Galvanization Process: Things Every Engineer Must Know

Galvanization Process: Things Every Engineer Must Know

Galvanization is the practice of immersing clean, oxide-free iron or steel into molten zinc in order to form a zinc coating that is metallurgically bonded to the iron or steel’s surface. This zinc coating protects the surface of the galvanized metal against corrosion, by providing protection to the iron or steel.

Due to the unique corrosion resistance of Zinc, it is the widely used as a sacrificial anode, providing even better protection to the steel that ordinarily painted steel surfaces.

The hot dip The hot dip galvanizing process is adaptable to coating nearly all types of fabricated and non-fabricated products such as wire, tanks, sheets, strip, pipes and The hot dip galvanizing process is adaptable to coating nearly all types of fabricated and non-fabricated products such as wire, tanks, sheets, strip, pipes and tubes, fittings, hardware, wire cloth, hollow-ware, and structural assemblies.

All galvanizing consists of four fundamental steps:

1. Surface preparation
2. Pre-fluxing
3. Galvanizing
4. Finishing

The preparation steps consist of cleaning and pickling operations that free the surface of dirt, grease, rust and scale. It is dipped into a caustic soda to remove oil, grease, paint and other marking. 

An acid solution is used to remove rust. The preflux step serves to dissolve any oxide that may have formed on the iron or steel surface after pickling and prevents further rust from forming. 

Properly Cleaned Steel, hot-dipped in Molten Zinc Bath

Clean, oxide-free work is galvanized by immersion into molten zinc. Finishing operations include quenching, removing excess zinc and inspection.

What a Piping Engineer Need to Know:

Galvanization process, albeit effective in corrosion prevention, raises a big question on joining of galvanized pipe fittings. Butt Welded fittings cannot be galvanized, as this is not good for the welding process; toxic gases will occur with welding.

Galvanized Threaded Pipe fittings

How Do we Join Galvanized Pipe Fittings then?

Galvanized fittings like reducers, elbows are better-off threaded. Using a threaded connection is perfect for joining or connecting galvanized fittings.

Other better ways is by flanged connection (bolts and nuts)

DEP extract for Galvanized Carbon Steel Pipes, #150 ratings.

Generally Piping Engineers should be really careful when dealing with galvanized butt-welded fittings.

Welding post-galvanizing is highly discouraged.

TimmsVille Engineering offers affordable courses for interested candidates requiring these knowledge. We offer both practical, in-depth theoretical training as well as software competence.........See more

Home tutoring is also available.For more enquiries contact:-

E-Mail:- timmsvillee@gmail.com