Surface defects and their control in hot dip galvanized and. Weight control in continuous galvanizing line akhil p deote1, dr. Csis hotdippedzinc coating capabilities are found in two lines. Continuous hotdip galvanizing line cgl, continuous. Continuous sheet galvanizing american galvanizers association. Sms group cold rolling pickling line tandem cold mill of jsw steel ltd. The steels corrosion resistance makes it ideal for applications such as air conditioning units, air ducts, metal ties, studs, siding, decking, roofing and culvert. Continuous process today, the most common method of hot dip galvanizing steel sheet is on a continuous galvanizing line cgl. Today, the most common method of hotdip galvanizing steel sheet is on a continuous galvanizing line cgl. The coating, which is applied by passing the sheet or strip through a zinc bath at high temperatures, improves the corrosion resistance of the final product. Coating weight model for the continuous hotdip galvanizing process article pdf available in metallurgical and materials transactions b 383. Continuous sheet galvanizing created in 2010, this onepage handout is a comprehensive sidebyside comparison of general batch afterfabrication hotdip galvanizing and prefabricated, continuous galvanized sheet.
Mar 31, 2017 continuous galvanizing is a process in which the surface of a continuous ribbon of steel is coated on both sides with a thin layer of zinc. The characteristic of any process is the transformation from an input to an output. Design and construction must be suitable for galvanizing. Pdf coating weight model for the continuous hotdip. The high speed gasjet discharged from the nozzle slot impinges on the strip, and at this moment, wipes the liquid coating layer dragged by a moving strip. We do this by consolidating what were previously the final five processes in the coldrolling of steel sheets into a single continuous process, shortening operations. Cgl these lines are capable of producing highquality steel sheets. Continuous hotdip galvanizing line cgl, continuous annealing. Continuous galvanizing line cgl the purpose of the continuous galvanizing line cgl is to apply a coat of zinc onto the surface of steel sheets in an effort to increase their corrosion resistance. The oxidized wire surface scale resulting from annealing is removed by. Andritz selas provides galvanizing furnaces cgl with a wide range of heating and cooling technologies to satisfy the process requirements for production of. Modification of passivation unit in continuous galvanizing. Coating processes and surface treatments galvanizing.
The hotdip process changes the mechanical properties of the material by doing continuous annealing in furnace. The all radiant tube art furnace of this cgl has been designed and built by andritz selas and allows the customer a high degree of flexibility due to its special design features. Yogiji digi offer both nofwet flux type continuous hot dip metal coating lines for crhr coils. References corbec, a quebec leader in the field of galvanization for over 40 years. In a horizontal configuration, the galvanizing line is able to produce all softforming grades, from lc to ulc and if steels, most hss grades, and dp products up to mpa tensile strength. The hotdip galvanization of structural steel should be considered in projects featuring exposed components that require longterm protection against the elements. Siber demagmetallverformung, duisburg, west germany abstract hot dip galvanizing of cold rolled steel strip is one of the most important processes for applying a highly corrosion resistant metallic coating. Modification of passivation unit in continuous galvanizing line. What everyone in the hotdip galvanizing industry should know. This continuous furnace heat treatment lowers the stresses introduced during wire drawing and increases the ductility of the continuous galvanizing line. Continuous galvanizing line furnaces andritz group. Two furnace sections of the continuous galvanizing process are studied.
Continuous hot dip galvanizing of steel strip, a highly. Our solution a complete new cold rolling plant, including a coupled pickling line and tandem cold mill pltcm, a continuous annealing line cal and a continuous galvanizing line cgl, to produce high strength automotive plate and advanced steel grades for household appliances. Nsblade advanced air knife for continuous hotdip galvanizing line 1. Most surface defects in galvanized steel sheets occur due to rough or mechanically damaged substrate surface, insufficient cleaning of the substrate or poor bath management and line equipment maintenance. After g lvanizing, when the sheet emerges from the zinc bath, the excess molten zinc on them is wiped off by air or gas jets. Continuous galvanizing line low carbon galvanizing. Continuous annealing lines by primetals technologies. In the continuous galvanizing mode, the coil is directed. The two processing lines were manufactured by a consortium of primetals technologies for the supply of the key equipment, and its associated partners. Coating weight model for the continuous hotdip galvanizing.
The low carbon wire galvanizing process is usually accompanied by inline process annealing. Galvinfonote continuous hotdip galvanizing versus 9. A continuous galvanizing line having an annealing furnace of an all radiant tube heating type includes a moisture removal device, dewpoint meters, outlets through which the atmospheric gas in the furnace is collected and inlets through which the atmospheric gas from which moisture has been removed with the moisture removal device is fed into the furnace, the. In the case of automobile bodies, where additional glossy paint will be applied, a thinner form of galvanizing is applied by electro galvanization. Surface preparation surface preparation is the most important step in the application of any coating. A typical hotdip galvanizing line operates as follows. Flux galvanizing lines were also known as cold galvanizing lines, or wheeling lines the first steel company to use. Galvanizing lines the value of the zinc coating process in combating corrosion of the steel surface has grown to be a product feature demanded in everincreasing quantities. The electro galvanizing line, grows in the face of sophisticated competition is the result of the simplicity of the process and the unique advantages of the coating. As a simple and convenient in line processes, continuous coating can process straight bar or coiltocoil product directly into galvanized bar and offers not only an ease, speed and economy of.
Dec 04, 2017 sms group cold rolling pickling line tandem cold mill of jsw steel ltd. The process of galvanizing steel california steel industries. The hot dip galvanizing process the galvanizing process consists of three basic steps. Continuous galvanizing is a process in which the surface of a continuous ribbon of steel is coated on both sides with a thin layer of zinc. From this point, the coil can take two different paths. Annealing and galvanizing lines from the sms group are characterized in particular by the excellent quality of the end product, high efficiency and economy, as well as enormous capacities. Upon exiting the ufcs, the coil is directed vertically down into an electrically heated hot bridle chamber. We can complete the design, manufacturing, installation guide, technical support and necessary training to meet your different requirements and make more business value for you. In recent years various improvements and new technical solutions have been developed, particularly regarding line concepts, furnace technology, galvanizing. When exposed to the atmosphere, the pure zinc zn reacts with oxygen o 2 to form zinc oxide, which further reacts with carbon.
The continuous galvanizing line cgl n1 of tianjin ansteel tiantie in tianjin has been put in operation in june 2009. Sms group cold rolling pickling line tandem cold mill. Galvinfonote continuous hotdip galvanizing versus 9 general. Its a fascinating process with so much behind the scenes chemistry going on.
Continuous galavanizing process,zinc coating,galvanized coils,furnace,cold rolled coils. Pdf continuous hotdip galvanizing 2016 researchgate. The purpose of the continuous galvanizing line cgl is to apply a coat of zinc onto the surface of steel sheets in an effort to increase their corrosion resistance. The maximum production rate for galvanized product is 85. Good results can be obtained on y if certain precautions are taken. Process parameter optimization for zinc coating weight. The process of hotdip galvanizing results in a metallurgical bond between zinc and steel, with a series of distinct ironzinc alloys.
The cleaner removes mill oils and iron fines before the steel sheet enters the annealing furnace. Figure 1 shows a very simple scheme of a technical process. A coating weight model was developed to describe the pressure and wall shear stress distributions as functions of slot gap d and impingement distance z, for the air knife wiping of the liquid zinc coatings in continuous hot dip galvanizing at ratios of zd. The entry accumulator stores the steel sheet to enable welding and maintaining the continuous process operation. If you ever have the opportunity to visit a galvanizing plant and watch firsthand the hotdip galvanizing process, you would gain a whole new appreciation for the silverlooking poles. Continuous sheet galvanizing is also a hotdip process, but is only applied to steel sheet, strip, and wire. The coating, which is applied by passing the sheet or strip through a zinc bath at high temperatures, improves. This process consists of unwinding coils of cold rolled steel and feeding the sheet continuously through a cleaner, an annealing furnace, and then into a molten zinc bath at speeds up to 600 fpm 200 mpm. The low carbon wire galvanizing process is usually accompanied by in line process annealing. The process parameters of the ufcs are governed by the material quality being treated. Hdg also provides the added benefit of clean and low maintenance finish. As a simple and convenient inline processes, continuous coating can process straight bar or coiltocoil product directly into galvanized bar and offers not only an ease, speed and economy of. Continuous hotdip galvanizing line cgl, continuous annealing and processing line c.
Nov 01, 2017 continuous galavanizing process,zinc coating,galvanized coils,furnace,cold rolled coils. Capable of galvanizing at speeds as high as 600 fpm, the 350,000ton annual capacity is a reflection of the very thin steel produced no thicker than 0. Continuous operation coils to be processed on either galvanizing line are charged, or loaded, onto one of two payoff reels. Any failures or inadequacies in surface preparation will immediately be apparent when the steel is withdrawn. The coating thickness is generally influenced on the flow characteristics of wiping gasjet. China 2010 106 gi ga thyssenkruppsteel usa 2010 gi ga thyssenkruppsteel usa 2010 gi ga union steel south korea 2009 105 gi az. Surface defects and their control in hot dip galvanized. There is a wide range of control of zinc coat thickness, and the galvanized steel sheets are used for a broad range of purposes, including. Galvanizing line with continuous anneal capabilities. Continuous galvanizing process cgl galvanizing education.
Study on the wiping gas jet in continuous galvanizing line. Continuous annealing and galvanizing line furnaces andritz is the only company successfully developing and supplying furnaces for small to large capacity, for construction grade to latest generation of ahss for automotive industry with the two heating processes. In the continuous hotdip galvanizing process, the gasjet wiping is used to control the coating thickness of moving steel strip. Galvanizing is a process for rustproo ng iron and steel by. The continuous galvanizing process used to produce coated steel sheet involves a series of complex steps, one of which is designed to anneal the steel to soften it and make it more formable. The resulting coated steel can be used in much the same way as uncoated. Sms group cold rolling pickling line tandem cold mill of. Galvanizing line with continuous anneal capabilities 2 quench the galvanizing line is able to process coils ranging from 900 to 1850 mm 35 to 73 inches in width, and 0. This model was then used in validation studies in order to predict the coating weight as a function of the.
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