SERVICES
Hot-dip galvanising

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

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.

Degreasing

For degreasing, WIEGEL uses acidic or, less often, alkaline degreasing agents in an aqueous solution. Alkaline degreasing is followed by an additional rinsing bath to prevent carryover into the hydrochloric acid pickling.

Pickling

Pickling is carried out in diluted hydrochloric acid, which is prepared in different tanks at WIEGEL according to the principle of separate pickling. This means that pickling with zinc and pickling with iron are separated in order that as much waste as possible can be recycled. After pickling, a further rinsing process is carried out.

Fluxing/drying

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

Hot-dip galvanising

The fluxed material is now dipped into the molten zinc at 450°C. After dipping the fluxed material into the molten zinc, the parts remain in the zinc bath until they have reached the temperature of the bath. After “boiling out” the flux, the surface of the zinc bath is cleaned of oxides and flux residues and the product is drawn out. WIEGEL has been using a lead-free process, i.e. without adding lead to the molten metals, for years.

Cooling

The galvanised steel parts cool down either in the air or in a water bath. The parts are then buffed, i.e. zinc protrusions and residues on the zinc coating are removed. Before dispatch, the quality of the hot-dip galvanising is checked once again.

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.