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HOT-DIP GALVANIZING PROCESS

Why Galvanize


Galvanizing provides the longest lasting, lowest maintenance, highest value coating available. Not only does galvanizing provide superior corrosion protection through a metallurgically bonded finish, but maintenance costs are also reduced and environmental impact over the life of the product is significantly lower.


Further, the closed-loop galvanizing system is contained and allows for the recycling of waste materials, making the process more efficient and environmentally sound.



Inspection

All steel that arrives at our plants is subject to a thorough inspection for proper drainage, venting and hooking requirements.


Surface Preparation

Surface preparation is a critical step in any coating application. In many cases, coatings failures are due to improper surface preparation. Inadequate surface preparation is of the utmost importance in hot dip galvanizing because zinc will not react with an improperly prepared steel surface and the unclean areas will remain uncoated.


There are 3 steps in the Surface preparation process.


Cleaning (Degreasing)

The first part of the process begins with a complete immersion in a caustic solution to remove contaminants such as organic compounds and dirt.


Pickling

Next the steel is immersed in an ambient temperature acid pickling solution (hydrochloric acid), which removes rust or scale. The steel is then rinsed to remove all traces of the pickling solution.


Fluxing

Fluxing in an aqueous solution of zinc-ammonium chloride is the final surface preparation step to remove oxides and prevent further oxides from forming on the surface prior to galvanizing to promote intermetallic development.


Galvanizing

Hot-dip galvanizing

The steel is submerged in a bath of molten zinc until it reaches 840° F (450° C). At this point, the zinc reacts with the steel to form zinc/iron intermetallic layers on all surfaces inside and out. Unlike paint, which is a surface coating, the zinc forms a bond with the steel.


Quenching (Passivation)

The articles are cooled by either water or ambient air immediately after withdrawal from the bath. This prevents the metallurgical reaction from continuing after the materials are withdrawn from the bath, which can lead to quality issues.


Finishing/Inspection

The galvanized steel is weighed and carefully inspected. Products are closely examined for coating thickness and coating appearance. Calibrated instrumentation ensures quality standards are met and in compliance with applicable ASTM specifications.


The Hot-dip galvanizing process steps
The Hot-dip galvanizing process

Quality Assurance


Quality Assurance is not just a buzz word for our process and quality personnel. Our galvanizing and inspection personnel are expertly trained to ensure the galvanizing processes meet not only the industry standards, but the Corbec standards as well. Our plants are held to the highest standards for quality control to ensure we deliver a finished product of the highest quality.