Technology

Danieli QSP®-Quality Strip Production to upgrade Nucor Steel Gallatin

ucor Steel Gallatin classical compact thin slab Bulfone expansion increases our Nproject introduction casting and rolling plant is Bilgen presence in the Midwest In order to extend the fully reconfigured into an Knights market, specifically in the range of steel grades and ultra-modern QSP®. Knigge automotive, agriculture, heavy increase production capacity, The revamped plant will Stenico equipment, and energy pipe Nucor has contracted include a new meltshop Da Costa and tube sectors." Danieli to upgrade its hot comprised of a high- Faralli Re-engineering Nucor Steel strip plant in Ghent, KY. performance DC EAF Danieli SpA Gallatin with QSP® The new plant featuring the Q-Melt In the spirit of full configuration - from package, twin ladle furnace partnership, the Nucor and compact thin slab casting and provision for a vacuum Danieli team of specialists and rolling plant to ultra- degasser in the future. agreed to re-engineer the modern QSP® (Quality Strip Both Nucor and Danieli plant by changing the Production)- will allow teams are committed to set original concept into an Nucor Steel Gallatin to a new benchmark in casting advanced QSP® plant improve thermomechanical and rolling technology. having improved rolling capabilities, therefore "This investment is thermomechanical rolling expanding production of another major component of capabilities, there by AHSS grades, API line pipe our strategy for long-term expanding production of steel grades and a number profitable growth,” explained AHSS grades, API line pipe of other added-value grades. Ladd Hall, EVP of Flat-Rolled steel grades and a number This is the first time that a Products at Nucor. This of other added-value grades.

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“For more than 20 years affecting the mill’s production. my work has been dedicated Furthermore, two new to thin slab casting and roughing mills will be added rolling and I personally to expand rolling capabilities. visited the Nucor Steel The independent high- Gallatin Plant the first time speed roughing, intermediate back in 2002. Looking at the transfer bar cooling and new plant concept, I am very final finishing rolling proud that Nucor and Danieli introduces the ability to teams together will convert perform a thermomechanical the existing concept into a rolling process, as is typical new generation of thin slab for conventional hot strip mills. casting and rolling plants,” control for the 188-sht DC This will lead to a said Christian Bilgen, EVP EAF, where Q-MELT Melt Model complete replacement of Rolling Technologies, dynamically will alter the EAF implementation the existing tunnel furnace, Danieli. “The possible profiles for the best practice, of a trend-based widening of the finishing mill product portfolio will be or by using mechatronic adaptive process equipment, new run-out table significantly widened, technologies that make it control. with advanced combined including thick API line pipe possible to conduct majority intensive and laminar cooling steels, and the product of the operations remotely and two new downcoilers quality will be considerably from the main pulpits. Safety with coil handling. increased.” and productivity are the The vertical-curved caster pillars that will guarantee the The revamped plant will will be equipped with a success of this project.” include a high-performance complete suite of advanced DC EAF and Twin LMF, with If for the meltshop the technological packages, provision for vacuum project foresees doubling Both Nucor including Danieli’s latest degassing in the future. production by installing a and Danieli design of multi-mode new production unit, the Being equipped with teams are electromagnetic brake (MM- state-of-the-art technology, design vision changes for committed to EMB) to ensure the control the new meltshop will make the casting and rolling plant. set a new of fluid dynamics within the use of the most recent After the upgrade, the benchmark in mould, enabling high process management tools. complete production will be throughput of quality thin slabs. delivered by a single-strand casting and One of these will be the new The tunnel furnace and vertical curved caster having rolling Q-MELT technological the heated transfer table a total capacity of up to 3.0 technology package, which is a key installed between the million shtpy. function for optimizing the roughing stands and finishing transformation costs. The new caster represents stands will be supplied by “The new meltshop shall the fifth generation of Danieli Danieli Centro Combustion. high-production slab casting be the most modern one in the Higher-quality, wider strip machines. The slab will be USA, where plant operations by Danieli QSP® at Nucor delivered to the rolling mill are surrounded by the latest Steel Gallatin steelmaking technologies,” by a new tunnel furnace via The six-stands finishing explained Paulo da Costa, a swivel-type ferry system. mill will be retained but it will Meltshop technical sales The new layout will allow for be widened and upgraded manager for Danieli. the installation of the new with new interstand guides, “Industry 4.0 is a key aspect caster and first portion of loopers and a new bending in the process control, either the tunnel furnace and and shifting system. This will by applying adaptive process swivel system without

STEELWORLD 44 May 2019 Technology allow Nucor Steel Gallatin to maximum advantage of the steel grades used for flat roll strips as wide as 1,870 the annual maintenance product applications, mm (73.5 in). To further outages already planned including the most enhance the performance of by the plant. demanding ones, such as the finishing mill, the first During the last shutdown advanced high strength three rolling stands will be the complete roughing mill steels, micro-alloyed, silicon reinforced to withstand group, previously steels for the most higher rolling forces. preassembled off-line, will sophisticated applications, Two new powerful be moved in line via a lift- such as automotive and roughing stands and a shift system. The pipe , vertical edger will be foundations of the mills will Over the last including Arctic applications. installed ahead of the be prepared under the 25 years the > Extending the range of finishing mill. With its total existing tunnel furnace thin slab final strip thicknesses to draft of 100 mm, the without interfering with the casting and include ultra-thin gauges powerful edger allows the production. rolling (TSCR) below 1.0 mm. full recrystallization of the With this project to process has The separation of the slab edges and makes it convert a compact mill into been gaining roughing stands from the possible to expand the a QSP® plant at Nucor Steel a major market finishing stands and the use capacity of the plant when Gallatin, together with a share in the of a vertical curved caster producing narrow products. high-performance meltshop, production of with thicker slabs is the Optimizing implementation, the Nucor and Danieli teams hot rolled strip, distinctive concept of operation are determined to establish progressively Danieli’s QSP®.It is the The complete process a new benchmark casting decreasing the result of more than 25 years control from melting to and rolling plant throughout exclusive of experience and R&D. finished hot-rolled coils will the world. advantages of The first plant ever installed be developed by Danieli Danieli QSP® Technology / conventional mills with this configuration was Automation. The challenge Concept, history and evolution the North Star BlueScope is to optimize the operation Over the last 25 years the QSP® in operation at Delta between the existing and the thin slab casting and rolling (OH) since 1997. It was new meltshop, while (TSCR) process has been followed by Algoma Steel controlling the quality of the gaining a major market (Canada) in that same year, caster and QSP®. As part of share in the production of hot and later by Ezz Flat Steel the implementation strategy, rolled strip, progressively (Egypt), OMK (), MMK the new automation system decreasing the exclusive (Turkey), NMDC (), will shadow and parallel the advantages of conventional SGJT () and Hoa Phat current automation systems mills. Danieli has developed to allow seamless switchover a complete portfolio of plant to the new automation. The layouts adopting TSCR automation system will be technologies, each of these designed for integrating the conceived to guarantee the industry 4.0 concept. optimal CapEx and The project will be OpExparametersin line with implemented over a market requirements: sequence of three carefully > Exceeding production planned mill shutdowns of 3.0 million tons per year. after 9, 15 and 23 month. > Expanding the product The strategy will take mix to include virtually all

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produce the highest range of grades using the controlled metallurgical technology with "two-step rolling", thermomechanical rolling in particular, due to the special layout features exclusively installed in this High productivity plant configuration. TSC, equipped The thicker slabs and the with 3Q superior temperature control technologies. of the QSP® layout mean that eight rolling stands can (). and maximum flexibility in be installed (2 RM + 6 FM) to selecting the slab thickness, Different plant configurations produce a complete range according to both for HRC production of products, including light productivity and quality The Danieli Wean United gauge strip down to a requested by the mill. QSP® (Quality Strip thickness of 1.0 mm in coil- Production) is a technology Compared with other to-coil rolling mode. The for thin slab casting and rolling mill configurations, investment required to rolling plants designed where all rolling stands are implement the QSP® according to the specific arranged together and configuration is fully repaid needs of the product mix operate as a single Finishing by the possibility of mass and production capacity. Mill, Danieli identified several producing products with mill-stand arrangements with Soon after the first The two main high added value, which separate roughing stands pioneering applications of areas on which means that the plant is very and finishing stands in order thin slab casting and rolling Danieli profitable even with only one to apply advanced rolling technologies in the late 1980s, introduced its casting strand, without the practices typically adopted Danieli recognized the innovative and need for future expansion. in conventional Hot Strip Mills, necessity to develop its own The QSP® layout provides such as thermomechanical comprehensive design concept to overcome approach are several advantages that lead the limitations of “first rolling. The number of the thin slab to superior strip quality: generation” plants in terms stands is selected according caster design > Vertical edger attached of quality and productivity. to targeted slab thickness and the to the roughing mill for The two main areas on which and final coil gauge. configuration accurate strip width control. Danieli introduced its innovative The QSP® layout is of the rolling mill > Separated roughing mill and comprehensive approach recommended for very and finishing mill to increase are the thin slab caster demanding customers who the overall flexibility of the design and the configuration want to produce the top plant and the steel grade of the rolling mill. range of commercial steel production range. Since its first pioneering grades. QSP® is designed to > Transfer bar furnace applications in 1985, the work with thicker slabs (up (TBF) to homogenize vertical curved caster design to 130 mm) than other thin transfer bar temperature, has been adopted, with slab technologies. This with consistent benefits in application of the patented makes it possible to terms of rolling stability in dynamic soft reduction increase production levels the finishing mill. process. This design allows up to 2.0 Mt/y with only one both superior slab quality casting strand, and to > Possibility of installing

STEELWORLD 46 May 2019 Technology an intermediate cooling The compact layout and Danieli concepts that system before the TBF when the tandem rolling of RM marked the progress of the API grades are produced. and FM make the plant thin-slab route, namely the > Three high-pressure suitable for semi-endless application of the vertical- descalers positioned rolling technology to produce curved design thin-slab throughout the mill to ensure ultra-light gauges below 1.0 caster, and the separation a superior quality strip surface. mm on seven stands (2 RM of the rolling stands into > Drum crop shear at FM + 5 FM), with the addition of high-reduction units and entry for safe and stable special machines such as a finishing units. threading during thin and high-speed shear, threading The market recognizes ultra-thin gauge rolling. device and high-speed significant extra margins coilers equipped with four An alternative QSP® for advanced high-strength wrapper rolls. layout is recognized by the products compared to marked being a perfect Danieli Universal Endless mass production of soft compromise between DUE® for no production and grades with lower investment cost and market limitations What makes revenues. At the same production capability. This Danieli, together with its the DUE® time, thin and ultra-thin QSP® layout is shorter, due customers, has progressively concept gauge products are to the fact that there is no developed a new generation different is generating significant TBF. This makes the layout thin-slab casting and rolling the ability profits. The DUE® very compact with the RM layout, marking a new phase to adopt technology ensures the and the FM coupled to work in the evolution of the QSP® “universal” success for the complete in tandem. The configuration process. The innovative rolling modes steel grade portfolio. has most of the advantages features of the process are Danieli Universal Endless of the QSP® (e.g., three embodied in the acronym constitutes a universal tool descaling points, vertical DUE®, which stands for able to reach all the production edger at RM, crop shear Danieli Universal Endless. requirements of the flat before FM, intermediate What makes the products market by applying cooling and advanced run DUE®concept different is the process that is best out table cooling system) in the ability to adopt suited to each steel grade a shorter layout. “universal” rolling modes and product. Endless and The product mix can cover resulting in the fact that coil-to-coil process modes, most market requirements. now, within a single plant, it thermo-mechanical rolling The absence of "two-step is possible to perform and multi-phase grades, rolling" (thus a long endless and coil-to-coil ultrathin and thick products intermediate table and rolling. This new approach all are now possible in a related TBF) only creates a can be seen as the natural Flexible mill single production line. limitation in special grades evolution of the original design. The ability to provide the to be produced with true mill with a thicker slab (110 thermo-mechanical mm), compared to the processes, such as thicker traditional thin-slab approach, pipeline grades API X70-X80 is reflected in the remarkable for Arctic applications. The increment in the reduction nominal slab thickness in ratio from slab to strip, this configuration is usually which in turn allows the 70 mm (with the possibility production of ultra-thin to reach 85 mm). gauges down to 0.8 mm and wall-thickness strips up to

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already successfully proven configuration with separation of the mill stands into high reduction units and finishing units, in order to perform the dual step rolling. The transfer bar area includes:

25 mm, in widths from 900 rolled coils, for a wide mix of > A drum crop shear for mm up to about 2000 mm. steel grades and strip cutting head and tail ends, achieving most stable rolling Slab-width change during dimensions from 0.80 to Nucor Gallatin_ conditions in coil-to-coil casting is an incorporated 12.7 mm thick and from 900 Layout 3D production modeand for function of the technology, to 1,600 mm wide. automated emergency thus further increasing plant The DUE® unique vertical- strategies in endless rolling. flexibility. Thanks to the curved caster features a 5.5 combination of slab m main radius, designed to > An induction heating thickness (110 mm) and operate with a single slab system designed and casting speed (over 6 m/min). thickness of 110 mm after manufactured in-house by Due to this the production dynamic soft reduction (130 Danieli Automation, for rates up to 3 Mtpy are mm at mould exit), with a consistent production of possible on a single casting casting speed in excess of 6 thin and ultra-thin gauges in strand, making the CapEx m/min, depending on the steel The first endless mode, which can be investment per ton grade. Such an unprecedented Danieli retracted off-line when not in use (i.e., during coil-to-coil extremely attractive. combination of slab thickness Universal production mode). The DUE® layout and speed makes it possible Endless plant, configuration, together with to easily reach the mass flow is installed in > A dedicated high- an effective combination of conditions required by the full the Caofeidian pressure descaling unit at the finishing mill entry (in thermal and electrical endless production mode, Industrial Area, addition to the one at high energy (gas-fired tunnel necessary for effective Tangshan City, reduction stand entry), to furnace and induction production of ultra-thin gauge. Hebei Province eliminate imprinting scale heating), optimizes energy The tunnel furnace, which for Shougang phenomena on the final strip. consumption, making DUE® is developed in-house by Jingtang > An intensive cooling a truly “green” plant while Danieli Centro Combustion, United Iron & system, incorporated into also reducing OpEx by about is approximately 80 m long Steel Co. Ltd. 15-20 % compared to the and provides a fundamental the descaler box at finishing (SGJT) current benchmark of thin- buffer function that increases mill entry, used when slab-based plants. plant flexibility. It allows the producing TMR and/or API The first Danieli Universal work roll change to be grades in order to guarantee Endless plant, is installed in performed as a background the correct bar temperature the Caofeidian Industrial task, without affecting the profile and to achieve proper Area, Tangshan City, Hebei operation of caster and control of grain growth, Province for Shougang meltshop, “switching” from which are essential features Jingtang United Iron & Steel endless to coil-to-coil operating of the thermo-mechanical Co. Ltd. (SGJT). Shougang mode during roll changes, rolling process. Jingtang’s DUE® plant will which in any case does not The mill stands, be designed for the reduce plant productivity. designed to guarantee production of 2,100,000 tpy The DUE® hot rolling mill superb geometrical and of high-value-added hot features a well-known and mechanical properties of the

STEELWORLD 48 May 2019 Technology final product, are equipped API X80) and in general of used for pipe applications, with all the state-of-the-art products with an excellent with approximately 50 % features for exceptional surface quality (98.6 % prime falling under API or similar strip crown and profile rated coils). Today OMK specification. control, bearing in mind operates the mill constantly OMK is using those pipe that these control functions above the rated capacity of grades in their own pipe also have to be operational 1.2 Mtpy and will achieve a shops to produce final under-load conditions as new production record this products for the oil and required by the endless year close to 1.3 Mtpy. gas pipe market. rolling process. The line is Talking about productivity, In 1997 Essar Steel Benxi Iron & completed with the laminar Tangshan Iron & Steel in Algoma in Canada became Steel (China) cooling system, consisting China was the first thin slab the first thin slab casting is a pioneer of a combination of power plant in the world to exceed and rolling plant in the in the and normal units for 3.0 Mtpy after adopting the world to produce peritectic production of outstanding strip cooling thin slab casting and rolling steel grades, as well as strategies, followed by the process in 2005. silicon steel HSLA grades like DSPC coiling area, made up of a The installation of a new using its thin 700 with a yield strength high-speed shear for intensive cooling unit in the slab casting exceeding 700 MPa, which cutting coils to length when ROT cooling section will technology to are used for example in the working in endless mode, help OMK to increase the produce automotive sector. pinch rolls and downcoilers. mechanical properties of the electrical steel Customers to whom Essar Danieli QSP® plant produced steel grades with a Si content Steel Algoma regularly performances (strength and impact of up to 3.2 % supplies these grades OMK Vyksa is a Danieli toughness) and opens up with more include all of the major single-strand QSP® plant the possibility to decrease than 4.0 m/min North American OEMs, with a plant layout similar high-cost alloying elements, casting speed. primary suppliers to the the one planned for Nucor such as manganese, silicon auto industry, major Gallatin. It starts with a and niobium. service centers in the casting machine QSP® final products Midwest, as well as Tier 1 producing 90 mm slabs, a The mentioned QSP® manufacturers (among 200 m tunnel furnace, two plant of OMK in Vyksais whom are the largest car powerful high-reduction one of the world’s powerful manufacturers in North stands, a transfer bar area thin slab plants for pipe America). with intermediate transfer grade production. In 2017 Looking into the market bar cooling and TBFthat is 99 % of the products were of electrical applications, followed by six finishing like the laminations for stands. Due to this flexible the cores of transformers plant layout, OMK is able and the stators and rotors to cover a wide range of of motors, Benxi Iron & products from thin gauges Steel (China) is a pioneer of 1.0 mm up to 12.7 mm in the production of of API grades for special silicon steel using its thin application in an overall slab casting technology to width range of 800 to produce electrical steel 1,800 mm. with a Si content of up to In 2015 the product mix 3.2 % with more than 4.0 consisted of more than 50 m/min casting speed. percent API grades (up to

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