• sale05-China steel building

Hot-dip galvanizing (HDG) is a proven anti-corrosion solution for fabricated steel components such as steel columns, beams, trusses and RHS rectangular hollow sections. After all welding, flame straightening and fabrication work are fully completed, the whole member is immersed in molten zinc at around 450℃. A metallurgically bonded zinc alloy layer forms on the steel surface, providing reliable protection for decades even in coastal and humid environments.

Many clients confuse pre-galvanized coil and hot-dip galvanizing. Pre-galvanized steel is zinc-coated at the coil stage before roll-forming into Z or C purlins. Hot-dip galvanizing applies zinc coating to finished fabricated members.

During HDG production, vent holes must be drilled on closed hollow sections. Trapped air inside RHS will expand when heated, which may cause weld rupture and molten zinc splashing without proper vents. Minor zinc lumps may appear after galvanizing. If grinding removes zinc and exposes base steel, touch-up with zinc-rich paint is required.

During HDG production, vent holes must be drilled on closed hollow sections. Trapped air inside RHS will expand when heated, which may cause weld rupture and molten zinc splashing without proper vents. Minor zinc lumps may appear after galvanizing. If grinding removes zinc and exposes base steel, touch-up with zinc-rich paint is required.