There are many who would like to know the type of kind of surface preparation of iron and steel is required before it is delivered at any hot dip galvanizing plant. For protective coatings, few of the specifications include Preparation for hot dip galvanizing before coating inspection and application requirements after and during coating application. Usually, for galvanizing, no special preparation is necessary. Speaking with the reputed hot dip galvanizing services can help the person to make a huge difference to the knowledge gained about the same.
For the batch hot dip galvanizing, ASTM specifications are arranged differently. A153/A153M and ASTM A123/A123M are some of the commonly utilized specifications for Preparation for hot dip galvanizing. They cover all the inspection need of finished galvanized product. ASTM A385/A385M, A384/A384M and A143/A143M are said to discuss on fabrication process for steel that are to be hot dip galvanized. They also can address few of the surface preparation recommendations before galvanizing.
It is a simple process that batch hot dip galvanizers tend to involve for preparing iron and steel before galvanizing. Once inspection of steel is completed for ensuring presence of adequate drain holes and vent, it gets dipped into cleaning chemical series. The initial chemical is stated to be a degreasing bath to remove organic contaminant like grease, oil and dirt from metal. Pickling acid is the next type of chemical that is used to eliminate rust (oxides) and mill scale from steel. The final step involved prior to galvanizing is to dip the iron or steel into the flux bath. This is to avoid metal oxidization before entering galvanizing bath, as well as to help galvanizing reaction to develop hot dip galvanized coating.
There are not required any specific parameters for ASTM specifications to clean chemicals that are used within the galvanizing process. General concentration tends to make the chemicals quite effective and every galvanizer does optimize its cleaning chemicals, thus providing them with fabulous results to clean the iron or steel. This way, superior quality galvanized hot dip coating is achieved.
Few materials which cannot be removed by the cleaning chemicals
Several materials do make use of chemical chemicals before the galvanizing process. They may not be able to remove or face difficulty in removing. List of common materials:
- Anti-splatter and weld splatter
- Weld slag as well as welding flux residues
- Burrs (may include those excessive rough edges derived from flame cutting)
- Heavy or probably extremely adherent type of mill scale
- Asphalt, vinyls, epoxies
- Mill coatings like lacquers or varnishes present on several pipe types
- Sand, other impurities present on castings
- Crayon markers
- Markers and oil based paints
- Thick or heavy grease or wax deposits
Such materials are to be eliminated from the metal before it is delivered to galvanizing plant. There are present some commonly used standards to ensure abrasive blast cleaning, powertool cleaning and hand cleaning. These cleaning methods and the hot dip galvanizing services offered are considered to be effective enough to remove these materials. Usually, abrasive blasting is required on castings for removing sand including other impurities from casting process. Moreover, different types of products could be used on iron or steel that is considered to be compatible with hot dip galvanizing method for reducing the requirements for hand or power tool cleaning or blasting.