ZINC plays an important role in continuous hot-dip galvanizing. Using the correctly specified grade of ZINC, continuous galvanizing grade (CGG) alloy, or master alloy is key to producing a galvanized product.
ZINC Coatings on Steel
One of the biggest uses of ZINC is in making protective coatings for steel. The development of the wide range of ZINC coatings arose from two happy accidents of chemistry, the relatively slow and predictable rate of atmospheric corrosion of ZINC compared with steel, and the relative positions of ZINC and iron in the electrochemical series.
ZINC will corrode preferentially to give cathodic protection to iron when both are in contact in an aqueous medium. This is used to good effect to protect immersed structures such as ships’ hulls, drilling rigs and pipelines. It also means that any bare areas in a ZINC coating on steel, caused by damage or operations such as cutting or drilling, are still protected by the surrounding ZINC.
Other ZINC Coatings
Originally, ZINC coatings were applied by hot dip galvanizing. This involves dipping prepared steel in molten ZINC. This was done mainly with fabricated steel or with sheets of steel, many of which were profiled to produce the ubiquitous ‘corrugated iron’. The first development from this was the production of continuous strip steel with a galvanized coating. Refinements of this process today account for the greatest part of the total tonnage of steel carrying ZINC coatings.
Standard Specification for ZINC
Specifies the chemical requirements and other delivery conditions for 5 ZINC grades, including Special High Grade (SHG), High Grade (HG), and Prime Western Grade (PW). These grades, and scores of nonstandard variations of them, were once all that were available for use by the continuous galvanizing industry. Some are still employed in certain instances, e.g., SHG (99.990% Zn) is used to reduce the aluminum content in coating line zinc baths. The grades in this standard are also used in the general galvanizing and ZINC die-casting industries.
ZINC INGOTS
Application
Mainly used for die-casting alloy battery industry.
Widely used in Painting / Printing / Dyeing / pharmaceutical / rubber industry etc
Chemical industries, ZINC and other metal alloy plating coating industry.
In ZINC plating, manufacture of brass, manganese bronze, galvanized iron, dry battery; as catalyst and reducing agent.
Specifications
ZINC Ingot 99.995 High quality special high grade ZINC Ingots
Zn (purity): 98.7%-99.995%
Durability
Resistant to abrasion
Corrosion free
Impact resistance
