The material is gradually fed through the furnace with the help of the water cooled beams which lift. Modeling of steel slab reheating process in a walking beam. Improving the through furnace accuracy of slab temperature prediction and optimizing pacing in reheating furnaces of a hot strip mill. Reheating furnace for billets, round bars, blooms, slabs, placed at the head of the hot rolling mill process. Included here are a number of cooled elements as well as special alloy parts that withstand high temperatures and mechanical stresses. The furnace was simplified as rectangular shape and a slab of infinite length was fed into the furnace with a constant velocity. General walking beam and walking hearth furnace systems flexible, high production systems for symmetrical and nonsymmetrical parts caneng roller walking beam walking hearth furnace systems are capable of processing both symmetrical and nonsymmetrical parts at a capacity up to 65 metric tonshr 140,000 lbshr.
Introduction the heat furnaces used for heating the charge are. Efficient energy optimization in reheating furnaces 19 product, yield, energy consumption, pollution and the economics of the product. The furnace is capable of reheating about 800 tons of. General walking beam and walking hearth furnace systems.
Double walking beam furnaces are being heated increasingly by recuperation burners in addition to hot air burners. Department of mechanical engineering, jmit radaur abstract. Research scholar under graduate department of mechanical engineering, jmit radaur er. China walking beam reheating furnace china furnace. Billet reheating furnace, rolling mill furnace, pusher. Modeling of the slab heating process in a walking beam. Energy saving in walking beam furnaces by a new concept. They handle billets, heavy blooms, slabs, and beam blanks. Energy efficiency analysis of an industrial reheating. By using the inverse method, the transient temperature and heat flux was firstly determined on the surface of the steel. Energy saving and environmental impact decreasing in a walking beam reheating furnace c. The temperature in a walking beam furnace can normally reach up to 1,200c. A walking beam furnace main purpose is to reheat semifinished casting products such as slabs, billets and blooms to a homogeneous temperature before they are received by the hot rolling mill. When the beams move upward, the item lying on the stationary hearth of the furnace is raised, and when the beams subsequently move in the horizontal plane through the furnace, the item is displaced, or walked, a fixed distance along with the beams.
The reheating furnace is walking beam type and uses mixed gas for fuel and indirect water cooling system for cooling skids, charging rollers and doors. Sectional drawing showing a modern walking beam furnace. The furnace is divided into three zones preheating, heating. In the metallurgical industry, walking beam type reheat furnaces are one of widely used equipment for slab or billet heat treatment. It is classified as walking beam heating furnace and walking bottom heating furnace.
However the models for heat transfer phenomena are generally valid and may only need a minor adaptation for use at other reheating processes. This paper present the mathematical model of reheating furnace walking beam type using system identification method to estimate the parameter of the. Rolling temperature can be different for different grade of raw material, steel or. The further presented models consider primarily the reheating of slabs in walking beam or pushertype furnaces. The charge could be in the form of billets, blooms, slabs or ingots. Burners portfolio includes 12 different burners types from 0,15 to 7,5 mw. Figure 2 depicts the appearing heat flow rates of re heating slabs in a walking beam furnace. Burners are perceived as the quality factor of the reheating furnaces, therefore italimpianti develops internally and produces the burners for its furnaces. A feasibility to electrify the combustion heated walking beam. Each zone has two thermocouples to measure the average temperature. In modern walking beam reheating furnaces, semifinished products such as slabsbloomsbillets are uniformly heated to a desired temperature and have minimized skid marks. Available in both alloy post and beam walking beam and water cooled refractory beam walking hearth designs, caneng continues to be a leader in walking beam walking hearth furnaces for over 50 years. Pdf on control structure design for a walking beam furnace.
Implementation of models for reheating processes in industrial. The case of multiple parallel continuous walking beam reheating furnace was considered in, in which the scheduling task was to assign slabs to each reheating furnace, sequence slab sequence for each reheating furnace and determine the feedin and residence time of each slab so as to reduce unnecessary energy consumption. Re heating furnace are used for reheating of billets. Jan 22, 2015 draft working on walking beam furnace. Double walking beam furnaces are being heated increasingly by recuperation burners in addition to hotair burners. The further presented models consider primarily the reheating of.
Threedimensional analysis is performed for the turbulent reactive flow and radiative heat transfer in the walking beam type slab reheating furnace by fluent. Pdf modeling of steel slab reheating process in a walking. The 2d heat transfer model utilizes the heat transfer coefficients derived from a 3d reheating furnace cfd model which was validated by using. Walking beam walking hearth continuous recirculating bogie furnaces rotary hearth furnaces mode of heat transfer radiation open fire place convection heated through medium mode of waste heat recovery recuperative regenerative 2. Apr 29, 2016 construction of our new walking beam furnace at the hot strip mill. A simplified practical model for a walking beam type reheat. The typical loading in a forging furnace is 5 to 6 tonnes with the furnace operating for 16 to 18 hours daily. China walking beam reheating furnace, find details about china furnace, industrial furnace from walking beam reheating furnace nanjing nianda furnace science and technology co. The reheating furnace in general is a furnace used in hot rolling mills to heat the raw material. The furnace loses heat to the cooling water of the skid pipe system. Electric, gas or oil fired walkingbeam furnaces pdf fk. Twolayer linear mpc approach aimed at walking beam billets.
Typically the reheat furnace is a refractory lined steel shell, with burners located along the furnace length to provide the necessary heat input. Reheat furnace, mathematical model, heat transfer, walking beam. This allows shorter stock heating times and furnace lengths and thus better control of heating rates, uniform stock discharge temperatures and operational flexibility. The 2d heat transfer model utilizes the heat transfer coefficients derived from a 3d reheating furnace cfd model which was validated by using mill instrumented slab trials. Common to all furnaces is high costeffectiveness that results from constant improvement, quality consciousness, and. A numerical analysis of slab heating characteristics in a. Pdf slab reheating is a very important step in steel product manufacturing. A walking beam reheating furnace is usually dividedlevel 2 determines the temperature set points for. How can the hot material be detected under these extreme conditions. Our walking beam furnace design combines the latest advancements in hot rider and skid system technology, process control and level. Usually, the fuel of the furnace is gaseous fuel, natural gas, heavy oil or pulverized coal, some burning lump coal, etc. The walking furnace is equipped with air recuperators, for waste gas heat recovery from flue gas, which pre. A new methodology involving the integration of a threedimensional 3d computational fluid dynamics cfd model and a twodimensional 2d heat transfer model for the study of the slab reheating process in a walking beam reheating furnace has been proposed.
With more than 145 years of expertise in thermal applications, fives offers flexible reheating solutions that can be customized according to the application. Nov 04, 2018 the reheating furnace in general is a furnace used in hot rolling mills to heat the raw material. Walking beam furnace walking hearth furnace examples of different beam cross sections. Which can be bloom, billet, slab, ingot to rolling temperature. Furnace slab extractors in place of furnace dropout chutes for reduced equipment damage and slab defects. Walking beam furnaces are used for heating slabs, billets, or rods prior to the rolling process. Measurement o f purdue university calumet 2200 169th street, hammond, in 46323 2199892765 the problem the reheating of steel slabs is a widely used process in steel mills and is aimed at elevating the slab temperature. Metallurgy industries often use steel billets, at a proper temperature, to achieve the desired metallurgical, mechanical, and dimensional properties of manufactured products. In modern walking beam reheating furnaces, semifinished products such as slabsbloomsbillets are uniformly heated to a. Ati flat rolled products, a subsidiary of allegheny technologies incorporated ati, one of the most diversified specialty materials and components producers in the world and fives, an international engineering group, commissioned new reheating furnaces for the worlds most powerful hot strip mill. New skid buttons with ceramic composite metal for slab reheating. A simplified burner is validated against the results of the actual burner with the detailed grid resolution to avoid an excessive number of grids. A paradigm for the scheduling of a continuous walking beam reheat furnace using a modified genetic algorithm jonathan s.
Temperature control for reheating furnace walking hearth type. A model for inverse heat conduction is employed to calculate the local surface temperature and heat flux on top of the growing oxide scale layer on a slab moving through a walking beam reheating furnace. Also, kim 1 developed a heat transfer model to analyze the transient heating of a slab in a directfired walking beam type reheating furnace by the finite. Specific fuel consumption depends upon the type of material and number of reheatsrequired. The influence of oxide scale on heat transfer during. Walking beam furnaces our walking beam furnace is mainly used within the steel industry for applications like annealing, forging, heating, stress relieving, quenching and tempering with a maximum operating temperature of 1100c. Fives furnaces for the worlds most powerful hotstrip. Our walking beam furnace design combines the latest advancements in hot rider and skid system technology, process control and level 2 automation as well as advanced burner technology. A paradigm for the scheduling of a continuous walking beam reheat furnace. Withstand action of molten metal slag, glass, hot gases, etc withstand load at service conditions 1 section 1. Reheating furnace in steel plants reheating furnaces are used in hot rolling. Furnace systems for the carbon steel industry moving ahead with experience and innovation on account of its long tradition and experience, andritz maerz a company belonging to the business area metals is one of the leading suppliers of engineering, knowhow, and process technology to the reheating, heat treatment, melting, and refining of.
We have the knowhow and experience to provide reheat furnaces that optimize quality and productivity for processing slabs, billets, blooms and beam blanks. In double walking beam furnaces, the material is heated to temperatures of up to 1,150 c. The furnace is used to reheat slabs of steel approximately 9. Nonlinear model predictive control mpc for slab reheating furnace based on. Pdf fast dynamic heat and mass balance model of walking beam. Tenova italimpianti walking beam furnaces are suitable for heavy plates and heavy loads, especially if quenching is required. Furthermore, due to the sophisticated combustion system, all our walking beam furnaces are highly flexible.
Billet reheating furnace, rolling mill furnace, pusher type. Walking beam furnaces for flat products tenova has installed some of the worlds largest walking beam reheating furnaces for a variety of applications. On control structure design for a walking beam furnace diva. Pdf modeling of steel slab reheating process in a walking beam. Charging may be done as cold charging or hot charging. How to know refractories used in reheating furnace quora. Refractories for reheating and heat treatment furnaces. A paradigm for the scheduling of a continuous walking beam. Twolayer linear mpc approach aimed at walking beam billets reheating furnace optimization. Reheat furnace, pusher furnace top fired, walking hearth. Integrated scheduling of reheating furnace and hot rolling. Optimal operation of steel billet reheating furnaces requires the minimization of fuel consumption while maintaining a homogeneous material thermal soak.
The type of furnace could be pusher, walking hearth or walking beam either top fired or top and bottom fired. Coal or electricity can be used in reheating furnaces. Tenova core is a leading provider of reheating furnaces for a variety of applications. The operations of walking beam reheating furnaces are computerized control using plcdcs systems along with level 2 systems to achieve higher energy efficiencies and to have plan view rolling. Pdf temperature control for reheating furnace walking hearth type. Caneng roller walking beam walking hearth furnace systems are capable of processing both symmetrical and nonsymmetrical parts at a capacity up to 65 metric tonshr 140,000 lbshr. Comparisons of different heat transfer models of a walking. Construction of our new walking beam furnace at the hot strip mill. Walking beam furnaces 20 walking hearth furnaces 24 pusher furnaces 26. The purpose of a slab reheating furnace is to heat steel slabs to a suitable temperature profile around 1250c before entering to hot rolling phase. Installation of new 3,000,000 lb walking beam gas fired reheat furnace consisting of over 12,000 individual pieces. Energy saving and environmental impact decreasing in a.
Quaker introduced quintoplex, a fireresistant grease they had developed for a mining. The goods which are to be heated are moved inside a walking beam furnace. In this paper, a comprehensive twodimensional 2d numerical heat transfer model for slab reheating in a walking beam furnace was developed using the finite difference method. Ingener products reheating walking hearthbeam furnace.
Implementation of models for reheating processes in. Its the typical longitudinal, large furnace which continuously reheats semi. This type heating furnace is used for large slab and shaped blank heating with advantages of huge capacity, no black print on the slab and blank, and timing heating exactly. Reheating furnace is the heart of any hot rolling mill where in the charge is heated to rolling temperature.
In this case we consider all system is the steady state flow process. The walking beam reheating furnace consists of a heating furnace body, a cooling system, a combustion system, an inlet and outlet, a smoke exhaust system, a preheating recovery system, and an automatic control system. Walking hearth furnace article about walking hearth furnace. Schematic of an industrial walking beam furnace with the monitored sensors moreover, there are pressure sensors in recuperative zone for sensing the furnace pressure. On the thermal behavior of the slab in a reheating furnace.
Walking beam slab reheat furnaces in place of pusher furnaces for improved slab heating and reduced slab skid marks. The aim of this paper is to analyze the recuperative burner and regenerative burner for various types of reheating furnaces in steel plant. Top and bottomfired walkingbeam furnaces ensure high production rates and excellent quality steel grades. Walking beam walking hearth continuous recirculating bogie furnaces. The walking hearth beam furnace is based on a system of movable walking beams of refractory or water cooled pipes which by means of mechanic frames make the products to go upward and forward into the furnace to the discharge side.
C hi rag arya research scholar under graduate department. However the models for heat transfer phenomena are generally valid and may only need a minor adaptation for use at other reheating. Over the years many important hot strip mill innovations have been developed, a selection of which is listed below. Here we emphatically introduce the continuous walking beam heating furnace. Kim and huh, carried out an analysis for turbulent reactive flow and radiative heat transfer on the actual shape of a walking beam type reheating furnace by using fluent. Heat treatment temperature of the reheating furnace is not high, generally its service temperature is lower than 0 for reheating furnace lining, usually we use alsi refractory materials which contains alumina 3675%. The furnace is capable of reheating about 800 tons of steel to 2,400 degrees f per hour. In this study, the operation of a reheating furnace is modeled as a. Energy saving in walking beam furnaces by a new concept for skid.
New walking beam furnaces for oil, gas and electric heating. Tenova includes in its references some of the largest installations such as the longest roller hearth furnace ever built 1,000 feet, walking beam furnaces with capacity of 500 tonhour, rotary hearth furnace with a diameter of 170 feet and the largest bloom reheat furnace 150 feet long, 50 feet wide. The walking hearthbeam furnace is based on a system of movable walking beams of refractory or water cooled pipes which by means of mechanic frames make the products to go upward and forward into the furnace to the discharge side. Modeling of steel slab reheating process in a walking beam reheating furnace. The predicted temperature distribution in the furnace and global energy flow fractions are. Reheating furnace is the first step in a hot rolling process. Isncesr16 energy conservation measures in pushertype. The total operating cycle can be divided into i heatup time ii soaking time and iii forging time. We offer reheating furnaces for hot formed materials, furnaces in casting and rolling lines for thin slabs and heat treatment plants for heavy plates and forged products.
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