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Hot-dip galvanising

The WIEGEL hot-dip galvanizing process according to DIN EN ISO 1461 guarantees top quality and long-term corrosion protection for up to 100 years.

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Corrosion protection is a matter of trust

Only by carrying out all process steps meticulously can a lasting result be guaranteed. That’s why the WIEGEL corrosion protection team not only offers outstanding process quality when it comes to protecting your steel. We also carry out all the associated services with the same degree of care: from order picking to fine cleaning to thread cleaning, from pre-assembly to special packaging (e.g. for overseas) to preservation, e.g. white rust protection.

From small parts to extensive steel structures, from one-off to serial products: our hot-dip galvanising process gives your steel lasting protection against rust. Depending on the thickness of the zinc coating and the ambient conditions, we can even achieve protection periods of over 100 years.

We are always on hand to offer you expert advice on all questions relating to the optimum preparation and design of parts and relating to the DASt directive 022. The experts at WIEGEL will support you with the best classification tools and carry out the necessary magnetic particle testing in each plant themselves.

Hot-dip galvanising is a process for protecting steel parts against corrosion. In this process, the steel parts are immersed in a bath of molten zinc, which forms a corrosion-resistant coating. The process produces a metallurgical reaction in which iron and zinc form an inseparable iron-zinc alloy in the coating. Thanks to the metallurgical reaction between zinc and steel (FeZn alloy), hot-dip galvanising is the only process that provides effective long-term protection against subsurface corrosion and is even capable of sealing minor damage thanks to its cathodic protection.

Hot-dip galvanising
Process

The process is divided into eight steps: set up, degreasing, pickling, fluxing, drying, hot-dip galvanizing, post-treatment and dismounting.

1. Set up

After delivery of the parts to be galvanised, an incoming goods inspection is carried out. The parts are then expertly set up in such a way that the subsequent processing steps can be carried out quickly, accurately and effectively.

2. Degreasing

The parts to be galvanized are transported on a rail car to the enclosed pretreatment area, where the material is first degreased using acidic cleaning agents in an aqueous solution. WIEGEL is the world’s first hot-dip galvanizer to fully enclose the pretreatment area and filter the exhaust air in an environmentally friendly manner.

3. Pickling

Pickling is carried out in diluted hydrochloric acid, which WIEGEL prepares in separate tanks based on the principle of segregated pickling. This means that pickling solutions with accumulating valuable substances such as iron and zinc are used separately, avoiding the mixing of these substances. This enables material processing in line with a sustainable circular economy. After pickling, another rinsing process is carried out.

4. Fluxing

The rinsing bath is followed by a flux bath. The flux provides a final, intensive fine cleaning of the steel surface and also increases the wettability between the steel surface and the liquid zinc. The flux typically consists of an aqueous salt solution of zinc chloride and ammonium chloride.

5. Drying

The fluxed material is then dried to ensure a high-quality and secure galvanizing process.

6. Hot-dip galvanising

The dried material is transported to the fully enclosed galvanizing furnace, where the pretreated steel is immersed in liquid zinc at 450 degrees Celsius. After immersion in the liquid zinc, the parts remain in the zinc bath until the physical reaction between the iron and the zinc is complete. Before removing the parts from the zinc bath, the surface of the zinc bath is cleaned of oxides and flux residues. WIEGEL has been operating lead-free for years, without adding lead to the zinc melts.

7. Post-treatment

The galvanized steel parts cool either in the air or in a water bath. Upon customer request, they can also undergo post-treatment. Post-treatment creates a clear, organic film for long-lasting shine and prevents premature white rust formation on galvanized surfaces.

8. Dismounting

The parts are then finished, meaning zinc spikes and residues on the zinc coating are removed. Before delivery, a final quality control of the galvanized material is carried out.

It is the knowledge and experience we bring to the overall process that ultimately determine the long-term quality as well as the impact on the environment.

 

WIEGEL hot-dip galvanising offers efficient logistics for the collection, preparation, post-processing, order picking and delivery of your steel. We know how important it is to meet deadlines and can deliver daily or directly to the construction site, as required. Our team of experienced professionals is committed to providing first-class service that enables timely and precise delivery of your steel.

 

WIEGEL’s own quality management and numerous certifications, including of course DIN EN ISO 1461, which is definitve for hot-dip galvanising, underscore the company’s commitment to quality. We also ensure that all employees are kept up to date with continuous further training and our own training system.

We provide you with comprehensive advice. Get in touch with your nearest WIEGEL contact person.

 

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