Report on best available techniques bat in the german ferrous metals processing industry final draft deutschfranzosisches institut fur umweltforschung dfiu. Blazevic in this fourth volume of hot strip mill operations, the primary objectives are to separate localized shape distortions, such as buildup, from general shape problems, and to explain how buildup goes through the hot strip and cold strip mills. Properties of hot rolled strip obtained by calculation or. The role of a hot strip mill hsm is to produce strips from semifinished steel slabs.
Avestas hot strip mill make thin stainless steel strips between 2. Deutschfranzosisches institut fur umweltforschung dfiu. The dimensional quality specification,4 consisting of thickness, width, flatness, and. Risk analysis causing downtimes in production process of hot rolling.
Advantagesofaluminum thepropertiesofaluminummakeitoneofthe mostadvantageousandversatilematerialsin usetoday. This paper describes first the background to the introduction of press equipment, the production speed of which was a matter of concern, into the conventional hot strip mill lines that were massproducing strips with rolling equipment rolling mills only. In hot strip mills this problem is mostly restricted to the first and last 30 m of the strip. Mill spring is a defect in which the rolled sheet is thicker than the required thickness because, the rolls get deflected by high rolling forces. The objective of a hot strip mill process is to produce a strip coil of a specified width and thickness. Strip is the product with a thickness mill products further rolling steps bloom billet slap is the hot rolled ingot cross sectional area 100 cm2 and with a. Past studies reveal that roll lubrication can reduce the mill separating forcetorque5 and the tertiary scale thickness. Tandem hot strip mills were, and are still being, constructed in numbers in china and some other countries, and many of these latest hot strip mills have quality improvement measures such as coil boxes. The sevenstand hot rolling mill, figure 4, processes the slabs into either thin strip down to 1. Hot strip mills have evolved in various steps from original tinplate and sheet rolling. In cold and hot tandem mills or continuous annealing process lines, which required high. Processing, structure, and performance, 2nd edition scale, hot strip mill operations, vol.
If the crown of the hot strip, which determines the profile of the cold strip, is too high or too sharp, the result may be a narrow but very pronounced. Hsmm is one of several commercially licensed technologies developed under aisis advanced process control programme, a collaborative effort among steelmakers and the u. In hydromechanical descaling processes the jets are formed by special descaling nozzles which are arranged on spray headers in a so called descaling box or mill descalers through which the product slab, strip, billet, bloom, beam blanket, etc. The complete technology book on hot rolling of steel. Productivity and quality improvement through setting. In the working process of the coiler, from the strip head. The centerliner is designed to measure the position of the strip in the finishing mill. Hot rolled products analyst site visit process cont. For thicker gauge steel, a 60 second hold time and 12% roughing mill reduction increase should be applied to. By now, kashimas two hot rolling mills, namely plate mill and hot strip mill, are operating.
Hot rolled, pickled coils are fed into the cold rolling mill from an entryend reel and progressively reduced in thickness in each stand to achieve the final desired thickness as the strip exits the last stand. A multistand hot strip rolling mill has a pinch roll assembly 4 downstream of the last stand 1 and before the coiler and a shapemeter roll 5 is located between the last stand 1 and the pinch roll assembly 4 so as to engage with the strip. This modernization measure ensures the operational reliability of the drive train, prepares the mill for a future extension and reduces mill maintenance. In flat rolling the final shape of the product is either classed as sheet, also called strip thickness less than 3 mm, or plate thickness more than 3 mm. The finishing end of the mill layout and temperature measuring instruments are shown on fig. Achieving these objectives will allow hot mill operators to concentrate their efforts on the critical aspects of the rolling practices to eliminate many types of shape and profile problems, to reduce the shape and profile problems for their customers, and to enhance the consistency of the shape and profile quality produced on hot strip and. Overview of the steelmaking process pellets sinter limestone coke iron ore coal scrap blast furnace ironmaking converter steelmaking ladle refining blast furnace steelmaking coalnatural gas plate hot rolled bars rods tube rounds rails slab billet bloom hot rolled and coldrolled strip coils structural shapes. The demands of operators, roll manufacturers, and mill builders for low roll wear, prevention of roll breakage, good shape, minimizing fire cracking and surface appearance are all inclusive in roll.
Recognizing that tension can be used to manipulate the strip width in the finishing mill, modelbased width control compensates. Rolling is a process that is widely used and has very high production. It is able to predict the mechanical properties as well as the thickness and composition of the scale layer of the hot rolled strip immediately after cooling and downcoiling a simulation of all process steps such as austenitization. Rolling is a metal forming process in which metal stock is passed through a pair of rolls. Sms siemag hot strip mills 2 adapting existing hot strip mills to presentday market requirements owing to their size and high investment volume, hot strip mills have an extremely long life.
Compact strip production csp, or in conventional hot strip mills, has increased the requirements for precise massflow and thickness control. Hot strip mill layout this new hot rolling mill figure 1 was designed to produce strip up to 1,880 mm wide with a final thickness down to 1. The transfer bar from the reversing rougher was coiled in the coil box and uncoiled into the finishing mill. Long product mill a light and medium merchant mill bar mill. The rougher r5 is the last of four nonreversing stands in the fivestand roughing mill of arcelormittals hot strip mill in dunkirk, france. Its cost could be very high due to the reduced strip quality and equipment damage. Its products include gas pipes and water pipes that will be of help in rebuilding the. Report on best available techniques bat in the german. Index termshot strip mill, polytopic uncertainties, robustness, singular perturbation, steering control. Camber is a phenomenon that occurs in plate mills mainly concerning the whole plate as well as in hot rolling mills mostly limited to the crops. The strip position is essentially important for the geometric strip quality profile, flatness. Hot strip mill equipment layout and coiling temperature control pyrometers runout table f2 f3 f4 f5 f6 f7.
Epa contract number rti project number 68d10143 35u568158 dr steel pickling. Pdf skinpass rolling of steel strip using liquid nitrogen. Recent innovative solutions applied to modern steckel mills make it possible to achieve highquality strip that is comparable to the products of traditional hot rolling. Cold rolling is a process used to produce sheet and strip with superior surface finish and dimensional tolerances compared with hot rolled strip. Optimization of hot strip rolling mill process atlantis press.
There are two processes for the tinning of the black plates. Pdf microstructure modelling for line pipe steels in hot. Consistency from coil to coil is maintained by applying ladle metallurgy and continuous casting to molten steel, and rolling on a hot strip mill that features advanced process controls. These hot rolling technologies, coupled with stelcos strict composition. In addition, kashimas small diameter welded pipe mill restarted operation on april 12. Pdf designing of hot strip rolling mill control system. Right from the start of production, the hot strip mill exceeded the contractually agreed capacity. Steel plate is first slit to the correct width, the circumference of the finished pipe and the edges milled to ensure the blank is square and of the correct dimension. Sumitomo metals restarts operation of hot strip mill at. The hot rolling process the primary function of the hot strip mill is to reheat semifinished steel slabs of steel nearly to their melting point, then roll them thinner and longer through 12 successive rolling mill stands driven by motors totaling 77,000 hp, and finally coiling up the lengthened steel sheet for transport to the next process. Based on the experience gained from more than 60 drumtype shears built so far.
Stresses from hertzian pressure in 4high cold mill back up rolls were measured years ago, the results were never published, but of high interest also, maybe later. The plate was then tinned using the process outlined above. Loop monitoring and assessment of hot strip mill control. Fundamentals of roll cooling and control of flatness at. Almost 40 % of the 140 conventional hot strip mills currently in operation all over the world were built between 1960 and 1970. Every slab must be reheated in a reheat furnace before being rolled to produce steel coils in the next process, the hot rolling mill. Energy saving and process optimization in a conventional. As an initial step to meet these demands, primetals technologies has developed a new control concept for rolling ultrathin hot rolled strip in the finishing mill of an esp line.
Optical measurement systems for quality improvement in hot. A profile draft report december 1993 prepared for john robson u. Application of hot rolling lubrication on a reversing coil. Chatter is a common term for the intense, undesirable mill vibrations occurring in both hot and cold rolling. The large wheel for stand r3 in the hot strip mill of arcelormittal, dunkirk, with a diameter of nearly 4,500 milli. Microstructure modelling for line pipe steels in hot strip mill. Process rolling mills consists of different type of mills based on the desired products namely. An effective inter stand cooling in hot strip mill daniel hajduk ita ltd. The second volume of hot strip mill operations is aimed at one primary objective. In the 1970s, the steel company of canada stelco developed the hot strip mill coil box see figure 1. Analysis of a continuous heating process hot slab charging effects of skid system on heating 15. Inline skinpass mill for cold strip skinpass mills can also be installed directly inline in the exit section of an annealing or hot dip galvanizing line.
Secondary scale on hot strip and the impact on wear is another issue. Although inferior in productivity to a tandem hot strip mill, a steckel mill requires smaller capital investment and offers wider free. Early hot rolling strip mills did not produce strip suitable for tinning, but in 1929 cold rolling began to be used to reduce the gauge further, which made tinning achievable. The hot strip mill at rourkela steel plant is 1700 mm. Abstract rolling is a forming operation where plastic deformation of a work piece is. Nov 16, 2017 slab semi finished products plate is the product with a thickness 6 mm. Our hot rolled steels are produced to meet the chemistry and dimensional requirements of our customers. Thermomechanical model for rolling and cooling of hot. Robust steering control of hot strip mill ieee xplore. Hot strip mills began to apply the roll lubrication technology. Advanced automation system for dragon steels new hot.
In the process of rolling the most significant aspect is the generation of heat through friction and deformation in the roll bite and in a typical cold tandem mill, work roll temperatures normally fall in the range of 55oc 70oc with strip recoil temperatures and interstand strip temperature rarely exceeding 160 oc depending on product. Pdf on jan 3, 2020, d vanderschueren published 2020 technology and operation of a hot rolling mill find, read and cite all the research you need on. Advanced automation system for dragon steels new hot strip mill. Hot rolling is a process in a steel plant in which the semifinished slab is reheated to a predetermined temperature and the hot slab is rolled to make the specified hot strip in a coiled form. Enjoy the videos and music you love, upload original content, and share it all with friends, family, and the world on youtube. The strip can be completed in the process line, and this has several advantages. Analysis of roll stack deflection in a hot strip mill scielo. Products flat steckel mills a unique combination of. Hot strip mills 40 tons of hightech largest casehardened wheel from september 2011 until august 2012, a workpiece of a size that even the sms siemag workshop had never seen before passed the manufacturing process in hilchenbach. Comparison of layouts of compact hot strip mills be with layout of semicontinuous hot strip mill a classification of highproduction hot strip mills fully continuous hot strip mill without reduction initial band thickness 25mm initial band thickess 200250mm initial band thickess 50mm initial band thickess 25mm. Thermomechanical model for rolling and cooling of hot rolled. In special applications, the drumtype shear also serves to divide transfer bars and finished plates. Comprehensive shape control technology for csp hot strip mills.
Energy saving and process optimization in a conventional hot. Fly ing gauge change allows producing strips even below 1. Us steel ran this case for grade 50 steel in the hot strip mill trial 2. The strip is made from casted steel slabs and rolled in two stands down to desired thickness. Hot mill process parameters impacting on hot mill tertiary. The millconsists mainly of a singlestand reversing roughing mill with edger, a coil box and a 7stand finishing mill see fig. Universal mill 5stand four high hot strip mill hot bands coils to electrical and stainless finishing electric furnace aod lmf butler works stainless and electrical steel production flow process ak steel corporation 9227 centre pointe drive west chester, oh 45069 800. Csis hot strip mill includes six finishing mills, which reduce the thickness of the transfer bar down to the gauge required by the customer or the next process.
Hsm hot strip mill, descaling, rolled in scale, impact force, erosion pattern. The rolling speed is set to allow the last stand to perform the final reduction at the finishing temperature, between 1500 to 1650f, specified to reach certain mechanical properties. Scale removal from strip surface by high pressure water jet high pressure water jet is normally used to remove the scale from hot strip surface. The hot rolling process california steel industries. Its products include gas pipes and water pipes that will be of help in rebuilding the communities in earthquake stricken areas. Sms siemag hot strip mills 10 the drumtype shear installed between the roughing and finishing mills of a hot strip mill crops the transfer bar at its head and tail. Design requirements for a hot strip mill process computer system. Heat transfer during the rolling process workpiece temperature change in hot strip mill temperature loss due to radiation temperature loss due to convection temperature loss due to water cooling temperature loss due to conduction to work rolls.
The plant comprises a twostand reversing roughing mill with vertical edgers and a sevenstand finishing train with two downcoilers figure 2. On april 12, the hot strip mill at sumitomo metals kashima steelworks restarted operation for the first time since it was hit by the huge earthquake on march 11. Downstream of the tunnel furnace, a heightadjustable highpressure descaling system ensures a clean slab. Hot rolled carbon steel carbon steel types from ak steel. Multiplestand finishing group detection automatic andor visual inspection of the hot rolled strip surface during hot rolling and pickling defects prevention use of deburring machine. Pdf 2020 technology and operation of a hot rolling mill. Scale formation and its removal in hot rolling process. Multiple steel grades ranging from hsla, ultra low carbon, api to conventional steel grades within a range of 1. Rolling schedule plays a decisive role in rolling of strip steel, and has an important effect on capability of rolling mill. The hot rolling process california steel industries, inc. There are two types of rolling process flat and profile rolling. Camber is often the reason why plates cant be processed to get products of good quality.
Secondary scale is formed during the rolling process in the roughing mill area and tertiary scale within the finishing mill and coiling train. Jan 02, 2017 each stand has vertically stacked rolls that are powered by huge motors to impart high compressive stresses into the strip. If the strip is rolled after heating the strip above the recrystallization temperature then it is termed as hot rolled and if that done in room temperature then it is termed as the cold rolled. Department of energy to create breakout steel technologies. The mechanism of positionmode side guide in correcting. The hot strip mill process hsmp is a highspeed, transient metal machining molding process. When the tension control switch to the speed control, to cancel the additional speed. Based on the roll contour, control model, and rolling process, a comprehensive shape control technology is proposed and applied to csp hot. Hot strip mill operations, volume i the making, shaping and treating of steel, 11th edition, flat products volume steels. Steckel mills are the proven solution for coil production up to 1. The hot strip mill of colakoglu metalurji was commissioned in 2010 by sms siemag.
1439 801 855 203 98 1635 937 1625 678 56 1317 531 650 374 1024 1218 1071 456 1652 525 824 249 1144 725 838 1220 1397