Tanya Galvanizers – Hot Dip Galvanizing

What is Hot Dip Galvanizing?

Hot Dip Galvanizing is a factory controlled metallurgical combination of zinc and steel that provides corrosion resistance in a wide variety of environments. Hot Dip Galvanizing protects steel from corrosion in two ways. It provides cathodic protection and barrier protection.  It is one of the oldest methods of zinc coating which includes the immersion of a fastener in molten zinc by which Tanya Galvanizers provides corrosion protect finish. This zinc coating provides sacrificial protection to the steel. The process of hot-dip galvanizing results in a metallurgical bond between zinc and steel with a series of distinct iron-zinc alloys. The resulting coated steel can be used in much the same way as uncoated. Galvanized steel can be welded. As zinc is more reactive than iron, the zinc galvanized coating corrodes first, protecting the steel substrate.

At Tanya Galvanizers we take care of the Hot Dip Galvanizing method. Here at the Tanya Galvanizers the Hot Dip Galvanizing process starts by carefully cleaning the surface of the steel to prepare it for galvanizing. After cleaning, the parts are dipped in a flux tank containing (typically) an aqueous solution of zinc ammonium chloride or they are fluxed by passing through a layer of molten zinc ammonium chloride floating on the top of the molten zinc. In the galvanizing tank, the parts are completely immersed in a molten bath consisting of a minimum of 98% zinc. After slowly withdrawing the parts from the molten zinc, the fasteners are spun in a centrifuge while the zinc is still liquid to remove excess zinc. The parts are then either air or water cooled to solidify the zinc and to permit handling.

For over 150 years Hot Dip Galvanizing has had a proven track record of protection in a myriad of applications. Hot-dip galvanized steel strip (also sometimes loosely referred to as galvanized iron) is extensively used for applications requiring the strength of steel combined with the resistance to corrosion of zinc. Applications include: roofing and walling, safety barriers, handrails, consumer appliances and automotive body parts. One common use is in metal pails.  Galvanized steel is also used in most heating and cooling duct systems in buildings. The most important method of inspection for galvanized articles is visual. At Tanya Galvanizers variety of simple physical and laboratory tests may be performed for:

  • Thickness
  • Adherence of the coating
  • Uniformity of the coating
  • Appearance

Hot Dip Galvanizing: The best galvanizing method

Hot dip galvanizing or HDG method is one of the most advanced methods of galvanizing used by the galvanizer companies. Besides, it is also a widely used procedure to protect the steel made or iron made metal surfaces from the corrosion. In this method used by the galvanizers, a four layered zinc coating is created electrochemically on a metal surface. Therefore, the iron or steel base is moved across the molten bath of zinc at the temperature of 460˚C. It allows the zinc to create a bond with the iron or steel base at any molecular level.

Additionally, as per the hot dip galvanizing consultant companies; the galvanized coating covers the total surface quite easily, including all the scratched, joints and the holes. Due to its effectiveness and the corrosion resistant properties; nowadays, the hot dip galvanizing process is used widely used in the numerous applications starting from the handrails, automotive body parts, and consumer appliances to walling and roofing. Besides, this HDG method is also used to shield the exterior panels as well as the automotive parts. Usually, this kind of galvanized strips made by various galvanizer companies are used in the cooling and heating duct systems in the buildings as well as in the metal pails.

As per the galvanizer consultant companies, it is completely recyclable with the less energy needed to process this galvanizing method for using to protect the corrosion. So, it can be used as the ultimate material by the galvanizers in order to protect the structures of the parks, airports and the waterways of the various countries and states. Here, in this article, we have put together several advantages of this HDG procedure over the other methods of galvanizing. Read along to know more:

  • According to the hot dip galvanizing consultant companies, this method of galvanizing offers the advantage of having low initial costs over the other techniques of corrosion protection. Besides, this process also includes lesser labor intensive while comparing to the other procedures.
  • The coatings of this process enjoy the expectancy of a much higher life of around 40 years and more even in the severe urban and coastal environments. Additionally, this kind of performance and life expectancy of this process are also easily predictable.
  • In some rare cases, the process of hot dip galvanizing includes a higher initial charge, but then also it is much more cost effective than the other methods of galvanizing as it is more durable along with the little maintenance requirements. As this method provides superior resistance to the mechanical and water damage as well as the abrasion damage during erection, service and transportation.
  • Another important advantage of this method is that it is quite straightforward, closely controllable and simple. Besides, all the coating thicknesses are predictable, easily specifiable and regular. All these features enable this method to be precise during design and usage.

Prashant Galvanizers is one of the reputable galvanizer consultant companies in India who also specializes in the hot dip galvanizing methods.

Hot Dip Galvanizing – An overview

The word ‘galvanizing’ refers broadly to the electro-deposition procedure where any thin layer of any other material is inserted to any item that is made of steel. The core reason of the galvanizing process is to guard the base steel by avoiding the rusting. Though, one of the best galvanizing processes invented by the galvanizer companies does not utilize any kind of electrochemical deposition. This process is known as HDG or hot dip galvanizing.

This type of galvanizers has widely become very popular due to the effectiveness it offers while it comes to the corrosion protection. Actually, in the recent terms, the word ‘galvanizing’ or ‘galvanizers’ is popularly used to mention the process of hot dip galvanizing. In this process, a corrosion resistant four-layer surface or finish is produced on the steel base by using the zinc through the electrochemical procedure. As per the galvanizer consultant companies, commonly iron and steel are passed through any molten bath made of zinc at the temperature of 460˚C in order to protect the metals from corrosion. Among the four layers made up by the hot dip galvanizing consultant companies, the top layer is made of zinc and the underneath three layers are created of zinc-iron alloy. The galvanizer companies use this procedure for all the industrial applications which need the potency of steel while maintaining the resistance to the corrosion.

The method of hot dip galvanizing created by the hot dip galvanizing consultant companies has proved to be much more superior than the other methods like metalizing, paint, electroplate galvanizing or mechanical galvanizing. Besides, this method of galvanizing has come out as one of the most reliable as well as result oriented procedures which meets with all the galvanizing requirements of the clients. Unlike the electroplate method of galvanizing, the process of hot dip galvanizing creates a much durable and thicker coating that makes it very suitable also for the outdoor applications. On another side, the thin coating made by the electroplate galvanizers can be consumed quickly and it results in revealing the steel base of any item to the corrosion.

As mentioned by the galvanizer consultant companies, the hot dip galvanizing leads to the superior protection from any type of rusting or corrosion. The solid zinc-steel alloy layers of the hot dip galvanizing work as an effective barrier. If this barrier gets damaged, then the barrier of zinc works as a sacrificial anode and therefore prevents the corrosion. Additionally, the top most layer of this kind of galvanizing only comprises zinc. So, while it reacts with moisture, oxygen and carbon dioxide presented in the air, it creates a thin but strong film, which is known as zinc patina. It acts as the effective barrier over galvanized zinc coating and guards the item from possible corrosion.

Prashant Galvanizers is one of the reputable galvanizer consultant companies in India which offers manufacturing, installation and consultation services on various kinds of galvanizing procedures including the hot dip galvanizing to the galvanizing, manufacturing and engineering industries.

Surface Preparation for Hot Dip Galvanizing

The method of hot dip galvanizing may differ slightly from one galvanizer to another. But all the galvanizers have to go through the three basic steps of hot dip galvanizing are surface preparation, galvanizing and inspection.

Surface preparation is the most important step in the application of any coating. In most instances incorrect surface preparation is generally the cause of a coating failure before its expected service lifetime. The surface preparation step in the hot dip galvanizing process has its own quality control in that zinc simply are not reacting metallurgically with a steel surface which is not perfectly clean. Any failures in surface preparation will immediately be apparent when the steel is withdrawn from the molten zinc because the unclean areas will remain uncoated. The galvanizer has to take action to correct immediately. This can result in problems in coordinating activity that lead to costly and time-consuming delays, errors, and disputes concerning responsibility and financial liability.

Surface preparation for hot dip galvanizing typically consists of three steps: caustic cleaning, acid pickling and fluxing.

  • Caustic Cleaning – Dirt, paint markings, grease and oil from the metal surface are removed by a hot alkali solution. Epoxies, vinyl, blacktop or welding slag must be removed by sand-blasting, grit-blasting and other mechanical means before galvanizing.
  • Pickling – Scale and rust normally are removed from the steel surface by pickling in a dilute solution of hot sulfuric acid or ambient temperature hydrophobic acid. Surface preparation also can be accomplished using abrasive cleaning as an alternative to or in conjunction with chemical cleaning. Abrasive cleaning is a process whereby sand, metallic shot or grit is propelled against the steel material by air blasts or rapidly rotating wheels.
  • Fluxing – Fluxing is the final surface preparation step in the galvanizing process. Fluxing removes oxides and prevents further oxides from forming on the surface of the metal prior to galvanizing. The method for applying the flux depends upon whether the galvanizer uses the wet or dry hot dip galvanizing process.

Prashant Galvanizer has an experienced team of skilled worker for manufacturing Hot Dip Galvanizing plants. The Galvanizer who is famous in Gujarat as the Galvanizer consultant, provides consulting services to the engineering, galvanizing, and manufacturing industries regarding all phases of hot dip galvanizing.

An Introduction to the Hot Dip Galvanizing Process

Galvanizing was known to the world from the beginning of 17th century. It is essential for iron and steel in protecting their life and utility. Science and technology has developed the process of Hot Dip Galvanizing in the 18th century in USA. The first hot dip galvanized iron sheets were imported to Australia in the 1850s. The molten zinc was found to react with steel to form a metallurgical bonded protective coating that had more durability to any other coatings for atmospheric exposure.

Hot-dip-galvanizing

Hot-dip-galvanizing

The characteristics of the coatings applied by these continuous galvanizing technologies are quite different to those of coatings applied by the traditional batch in galvanizing process.While all early hot dip galvanized items were manufactured by dipping them in batches in a molten zinc bath. Different technologies have been developed to more efficiently apply zinc-based coatings to continuously manufactured products such as wire, sheet and tube.

The main difference in the nature of these galvanized coatings is the time that the steel is immersed in the molten zinc alloy. This time is very short (a few seconds) in continuous galvanizing processes, and much longer (4 to 8 minutes) in the hot dip galvanizing process. The resulting zinc-based coatings produced by these processes are quite different and lesser than hot dip galvanizing in their characteristics and performance.

The hot dip galvanized coating is the result of a metallurgical reaction between the steel and the molten zinc, and this reaction will not occur if the steel’s surface is contaminated with paint, grease, oil or rust.Steel fabrications or sections are delivered to the galvanizing plant. These items may contain steels of differing chemistry and surface condition and may be coated with pre-construction primers or other applied protective coatings, including continuously applied zinc coatings.

For this reason, the pre-treatment of the steel sections or fabrications to remove grease, oil, paint and rust is critical to the successful application of the galvanized coating. Acid pickling is done after degreasing and paint removal. Remaining process go through pre-fluxing, galvanizing and quenching. Inspection and dressing is the final process of hot dip galvanizing.

Check Points for Ideal Galvanizer Supplier

The term ‘galvanizing’ broadly refers to an electro-deposition procedure where a thin layer of another metal is supplemented to an item made of steel. The reason of galvanizing is to defend the base steel by preventing rusting. However, one of the most efficient galvanizing methods does not utilize any electrochemical deposition. It is known as hot dip galvanizing or merely HDG.Galvanizing is one of the most common means of rust prevention and is widely used these days. Since hot-dip galvanizing creates a metallurgical bond between zinc and steel there is no chance of rusting. Hot-dip galvanizing gives you a more uniform coat and you will never have to worry about wear or deterioration. Galvanizing companies usually deal in applications that include automotive body parts, consumer appliances, roofing and walling, metal pails.

There are several points that you may consider while choosing your galvanizer suppliers or galvanizer consultants as a partner.Quality is the most important vital factor for choosing the right galvanizer service provider. Hot dip galvanizing is a specialized process and requires good circumstances and road and rail network. A company that meets these provisions and that too adhering to the highest quality standards must be chosen. Galvanizer suppliers must own the essential knowledge in meeting customers’outlook. Experienced galvanizer suppliers like Prashant galvanizer would be able to perfectly assess your requirements and offer their services in helpful way.

Galvanizer suppliers or galvanizer consultants have dedicated themselves to do their bit to save this planet in order to make surrounding pollution free. For this they use environmentally-suitable, no-lead zinc bath besides adhering to the international standards for environment management. Your choice of a hot dip galvanizing company may also depend on the value extra services that are provided along with the main service. This usually includes additional surface preparation, installations, and assembly operations. Capacity is significant to assess the material handling capacity of the Galvanizer consultant before finalizing any one of them because industrial applications could vary in scale, choose a group with one of the largest material handling capacities both in terms of overall lengths and overall weight. Experienced Staff in a company should have the necessary know-how as an industrial galvanizer.Choosing the correct galvanizing service provider is critical to the success of your industrial application as well as environmental conservation. It is advisable to investigate well before zeroing in on an exacting galvanizing company. Employee security and Health Program is significant to choose a company as that shows the dedication and care of the company to keep its employees safe.

Manufacturing Process of Hot Dip Galvanizing

The manufacturing process of hot dip galvanizing may vary slightly from plant to plant. The fundamental steps in the galvanizing process in nutshell can be described as under:

The steel articles are dipped into a hot alkaline solution or caustic soda solution to remove dirt, oil, grease, shop oil, and soluble markings for decreasing and caustic cleaning. The article is dipped in rinsing tank containing clean water for cleaning.

Galvanizing-Process

Galvanizing-Process

Second pickling is performed in second pickling tank which contains dilute solution of either hydrochloric or sulfuric acid 10-32% to remove surface rust and mill scale to provide a chemically clean metallic surface. The same article is again washed in rinsing tank containing clean water.The article is then preserved in pickling tank containing dilute solution of either hydrochloric or sulfuric acid 10-12% for first pickling.

Next step is Flux heating system where the steel is dipped in fluxing tank containing usually a zinc ammonium chloride solution to remove oxides and to prevent oxidation prior to dipping into the bath of molten zinc. In the dry galvanizing process, the item is separately dipped in a liquid flux bath, removed, allowed to dry, and then galvanized. In the wet galvanizing process, the flux floats atop the molten zinc and the item passes through the flux immediately prior to galvanizing.

The article is immersed in a bath of molten zinc of 435 to 455 degree Celsius. During galvanizing, the zinc metallurgically bonds to the steel, creating a series of highly abrasion-resistant zinc-iron alloy layers, commonly topped by a layer of impact-resistant pure zinc.

After the steel is withdrawn from the galvanizing bath, excess zinc is removed by draining, vibrating. The galvanized item is then air-cooled or quenched in liquid.

The most important part of hot dip galvanizing shows the value of experience is flux heating system. An experienced and noted hot dip galvanizing consultant in Gujarat Prashant Galvanizers supply Online Flux Filter System that eliminates production downtime. It eliminates or reduces iron content to a minimum in the flux solution which reduces Dross formation in zinc bath. Using Flux Heating system and Online Flux Filter system, zinc consumption is reduced anywhere from 1-2 kg per metric.

The material is due for dispatch after “Passivation” and inspection formalities. Coating-thickness and surface-condition inspections complete the process of hot dip galvanizing.

Hot-Dip Galvanizing In Gujarat

Galvanization is the process of applying a protective zinc coating to steel, aluminum and iron, in order to prevent rusting. The term Galvanization is derived from the name of Italian scientist Luigi Galvani. Although galvanization can be done with electrochemical and electro-deposition processes but the most common and popular method in present time is Hot Dip galvanizing, in which steel parts are submerged in a solution of molten zinc.

Process of coating of thin layer of zinc on iron, steel and aluminum at a temperature of about 860 °F (460 °C) by a bath of molten zinc is called Hot Dip Galvanizing. It is a form of galvanization. Oxygen (O2) in the atmosphere reacts with the pure zinc (Zn) to form zinc oxide (ZnO), which forms zinc carbonate (ZnCO3) by reacting with carbon dioxide (CO2) of the atmosphere. Generally it looks dull gray and in many circumstances it stops further corrosion, protects the galvanized material from the effects of outside elements. Rust resistance is the main cause of widely use of steel, and can be recognized by spangles on the surface (The size of crystallites in galvanized coatings is a visual feature, known as spangle).

Hot Dip Galvanizing is a factory controlled metallurgical combination of zinc and steel that provides corrosion resistance in a wide variety of environments. Hot Dip Galvanizing protects steel from corrosion in two ways. It provides cathodic protection and barrier protection.

Cathodic protection is commonly applied to a coated structure to provide corrosion control to areas where the coating may be damaged.  It may be applied to existing structures to prolong their life.

Barrier protection is commonly applied to a Hot Dip Galvanizing done surface to protect structure from germs in air or water, which prolongs its life and sustainability.

Prashant Galvanizers expertise of nearly 15 years in galvanizing contractor, manufacturer and supplier of India have an experienced and proficient technicians working team for manufacturing Hot Dip Galvanizing plants. They undertake any kind of critical job like tower line angle, channel and pipe of Shipyard Company, fabrication of tower-line, etc.

Most important and notable fact for Prashant Galvanizers is their un-imaginable capability of manufacturing of automatic/manual galvanizing plant system or 2-in-1 hot dip galvanizing plant system. They have earned a name and fame in a short time among the Galvanizers Consultant in India.