Rautaruukki Manages World-ClassSteel Production With ABB automation

Rautaruukki, one of Europe’s leadingproducers of coated steel strip and high-quality galvanized steel products, has built anew galvanizing line with the most moderntechnology. ABB supplied a major packageof systems and services. The entireproduction line is controlled by an ABBautomation system. The new line started upahead of schedule.

At the inauguration of new galvanizing lineno. 3, Project Director Pentti Pirkola fromRautaruukki had good reason to be happywith the excellent results of the project.Efficient cooperation between Rautaruukki'sown people, external contractors and anumber of equipment suppliers resulted inthe new line starting up almost a monthahead of schedule in spring 2000.

The construction of galvanizing line 3 atRautaruukki´s Hämeenlinna works in Finlandwas a logical continuation of Rautaruukki'sextensive investment program, started at thecompany's Raahe Steel Works and continuedat the Hämeenlinna works. The investmenthas increased Rautaruukki's galvanizingcapacity to 900,000 tonnes per year. The newline alone boosted output by 450,000 tonnesper year.

People working at Rautaruukki call the newline "the most modern tool of the 21st century".In terms of technology, level of automationand product range, it is unique.

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ABB bore a great responsibilityABB delivered the process automation and adrive system as well as all related services toRautaruukki.

The drive system consists of a switchgear forthe strip transfer system and two switchgearsfor drives. The striptransfer system containsapproximately 130 drive sections and aninverter supply unit as a power supply section.There are 19 controlled fan drives in the

The Level 2 automation system supplied byABB contains, for example, integratedmathematical models of sub-processes andinterfaces, both with process equipment andRautaruukki's Manufacturing Execution System.

In addition, ABB's responsibilities includedhardware and software engineering, start-upand commissioning of the automation system,and personnel training.

system. The drives are controlled by AC 80application controllers and the automationsystem uses Advant Controller 450 processcontrollers. The man-machine interfacescomprise Advant Station 520 operator stations.

System programming, installations, cabling,start-up, commissioning and training wereimportant aspects of ABB's contribution. Thisparticular drive system is distinguished by anautomatic line shutdown feature used in theevent of an unexpected power failure whichmaintains strip tension control, thus avoidingstrip breakage and process equipmentmalfunctions.

An ABB open control system was used forthe Level 1 automation of the galvanizingline. The system comprises eight AC 450process controllers, eleven processors andthirteen AS 520 operator stations. Processinterfaces were established with a distributedS800 I/O system.

All systems integratedBased on ABB’s wide experience, ABB wasresponsible for the whole process automationdelivery. The basic automation, Level 1, wasbuilt based on descriptions and requirementsof other suppliers as well as on systemoperators’ wishes. "The automation systemcontrols coil handling at the beginning andend of the process, strip transfer along theproduction line and connections to thesectional drives" reports Jari Sivula,Production Manager at Rautaruukki.

"ABB tuned the entire system into anintegrated whole, which is very important ina continuous process like ours. The lowestlevel in the automation hierarchy, Level 1,controls drives, measurements and sub-processes. In other words, the basic automa-tion covers all the physical functions of thegalvanizing line. Integrated with the basicautomation, the system also comprises Level2, i.e. the ABB control system, which in turncommunicates with a higher-level system or,

in practice, Level 3, which is controlled by theplant's main computer. The interface betweenRautaruukki's own system and the ABBsystem is the one between Levels 2 and 3",he continues.

Entire production line controlledby only one user interfaceThe main idea behind the automation systemwas to provide a common user interface forcontrolling the process and automation systemboth for operators and maintenance personnel.According to Jari Sivula, ABB accomplishedthis very successfully.

The assignment presented a major challengeand tough requirements. The process must becontrolled by a single automation system. Thesystem must be easy to operate even in themost demanding sub-processes. The mostdifficult ones, as regards automation, includestarting a new coil and welding to the previouscoil, preparing coil ends, threading the stripend and simultaneously controlling all theprocedures. It is vital to be able to control the

The whole process is composed of equipmentsupplied by several companies. Everythinghad to be integrated into one single system.There were dozens of process descriptions ofvaried quality, reflecting several kinds ofcorporate philosophies."

“Some of the glory belongs to RautaruukkiEngineering, who were responsible for theoverall project management and planning.The production department at the Hämeenlin-na Works did their share by transferringoperators from the old production line to theproject at a very early stage. In this way, theoperators were able contribute their needsand opinions at a sufficiently early stage to betaken into account and they could also betrained for their new duties. All these factorscontributed to our successful start-up,"continues Sivula, Production Manager for thegalvanizing lines at the Rautaruukki Hämeen-linna Works.

critical processes all the time: in the continuoussub-processes, such as the annealing furnace,which generates temperatures above 800oC, abreakage of the strip always results in days ofdowntime and several tonnes of scrap.

"ABB managed the project outstandingly, eventhough we had allowed relatively little time forABB to start the system and set up and fine-tune the functions," Jari Sivula says. "ABB dida great job, which undoubtedly was not easy.

"High tech high touch" processtechnologyThe designers and constructors of galvanizingLine 3 were able to draw on the experience ofRautaruukki and equipment suppliers whohave been working with hot-dip zinc coatingtechnology for decades. Reliability andconfidence are of the utmost importance,because the process is so complicated. Thesame production line runs continuous andbatch processes simultaneously. Any stops

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and breaks would cause significant financiallosses.

The strip coil to be galvanized weighsapproximately 30 tonnes. The production linehas two uncoilers. The strip ends are preparedand welded together automatically to form asingle continuous strip for the galvanizingprocess. The strip then undergoes chemicalcleaning, comprising several stages andprocesses. The entry stage comprises avertical-type entry accumulator with amaximum capacity of 320 meters.

The line's annealing furnace has a natural gasfired preheating stage and a soaking stagewhere the strip is heated by radiant tubes. Inthe furnace sections after the soaking stage,the strip can be cooled down either slowly orrapidly. The temperature of the strip is thenequalized in an electrically heated equalizationsection prior to the actual hot-dip zinc coating.

The galvanizing section is equipped with twointerchangeable zinc pots so as to produceeither Galvannealed products or GALFANcoated products.

The new galvanizing line comprises a widevariety of post-treatment options. Chemicalpost-treatments include chemical passivationby means of a sprayed solution process ororganic AFP coating applied by a coatingmachine and dried in a furnace afterwards.

At the exit section of the process there is anaccumulator similar to the one at the entry ofthe line. The surface quality of the strip canbe inspected on both sides, regardless ofwhether the strip travels vertically orhorizontally. At the end of the line, thefinished strip is cut with a shear into coilsaccording to the weights specified by thecustomer. The coils are automatically weighed,marked and banded, and removed to thepackaging station beside the galvanizing line.