Surface pre-treatment determines the success of a hot dip galvanizing operation. Effective degreasing, pickling and fluxing remove contaminants and create a reactive metallic surface ready for zinc bonding. ANI Metal offers targeted products—ANQA Degreaser for surface cleaning and Dragon Flux for oxide removal and fluxing—each formulated for industrial galvanizing conditions. This article explains how pre-treatment chemistry and technique influence coating uniformity, adhesion and appearance.
Table of Contents
1- Why Pre-treatment is Critical
Steel surfaces often carry oils, greases, paints, rust scales and mill residues. Without thorough cleaning, zinc cannot adhere uniformly, which can result in defects such as bare spots or excessive roughness. Pre-treatment is a multi-step process:
– Degreasing: Dissolves organic residues (oils, greases).
– Pickling: Removes oxides and mill scale using acid solutions.
– Fluxing: Replaces the protective oxide layer with a thin ionic film (typically zinc ammonium chloride) which promotes wetting in the molten zinc bath.
ANQA Degreaser and Dragon Flux are designed to integrate seamlessly into these stages.
2- ANQA Degreaser: effective degreasing for consistent results
ANQA Degreaser (https://www.animetal.com.tr/galvanizing-chemicals/anqa-degreaser) is formulated to remove machining oils, cutting fluids, and general plant contaminants prior to pickling. Best practices:
– Always use at recommended concentration advised by supplier.
– Make additions regularly (i.e 0.8-1.2 kg/per ton of steel) adjusting according to the oil level and surface area of the steels.
– If possible, keep the tank heated to improve efficiency.
3- Dragon Flux: flux formulation and dosing
Dragon Flux (https://www.animetal.com.tr/galvanizing-chemicals/dragon-flux) is engineered to remove residual oxides after pickling and prevent re-oxidation between drying and immersion. It contains 56% Zinc Chloride (ZnCl₂) and 44% Ammonium Chloride (NH₄Cl).
Key considerations:
– Maintain the recommended concentration and temperature to ensure maximum efficiency.
– Make additions regularly -ideally daily or at least weekly- with an average consumption of approximately 1.2 kg/per ton of galvanized steel.
– Where possible, use two rinse tanks, dipping the materials in both and allowing sufficient time for drainage to help keep the flux tank clean.
– Regularly monitor pH, density and iron concentration to maintain optimal bath conditions.
4- Common pre-treatment issues and fixes
– Poor coating & bare spots: Weak flux, contaminated flux or delayed immersion after drying. Solution: verify flux concentration and timing between drying and immersion.
5- On-Site Product Trials
Laboratory results do not always reflect real production conditions. For this reason, conducting controlled on-site trials is essential to confirm the correct dosing, contact time, and efficiency. These trials should be carried out in cooperation with the supplier, ensuring technical support is available and process parameters can be adjusted as needed.
Effective degreasing and fluxing are non-negotiable for consistent galvanizing. ANQA Degreaser and Dragon Flux exemplify the type of formulated products that, when applied correctly, reduce defects and improve overall efficiency of process. Integrating their use with proper sampling, training and process control leads to reliable, high-quality zinc coatings.
FAQ – Dragon Flux & ANQA Degreaser for Reliable Galvanizing
Q: What is the difference between degreasing and fluxing?
A: Degreasing removes organic contaminants; fluxing replaces oxide films to ensure the steel surface is chemically ready for molten zinc wetting.
Q: How long after fluxing should parts be immersed?
A: Minimize time between drying after fluxing and immersion—delays increase re-oxidation risk. Ideally, immersion follows immediately after drying.
Q: Can Dragon Flux be regenerated?
A: Flux regeneration can only be achieved using a flux treatment machine. This equipment reduces the level of soluble iron in the flux bath, adjusts the pH to the recommended range, and returns the treated solution to the galvanizing bath. For further information, https://www.animetal.com.tr/factory-equipment/flux-treatment-systems/