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 Any failures in surface preparation will immediately be apparent when the steel is withdrawn from the molten zinc because the unclean areas will remain uncoated.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.



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.