Together
to success
since 1997
INTECH GmbH
We are interested in cooperation with the manufacturers of hot dip galvanizing lines, who are looking for an official and reliable distributor to supply their equipment to the industrial plants in Russia.
The company’s top management and sales team are well acquainted with the Russian market, its mentality and laws; they also understand industrial specifics of the financial and economic activities of the Russian customers. All our sales managers have a large customer database, extensive experience of successful sales and well-established connections with the potential buyers of your hot dip galvanizing plants. This allows our managers to promptly set out the most promising directions for promotion and to ensure a rapid entry of the products into the promising Russian market. Our employees, who are fluent in English and German, are focused on working at the international market with the supplies of foreign equipment.
Our team of experienced engineers, who can handle the most serious technical problems, constantly keeps in touch with the Russian customers, holds meetings and delivers presentations regarding the latest achievements of our manufacturing partners. They point out the engineering challenges and actively communicate with all the departments at Russian plants. That is why the specifics of doing a business in the Russian Federation are well-known to us, and we also know the equipment of the local industrial plants and their up-to-date modernization needs.
Once we become your authorized representative in Russia, our marketing staff will carry out a market research in order to check the demand for hot dip galvanizing lines, will submit a market overview for hot dip galvanizing mechanical equipment that you offer and evaluate the needs for this type of equipment at local plants. Our specialists will also estimate the potential and capacity of this market at local industrial plants. Our IT-team will start developing a website for your products in Russian. Our experts will assess the conformity between your hot dip galvanizing lines and customer needs as well as analyze the common reaction to the new goods in general. We will look into the categories of potential customers, and pick out the largest and the most promising plants.
Upon becoming your authorized agent on the territory of Russia, ‘Intech GmbH’ LLC (ООО «Интех ГмбХ»), will obtain certificates, if required, for a batch of the goods, for various types of hot dip galvanizing lines in compliance with Russian standards. We can also arrange the inspection in order to obtain TR TS 010 and TR TS 012 Certificates. These certificates provides permission to operate your equipment at all industrial plants of the EAEU countries (Russia, Kazakhstan, Belarus, Armenia, Kyrgyzstan), including the hazardous industrial facilities. Our company is eager to assist in issuing Technical Passports for hot dip galvanizing lines as per Russian and other EAEU countries’ requirements.
Our engineering company ‘Intech GmbH’ LLC (ООО «Интех ГмбХ»), collaborates with several Russian design institutes in various industrial segments, which allows us to conduct preliminary design as well as subsequent design works according to the standards, construction rules and regulations that are applicable in Russia and other CIS countries. It also enables us to include your hot dip galvanizing lines into the future projects.
The Company has its own logistics department that can provide packing service, handling as well as the most efficient and cost effective mode of transportation of the goods (incl. over dimensional and overweight goods). The goods can be delivered on DAP or DDP-customer’s warehouse basis in full compliance with all the relevant regulations and requirements that are applicable on the Russian market..
Our company has its own certified specialists who will carry out installation supervision and commissioning of the delivered equipment, as well as further guarantee and post-guarantee maintenance of hot dip galvanizing lines. They will also provide necessary training and guidance for the customer’s personnel.
The galvanizing line consists of baths that provide for preparation of surface before galvanizing, one three-cell drying furnace that dries parts before they get into the galvanizing bath, one galvanizing furnace, one cooling zone, and one control zone.
Like any surface treatment, hot-dip galvanizing requires proper surface preparation to achieve homogeneous iron and zinc reaction when the parts are dipped into the galvanizing bath.
It includes the following steps: degreasing, rinsing, pickling, rinsing, and fluxing.
Degreasing is intended to remove products, and the quality of galvanizing depends on this process in general. Depending on the contaminant, a degreasing agent is selected, which is then used for degreasing at 60 to 80°C. Removal of stains is required before pickling stage to avoid defects of galvanized metal such as, for example, absence or layering of zinc coating.
Rinsing should be carried out effectively; it allows removing fatty substances and foam from the parts after degreasing.
Pickling is a process, in which the metal surface is cleaned by removing an oxide layer formed in the result of heat treatment (scale) or adverse storage conditions (rust).
Pickling is performed using hydrochloric acid with a concentration of 120 to 210 g/l, at ambient temperature (20 - 25°C). The advantage of hydrochloric acid is good solubility of iron chlorides, a clean shiny surface and sufficient penetrating of molten zinc.
It is recommended to add inhibitors to remove only oxides and hydroxyls, limiting the impact on the basic metal and avoiding the risk of hydrogen saturation.
Proper control of the concentration in the bath will allow optimizing the processing quality, costs, emissions and, consequently, protection of the environment. For defective parts, a bath for removing of zinc coating is provided. This bath allows cleaning of parts using spent acid solution.
Pickling is followed by rinsing to neutralize the possible residual traces of acid and salt removal. Using multiple successive rinsing baths will optimize washing and reduce water consumption.
Fluxing serves three purposes:
The flux applied consists of zinc chloride and ammonium chloride.
The processing is performed using a concentrated solution of the flux (400 - 600 g/l) at 60°C.
The solution of the fluxing bath should be monitored from time to time (density, pH, and iron content). Purification is carried out by addition of hydrogen peroxides, which continuously precipitate ferric salts at the bottom of the bath, and then go to the sludge settling and filtration system.
This operation follows fluxing and allows evaporating of moisture from the surface of the parts and hollow elements in order to avoid splashing of zinc with water vapor when the parts are dipped into the furnace and to avoid their deformation. It also allows pre-heating of the parts to approx. 100°C, thus enhancing the galvanizing furnace efficiency, saving energy and reducing the galvanizing cost.
Drying is longer than galvanizing, thus the furnace must have more than one cell (at least 2). The performance taken into account is the maximum load of the furnace.
Loading and unloading devices ensure timely movement of loads and optimal load of the galvanizing furnace.
Upon completion of the previously described operations, one may consider that the contact between the liquid steel and zinc will be provided at the best.
The main parameters of a successful operation:
Zinc melt temperature is 419°C, galvanizing is performed within the classic range of 445 to 460°C, which helps to reduce the formation of matte, oxides, etc.
Exhaust gases are drawn by suction and filtration system, which is in full compliance with environmental regulations.
Dipping phase:
There are several stages during this phase: heat exchanging inside the parts, melting and flux destruction on the surface of the parts, resulting in optimal penetration of molten zinc.
Dipping rate is also an important factor. Too slow dipping will release the steel surface from passivated film with the risk of reoxidation, while too fast dipping will lead to seizure of salt residues from the surface, the flux will not melt, and as a result, it will cause formation of defects.
Dipping time:
Dipping time varies according to the loads (weight, size, shape. By an average, it is 3 to 10 minutes.
Before the parts are withdrawn, one should remove the slag from the melt surface using a scraper to prevent the slag from settling on the parts.
Withdrawal from the bath:
Withdrawal rate affects the final thickness of the resulting coating. It affects the thickness of pure zinc layer (µm) associated with zinc spreading and solidification rate.
The rates are selected based on performance, dipping time and surface quality (smudges, drops), considering adjustment of part tilt in the assembly depending on their geometry.
Cooling takes place outdoors in the area of warehousing and storage combined with quality control site before packaging.
An exhaust gas aspiration system mounted on baths and exhaust casing mounted on the traverse movement will ensure a stable fume exhaust and effectively protect equipment against corrosion, which is caused by vapors of hydrochloric acid. Moreover, filters will provide for cleaning from dust and acid vapors in full compliance with the environmental regulations of the Russian Federation.
A fully automatic transport system integrated into a hot-dip galvanizing line is designed for feeding, unloading and dipping of galvanized parts in accordance with predetermined process parameters. It can be controlled by a remote operator control via a PLC or industrial computer with the software required. Also, the line can be controlled manually.
The main purpose of metal galvanizing is to form a coating that will be impermeable for the surrounding environment and protect the base metal from irreversible corrosion process. Galvanizing of metal surfaces (steel, in particular) is the most effective way to prevent corrosion, as zinc metal has unique chemical properties. Water hardly reacts with zinc. When exposed to the atmosphere, zinc forms an even, stable, and air-impermeable film of zinc oxide (ZnO) and zinc carbonate (ZnCO3), unlike corrosion, which creates a permeable porous structure. As a result the base metal is unprotected, which leads eventually to its total destruction. An additional advantage of zinc is that it has a lower electrochemical potential in comparison to iron. While iron acts as a cathode, zinc functions as an anode in the presence of water; in the result base metal surface (steel) is passivated in a moist environment, and that inhibits oxidation corrosion processes. This property gives zinc undeniable advantages over other ways of steel protection from corrosion. Zinc metal is relatively soft, and even if the protective layer is mechanically damaged, zinc, being an anode in the presence of moisture, “overcoats” the damage occurred and forms a new protective layer.
The following types of galvanizing of steel products exist:
Cold galvanizing by painting is carried out by applying liquid mixture that contains fine zinc powder and the liquid binder onto a steel surface. In this method of galvanizing, the finished surface comprises 89-93% of zinc, and the layer thickness may considerably vary. Cold galvanizing method is not practically feasible and results in a substantial specific consumption of zinc. It is used for galvanizing of steel structures that are already assembled, for restoration of damaged surface of metal products after operation and for single-dip galvanizing of steel products in limited quantities. Due to the porous structure of the zinc layer, additional coating is required.
Zinc metal spraying (gas-thermal spraying of zinc) is carried out by spraying of molten zinc in a stream of hot gas (e.g. air). The molten zinc for spraying is prepared by gas-flame or electric arc process. Like cold galvanizing by painting, the method of gas-thermal spraying is poorly producible and is used to cover large parts and metal structures. The method is not applicable for galvanizing of internal cavities of small diameter and finely-shaped surfaces. The coating thickness is usually greater than 200 µm. Zinc layer has a more secure bond with metal, in comparison to cold galvanizing, but also has a porous structure and requires additional coating.
Zinc electroplating involves immersion of parts to be coated into a solution containing zinc salts under direct current. The steel part is a cathode, and zinc plate is an anode. Zinc electroplating method does not have wide industrial application. Zinc plating thickness is 20 – 30 µm. This method of galvanizing of products’ surfaces is usually used for decorative purposes.
Thermal diffusion galvanizing is carried out in a confined space of a muffle furnace or retort, where galvanized steel parts and zinc powder mixture for thermal diffusion galvanizing are placed. At 400°C - 550°C, zinc mist penetrates into the surface layer of the steel product. In this method, a solid layer of zinc is formed, the thickness of which is determined by the needs of a customer, but it is usually not less than 25 µm. Thermal diffusion galvanizing allows applying of thin coatings onto small metal products with sophisticated configuration, including internal recesses, holes and threads. The disadvantage of this method is the process frequency, that it can be applied to a limited amount of parts, and the production cost of the coating is expensive.
Hot-dip galvanizing is the most high-performance and technologically advanced coating method. The quality of the coating as well as its reliability and durability are significantly higher than other methods of galvanizing. Coating with zinc using hot dip galvanizing is performed by dipping steel products into a bath of molten zinc at 440 - 470°C. The thickness of zinc coating is within the range of 30 - 100 µm. This method is particularly effective in a continuous process, for example, in galvanizing of coiled steel or steel wire. It is also effective in a continuous-batch process involving galvanizing of individual steel parts of 0.5 to 12 meters. Smaller products, such as fasteners, are galvanized by dipping a special drum into a bath with zinc, however, threaded connections require additional machining after galvanizing.
In industrial applications, all these galvanizing methods always have a number of stages:
The last step is optional, but desirable. Zinc is a soft metal, hence application of an additional protective layer increases hardness of the coating and, as a consequence, durability of the protection.
Based on the above, one can conclude that the most effective way to prevent metal corrosion is to galvanize its surface. The method of hot-dip galvanizing is the most technologically advanced process in terms of automation, it provides for perfect coating quality in combination with high productivity and production cost.
Coating the surface of coil steel with zinc (galvanizing) is the most common type of metal corrosion protection. Galvanized sheets may be subjected to bending, stamping, welding, so they are widely used in all industries in the manufacture of general-purpose products (crockery, refrigerators), construction (roofing sheet), agriculture (pipes for irrigation), mechanical engineering (devices, panels, Formed shapes). To improve the corrosion resistance in many cases, galvanized sheets are coated with lacquer and paints (polymers).
Scope of application: coil steel galvanizing.
Specifications:
| Strip movement speed in bath with zinc: | up to 300 m/min |
| Production rate: | 100 – 600 thousand tonnes/year |
| Ingoing material: | Cold rolled strip 0.2-2.5 mm |
Degreasing and annealing of the strip is carried out in the galvanizing line itself.
Finished products:
A thin galvanized sheet used in the production of household appliances, building industry and in a number of other industries (including roll forming, construction metal structures, automotive parts and components of electrical appliances). In addition galvanized sheet can be used for further production of metal with protective paints and coatings. In recent years, these products have become very popular in the steel market of Russia and other CIS countries.
Continuous line of hot-dip galvanizing process consists of the following sections and equipment:
The ENTRY SECTION consists of two alternately operating decoilers (coil weight is 10—40 t), two thickness gauges for measuring strip thickness, double guillotine shears to trim thickened ends of the strip, electric welding machines with straightening rollers for welding overlapping strip ends of two coils, a small loop pit in front of rotary shears to trim side edges, tension rollers and multilevel loop device (storage with strip stock).
Entry section does not operate while strip ends of two rolls are being welded (40-60 s); next sections operate while continuously selecting reserve band from the stock.
Electric welding machine works in an automatic mode during the following operations: centering of ends of two strips, finishing end cutting, end overlapping, gripping, straightening, welding, clamping of joint seal. All power mechanisms are driven by hydraulic cylinders. Thickening of the weld does not exceed 10% of strip thickness; weld strength does not exceed 85% of strength of the base metal strip, which provides for subsequent movement of a strip with tension and at high speed in the line.
A vertical coil feeding unit operates in an automatic mode triggered by the “tracking” system. which checks the strip stock and regulates the strip’s speed in the entry section. A stock end truck moves away from the rope drum that has a direct (gearless) drive from the electric motor, thus ensuring a constant strip tension in all coils with forward and reverse trolley travel.
An electrochemical treatment section consists of baths for electrochemical treatment (degreasing) in alkaline solution, washing and drying chamber and tensioning rollers.
A thermal treatment section consists of a strip tension regulator, nonoxidative heating furnace, cooling jet unit and decay chamber. In the furnace, the strip is heated up to 450-470°C (at this temperature, lubricant residues on the strip surface are burnt).Then the strip is annealed at 730-800°C (for a strip suitable for normal drawing during forging) or normalized at 900-950°C (for a strip intended for deep drawing). Thermal treatment is performed in a protective atmosphere containing 10-15% of hydrogen. It is possible to increase the productivity of thermal treatment (strip speed is up to 15 m/s) through intensifying of direct deoxidizing heating of a strip in the products of incomplete combustion of fuel gas; wherein, in the jet cooling unit, which consists of a fan, water heat exchanger and jet nozzle system for jet preflow to the strip, the subsequent gradual accelerated cooling is applied, and the strip is exposed at about 500°C in the decay chamber.
The GALVANIZING SECTION consists of sloping channel filled with inert gas, bath of molten zinc with submersible equipment (immersion drum, stabilizing and correcting rollers with sleeve bearings). The strip (not in contact with air) goes into the bath of molten zinc (melt temperature is 440-460°C) along the inclined channel at approx. 500°C. The thickness of zinc coating of the strip is controlled by a non-contact jet device. A zinc bath has a ceramic lining or is made of a special alloy; its heating is carried out by removable inductors, burners, immersion ceramic heaters.
The COOLING SECTION comprises a tempering furnace (320-350°С), air cooling chamber of a galvanized strip, and zinc coating thickness gauge.
The STRAIGHTENING AND TEMPER SECTION consists of two temper mills, used to temper-roll the strip, and tension levelling machine. Temper rolling (rolling with a small compression of 0.5-1.5%) and tension levelling are used to improve the quality (flatness) of the strip’s surface, which is necessary for the subsequent application of polymeric coatings. Control of compression level (drawing) is performed using pulse induction sensors and strip tension regulators. Then the strip passes through a passivation bath to fix decorative patterns on the surface ("Zinc Flowers") generated during zinc crystallization in the cooling chamber.
The EXIT SECTION consists of a vertical storage tower, surface quality control system (which includes a control device for the width and penetration defects, radiation thickness gauge, oiling machine for applying a preservative compounds to the strip, end shears, two coilers for coiling of finished strips into coils of a certain weight. Moreover, galvanizing lines can be provided with slitting and shearing lines to produce finished galvanized products in sheets and skelps.
Scope of application:
Hot-dip galvanizing of steel structures is process, in which steel structures, free from oxides and scale, are dipped into molten zinc at 450°C.
The technological process starts when a "rough" metal structure is hung onto a cross-beam at a hydraulic lift. Then it is fed to the chemical pretreatment section where sequentially goes through degreasing, pickling, rinsing and fluxing. Degreasing removes dirt and grease from the surface of the products. Pickling is intended to remove oxides from the surface of metal products, preventing formation of high-quality zinc coatings. Rinsing serves to remove residual acid and iron salts from the surface of metal structures. The purpose of fluxing is to clean the surface of products from iron salts that remain after pickling and that are not completely removed by washing; to dissolve oxides formed on the pickled surface caused by contact with water and air; to clear off melt mirror from zinc oxides at the point where the steel goes out from the hot-dip galvanizing bath. Moreover, it is used to promote penetration of molten zinc to metal surface while reducing its surface’s tension and enhancing physical-mechanical interlocking of iron and zinc. A chemical preparation bath is a metal frame with a hard chemically resistant lining. The lining can be made of different materials ‑ from polypropylene to classical glass. In the modern lines, a protective capsule is set above pre-treatment baths; it removes fumes from the chemical treatment bath (the fumes are then purified in a scrubber) and prevents them from getting into the workshop and environment, thus making galvanizing a more environmentally friendly process. When the capsule is installed, automated telpher pairs operate inside it, so operators do not need to be inside the capsule.
After preconditioning, the cross-beam with the sample is fed into a drying furnace. This furnace is a chamber with circulating hot air. The purpose of the drying furnace is to dry and preheat metal structures. The preheating occurs at 120°C. Drying serves to remove excess water from the flux and to preheat the products prior to galvanizing.
After the drying furnace, the cross-beam with metal structures is moved to the galvanizing furnace where the metal structures are dipped into molten zinc at 450°C. In most cases, a galvanizing furnace is a steel construction with refractory lining and a bath heating system. A galvanizing bath made of Armco-iron is installed inside it. Above the furnace, there is a protective and exhaust duct, which serves to capture the so-called "white smokes" and to protect personnel from possible splashes of zinc. Depending on the layout chosen, the protective and exhaust duct may be either mobile or stationary. After galvanizing, the steel structures are cooled down and, if necessary passivated, and sent to a discharge zone afterwards. In this zone they are removed from the cross-beam.
Galvanizing furnaces differ depending on the type of fuel. Gas heating is the most commonly used, but there are also electrically heated and fueled furnaces. Electric heating is rarely used due to high energy consumption, low profitability in comparison with gas heating, as well as due to the complex heating system. However, in areas with cheaper electricity (for example, close to major power plants), this type of heating can be economically feasible. Furnaces are also rarely used compared to other furnaces.
In turn, gas furnaces are subdivided into flat flame and high speed furnaces. When using flat flame heating, burners are arranged on the bath’s perimeter, and the burner’s flame directly heats the bath’s wall. When using high-speed heating, burners are arranged diagonally, opposite each other and heat the air, which flows around the bath at a high speed, thereby transferring heat. The furnace waste gases are run through special heat exchangers; and this heat is then used for heating of chemical treatment baths or drying furnace.
As for the line’s layout, a classic linear arrangement prevails in the existing lines. According to this arrangement, all the equipment is installed on the same axis in one technological aisle. The cross-beam with the metal structures hung on it is fed to technological aisle on a rail cart. In the technological aisle, all major transport operations are carried out with special chemically resistant overhead cranes with radio control: and the protective and exhaust duct is attached to the double-girder crane. This type of lines became a commonly used design due to their easy installation into existing facilities, i.e. savings in construction work, and ease of operation. According to this layout, a workshop itself with a 30 meter bath is a two-aisle workshop, the width of the aisle is at least 18 meters.
This layout has some modifications. The first modification involves substitution of the furnace crane for a ring monorail with telpher pairs. According to this layout, the traverse moves from the drying furnace to the galvanizing furnace, from the galvanizing furnace to the cooling bath and then it is placed on a cart by telpher pairs that move along the ring monorail. Then, the telpher pair returns to the drying oven. Usually 2-3 telpher pairs are used, which increases the speed of the transport system due to lack of backward movement. It has also become common to use a casing above a pre-treatment area in the in-line layout. Such layout is called semi-automatic, i.e., with automated chemical preparation area.
Recently, a new type has become commonly used, which is an automated type. The main principle of this line is its fully looped flow diagram, where all technological stages are managed by an automated system according to a given galvanizing program. According to this scheme, a person only hangs metal onto a cross-beam, as well as cleans the bath surface during galvanizing. Telpher couples are used instead of overhead cranes automatic. Each telpher pair passes through all stages, from hanging to withdrawing, and returns to the beginning of the process.
Steel wire galvanizing is a widespread and effective way to protect steel from corrosion. Currently, about a third of the total volume of produced wire is coated with zinc.
The most common method to apply zinc coating onto a wire is to galvanize it in melt (hot-dip galvanizing). Wire hot-dip galvanizing lines are characterized by high capacity, high utilization rate of production facilities, and efficiency. The zinc coating obtained by this method has good adhesion to steel.
Galvanizing of wire in molten zinc usually includes all activities that are typical of this process. However, certain operations and regulations depend on the peculiarities of the particular mode of wire galvanizing.
Dip galvanizing process is performed in a single process flow using continuous apparatus and consists of the following operations:
Steel wire galvanizing is usually carried out in molten zinc at 440 to 470°C. The wire through-put rate in the galvanizing bath is 26-40 m/min, and, in some lines, it may reach 50-60 m/min or higher. The melt used can be either pure zinc or Galfan (Zn - 95%; Al - 5%). Basically, a ceramic galvanizing bath is used. Also a steel bath made of Armco-iron can be used, but this option is not suitable for use with Galfan due to high reactivity of aluminum.
State of the art lines for wire hot-dip galvanizing are more similar to continuous steel strip hot-dip galvanizing lines in terms of the composition of the equipment. These lines use furnace annealing / recovery in a protective atmosphere, thus eliminating pickling and fluxing processed, as well as using a second galvanizing bath with molten Galfan.
The technological process of using this line is as follows:
Decoiling → electrolytic degreasing → rinsing → annealing/recovery → cooling → galvanizing → removing galvanizing zinc surplus → cooling → coiling
Upon becoming the official distributer of hot dip galvanizing lines, our company ‘Intech GmbH’ LLC (ООО «Интех ГмбХ»), carries out the following: finds the buyers of your products on the market, conducts technical and commercial negotiations with the customers regarding the supplies of your equipment, concludes contracts. Should a bidding take place, we will collect and prepare all the documents required for the participation, conclude all the necessary contracts for the supply of your equipment, as well as register the goods (hot dip galvanizing plants) and conduct customs clearance procedures. We will also register a certificate of transaction (Passport of Deal) required for all foreign trade contracts in the foreign currency control department of the authorized Russian bank so that currency transaction could be effected. If required, our company will implement an equipment spacing project in order to integrate your equipment into the existing or newly built production plant.
We are convinced that our company ‘Intech GmbH’ LLC (ООО «Интех ГмбХ»), will become your reliable, qualified and efficient partner & distributor in Russia.
We are always open for cooperation, so let’s move forward together!