.

Inline work roll change in the last finishing stands during ongoing hot rolling allows the highest sequence lengths without needing to hold a buffer, just as CO2-emitting tunnel furnaces do.

Due to its compact design, Endless Strip Production (ESP) can perfectly cope with higher amounts of tramp elements (such as copper) in a scrap-based EAF production since there is little time for copper enrichment on the surface (no tunnel furnace) before the first rolling step. The steel on the Arvedi ESP line stays in the critical temperature range for selective oxidation for only 1 minute, while on tunnel furnace TSCR, it takes 15 to 30 minutes.

With its compact design, Endless Strip Production (ESP) saves up to 50 percent of length and, respectively, area compared to other thin-slab casting and rolling processes. Compared to conventional routes, ESP saves up to 80 percent of area in steelmaking.

Beside the fact of less land consumption, ESP reduces Capital Expenditures (CapEx) drastically, requiring

• minimum foundations
• less steel structure
• less cladding
• less roofing
• less piping
• less cabling

Energy is saved through the compact design, using the heat of the hot strand for the first rolling step, and by efficient inductive heating, consuming energy only when the plant is actively casting and rolling.
Operational supplies are saved by drastically reduced maintenance at the extremely short inductive heater, as well as the doubled work roll lifetime due to endless operation.
Yield is increased by avoiding head and tail losses in endless operation, and the short oxidation time in the compact layout leads to only minimum surface scale.
Personnel costs are reduced by operating only one strand and omitting slab storage operations.

The dedicated endless production line omits the compromises of other production modes like coil-to-coil, and its numerous advantages outweigh the pretended flexibility of multiple production modes.

Arvedi Endless Strip Production (ESP) has less work roll wear as the endless process avoids shocks and damages to work rolls from slab threading. As the first rolling step happens directly to the cast strand with soft core, the strip is perfectly formed at lower forces. In the finishing mill wear-compensation work roll shifting in final mill stands doubles the work roll lifetime, compared to other processes.

Thermomechanical rolling of HSLA or API grades require to stay below the non-recrystallization temperature which is ensured by over-alloying. Contrary to this strategy, ESP's stable endless operation and high cooling rates by Ultra Early Power Cooling are advantageous to omitting such such over-alloying. This allows for a reduction in necessary alloying elements like Nb, Ni, Cr, or Mo.

Since 2009, Arvedi ESP technology has produced around 100 million tonnes of green steel in endless mode(eHRC). The experience gained through these years is reflected in today’s endless steel production layout and features.

In a history full of records we can look back on 9 running Endless Strip Production (ESP) installations worldwide, which set new standards by their performance. Two more will start up soon.

The upgraded Arvedi Endless Strip Production (ESP) line in Cremona, Italy performs at a world record mass flow of 7.1 t/min, which can be extrapolated into 3 Mtpy. With the target of producing more than 4 Mtpy on one strand soon, we work to ensure a gradual and realistic increase of mass flow, while maintaining stable plant operation and highest quality requirements.

Arvedi Endless Strip Production (ESP) has the most sophisticated emergency concept with the highest reliability. In the- case of downstream stoppages, there is no need to send back full ladles or stop the sequence. Production can automatically switch to plate mode and select other products from the order book for further endless operation.​

Arvedi Endless Strip Production (ESP) quickly brings experienced users, as well as newcomers, to nominal capacity – in figures:

• 6 weeks have been achieved by an experienced ESP user
• 12 weeks have been achieved by an ESP newcomer

The architecture of Primetals Technologies' own Endless Strip Production (ESP) automation system is based on an integrated and unique approach. State-of-the-art technology, combined with artificial intelligence, provides excellent product quality.

Acciaieria Arvedi offers Endless Strip Production (ESP) customers of Primetals Technologies a unique opportunity to train their complete maintenance and operating personnel at the Arvedi ESP line in Italy. This exclusive hands-on training enables customers to gain the necessary experience before even starting up their own line, resulting in impressive ramp-up curves.