Hot-dip galvanization is a modern trend in the anti-corrosion treatment of steel. It offers many advantages over other anti-corrosion methods, such as:
Long lasting steel protection
Not expensive
Steady alloy coating
Protective coating on all outer, inner, as well as hard-to-access surfaces, including edges.
Possibility of paint application (duplex system)
Reliability and resistance
Resistance against mechanical damage
Environmentally friendly

Our galvanization vat dimensions:

L — 7.000 mm
l — 1.500 mm
h — 2.400 mm

Monthly production capacity: 700–1.000 tons

The technology of hot-dip galvanization

When immersing a component into zinc melt with a temperature of 450–460°C, not only does there develop a cover of the zinc on the steel, as in other surface treatments, but metallic phases of iron and zinc with high hardness and resistance against abrasion also form.

The thickness of the coating created is usually 50–190 microns, depending on the chemical composition and type of material.

Technological Openings

Hot-dip galvanizing of hollow structures cannot be done without technological openings, because of the explosion hazard. It is imperative that the hollow spaces have sufficiently large inlet openings and vents. Their number and size also significantly affects the quality of the surface finish.

Individual components must also have holes for hanging. Mounting holes below 8 mm can be flooded after galvanizing. 
For larger holes it is necessary to add due to the thickness of the material. Threads need to be cleaned or protected from the zinc.

You will be noticed about the insufficient quantity of or inappropriately placed openings when we take over the order. You can solve these issues yourself or the technological openings can be made by our staff. This service will be based on an hourly rate and credited to the contract price.

Technical recommendations

The chemical composition, surface, weight, grade, thickness and roughness of the base material will affect the appearance, the deposit and the structure of the zinc coating.

We do not recommend assembled structure components. Assembled structure components pose problems both for galvanizing and transportation. The galvanizing of flat structure components is of better quality and is more economical.

Prevent deformation. Think about the possibility of the expansion of material and asymmetrical cross-sections.

Beware of “dead” corners and angles. Ensure radiuses and holes in the bulkheads. For framed structures of open profiles pay attention to ventilation and drainage openings.

Don’t forget about inlet and outlet openings. Because of the danger of an explosion it is necessary that hollow structures be provided with inlet and outlet openings. Their arrangement and size affect the quality of the hot-dip galvanizing.

Allow hanging. We recommend placing the inlet and outlet openings in a vertical position to the hanging openings.

Beware!

Improperly designed parts can collect flux residues and zinc ashes.

The diversity of the structure (sheet, section steel – different thicknesses) causes a different surface appearance when cooling down and eventually thermal deformation. Therefore, it is advisable to galvanize sheet materials separately.

Laser fired products must have chamfered edges and grinded burnt surfaces. This allows for a better grip of the zinc on the edges of the product.

Cold formed profiles can result in a reinforcement of zinc coating in stripes in the direction of the drawing. The anticorrosion qualities of the coating are not restricted in any way.

The galvanizing of steel parts which have a size approaching or exceeding the size of the zinc bath needs to be consulted in advance with the production manager.

Tell us also about the subsequent surface treatment of the material (e.g. painting, powder coating, duplex coating) or the need to preserve functional surfaces of the construction.

Not suitable for galvanizing

Colour on the structure

Extremely greasy material

Slag, gaps, pores and inflammation in welds

Inadequate structural design, for example, combining materials with very different thicknesses.

Deep corrosion

When welding it is not appropriate to use substances containing silicone. We recommend release agents for silicone-free welding processes.

Paint handlers are not ideal for hot-dip galvanizing. We recommend alcohol or water-based handlers.

Material composition

We recommend galvanizing steel which contains silicon in the range of 0,12%–0,20% and below 0,03%.

We do not recommend galvanizing steel which contains silicon in the range of 0,03–0,12% of the mass (threat of the so-called Sandelin effect) and with a content of over 0,20%. Also, a higher content of phosphorus added to the content of silicon can lead to 
a reinforced reaction of the iron with zinc.