Difference between BATCH GALVANIZED VS PREGALVANIZED PRODUCTS

There is a general misunderstanding among common people that every zinc coating is called galvanization but this is not true as there might be many processes through which a zing coating can be applied. Hot Dip Galvanizing is a coating which is formed after immersing a steelwork in molten zinc. There are however two different processes of hot-dip galvanizing which are pregalvanizing and batch galvanizing. 

Batch galvanizing is a process that is used to coat fully fabricated items and includes chemical cleaning of work before immersing it in the galvanizing bath. The item gets completely coated including internal surfaces if hollow sections. The thick coating also provides the best level of available corrosion protection. 

Pregalvanization is a process where you take a specific product and galvanize them through an automated process. Steel tubes can be galvanized through an automated process. The immersion time is less and after removal, steam can be blown on the bore of the tube which gives it a good surface finish. In the case of reselling, the tubes can be cut to different sizes which creates uncoated edges. 

Strands of wire can be coated using an automated process. The immersion time is very short and the wiping procedure is used to remove excess zinc and give a smooth finish to the final product. It is better to use a mesh of wires so that thicker galvanized coating can be achieved. The steel sheet is uncoiled and passed through the reduced atmosphere before immersing in galvanizing bath for a brief period. 

Read more: Hot Dipped Galvanizing Services In Vadodara

After withdrawing the sheet from the galvanizing bath a mechanical wiper or air knife is used for removing excessive zinc so that the product has a smooth finish. The sheet after galvanizing is recoiled before the stockholder and then it is uncoiled and cut for sale which produces uncoated edges on the sheet. 

Both batch and pregalvanized coating have different characteristics and some of them are being enlisted below. 

  1. The coating continuity in batch galvanizing is continuous over whole item whereas in pregalvanizing the cut edges are left uncoated 
  2. In batch galvanization, coating formation after galvanization is not recommended as it can damage the product whereas in pregalvanization coating can be normally formed without any damage 
  3. Batch galvanization offers a high level of sacrificial protection whereas a pregalvanized product has less sacrificial protection because of the thin coating due to which rust formation can happen from cut edges of the sheet 
  4. The coating appearance after batch galvanizing can be bright but variable whereas pregalvanized products the overall finish is bright without any variation
  5. There is high resistance to abrasion in batch galvanizing due to thick and hard layer of iron and zinc alloy whereas in pregalvanization the alloy layer is very thin which can cause abrasion easily
  6. The coating thickness in batch galvanizing is very thick as compared to pregalvanized coating
  7. The consideration of design for galvanization is required in both batch and pregalvanized products 

At Tanya Galvanizers, we offer the best hot-dip galvanizing in Vadodara. We offer both batch and pregalvanization and you can choose the one which suits your requirements and falls in your budget.

Importance Of Inspection Of Hot Dip Galvanized Products-Tanya Galvanizers

Importance Of Inspection Of Hot Dip Galvanized Products

In today’s time protection is a must. The surroundings are getting challenging with each passing day. Although, the realization of the protective shield on things that are always exposed to the outer world is from our ancient past. Hence, way back in 17th-century scientist and researchers started their work towards protecting even metals from weathers. One such protection shield found was the process of Galvanizing. One of the best processes on galvanizing is hot-dip method. The hot-dip galvanization is a very popular and successful method.

The purpose of galvanizing was to create a protective shield through zinc coating on steel. The exposure of steel can be up to 200-degree temperature and will still be strong due to galvanizing. Metals have a tendency to get rusted with extensive exposure to weather and hence creating a protective shield is one such critical requirements. As mentioned before hot-dip galvanizing is the preferred method. In this method, coating happens at a temperature of around 449 degrees. At this level of temperature when steel goes through that heat, it also absorbs few properties of zinc, making it stronger.

The process is quite assuring as it sounds and further reassuring on effective inspection. Before the coating, the steel has to be well prepared which decides the future strength of the coating. It is like when you have to polish your shoes you need to first clean them and then polish. In the same way, cleaning of steel is primary for a longer future and ensuring the efforts are worth it. Although, the coating life always depends on the amount of exposure of the metal. One can ascertain these details based on the standards that are available.

While doing inspection there are few things to consider is the uniformity of the coating. When the coating is not done in required temperature many times it has cracks. Also when steel is not cleaned properly it will result in bumps through the metal, which leads to a breakthrough for breaking the shield. Let us list down checkpoints while doing inspection of hot-dip galvanizing.

  • The smoothness of the surface
  • Edges and cuts are well ventilated
  • Overlapping surfaces are well taken care of
  • The thickness of the coating be as defined or required
  • Continuity of the coating
  • Color and uniformity of the coating

The above are the basics of inspecting hot-dip galvanized products. The inspection list can be more extensive with the nature, design and type of the structure that is galvanized. Many time even the purpose of the product plays a significant role in deciding the type of galvanizing especially in products like jewelry and food graded stuff. You can always reach us to know more about the inspection details and the galvanizing process information.

Is Hot-Dipped Galvanized The Same As Galvanized?

Galvanization is the process where steel is coated with corrosion resistant zinc. The zinc coating prevents corrosion and in case the coating is scratched, the steel is still protected. Galvanization does not change mechanical properties of steel.

Hot-dipped galvanizing is oldest and most popular form of galvanization process. Metals can be galvanized in more than one method. In hot dipped galvanizing, clean steel is dipped in molten zinc and a unique coating formation takes place that forms strong bond with the steel.

The protective outer layer is more long lasting and tough than other coatings that bond mechanically or electrically. Hot dipped galvanized makes sure that zinc coating applied to protect steel surface provides extended durability outdoors.

Electroplated galvanized steel is softer as compared to hot dipped galvanized steel, electroplated galvanized steel is prone to scratches, daily wear and tear and rough handling.

Electroplated galvanized steel will last as long as hot dipped galvanized steel if it is being used for organizing socks in your closet. An electroplated galvanized bucket if left outside and face drops, scratches and dings will last than 70 years.

Both galvanizing method and the environment it is being used in test the performance of a galvanized metal. Electrogalvanized coating is made by applying zinc to steel strips and sheets by electrodeposition. The coating thickness is less than hot dip process but gives a smooth finish.

The steel used in car bodies is galvanized through electroplate galvanizing as decorative paint can be easily applied after galvanization. Zinc is electrodeposited to steel by immersing the steel in electrolyte a solution of cyanide or zinc sulfate. Pure zinc coats iron or steel surface through electrolytic action.

Hot Dip Galvanizing Services-Tanya Galvanizers

If an electroplated galvanized finish cuts the steel edges or gets damaged under the zinc layer it is prone to corrosion. Zinc product reacting with oxygen and water or white rust does not occur on smoothly finished galvanized buckets.

The advantages of hot dipped galvanized are thick coatings, corrosion resistant and sacrificial protection of zinc coating. The finished product can be used outdoors in all types of weather conditions. The method is popularly used in construction industry.

Thus, we see that hot dip galvanizing is much better than all types of galvanizing process existing today. We at Tanya Galvanizers provide services in various public sectors and our latest machinery and technology gives you quality products at reasonable price.