Tin Hung Joint Stock Company is providing service system hot dip galvanized at the factory in Cu Chi, Chu Lai and Long Thanh in accordance with the standards: ASTM – A123, A153, – JIS – H8641, – TCVN 5408: 2007 Given the size of many specifications galvanized tanks (up to D = largest 12.5mx 2.0mx R = C = 2.0m)
Centrifugal bath, hot dip galvanizing services Hoang Hung capable of providing services for the hot dip galvanized structural steel product type prefabricated, steel pipes and steel bars, steel components, and products traffic engineering, oil and gas …
Surface treatment prior to embed:
Surface preparation is the most important step in any application method of coating a surface protection. The majority of cases of damage before the expiry date is due to improper surface preparation and inappropriate. The process of preparing the surface of the metal substrate materials for hot dip galvanizing multi-step sequence as cleaning grease … with lye, acid pickling … cleanser removes oxides and prevents oxidation surface again.
Using the pre-treatment tank containing lye, acid or diluted bleach to clean biological contaminants, paint, oil and grease on the metal surface. Substances such as epoxy, plastic vynil, asphalt, welded scrap is not cleaned by chemical processing method as above, shall be processed by methods such as sand blasting or other mechanical methods.
Using sulfuric acid solution or dilute hydrochloric acid at temperatures warm to remove the oxide (rust) on the surface details
This is the final step of the surface treatment stage before being hot-dip galvanized, zinc chloride solution using ammonium with 2 goals. Remove the remaining rust and make up one layer of protection to the surface before the last pickle dip galvanized tank.
Hot dipped galvanized
In this step the material is completely embedded in the molten zinc tank at least 98% pure zinc, zinc chemicals in surface melting is specified by ISO or ASTM (or other equivalent standards). Zinc bath temperature maintained between 435 to 455 degrees C.
The processed products are embedded in the tank long enough to reach the temperature of the bath, the details are taken out of the bath slow and zinc residue is removed by gravity, vibration or centrifugation.
The physical and chemical reactions in the process is still going on when the temperature close to the temperature details bath. The details are cooled with water or air temperature in the environment immediately after taken out of the bath.
Two important properties of hot-dip galvanized layer was carefully considered after plating and coating thickness of the coating bonded. ISO, ASTM (or other equivalent standards) issued minimum standards for coating thickness hot-dip galvanized for all kinds of details in the various fields.
The lifespan of the coating
Life expectancy is defined as the life expectancy until 5% of the surface layer of rust appear. The chart below shows the thickness of the hot-dip galvanized coating to service life when the hot dip galvanizing of steel are used in different environments.