Steel is the basic structural material in dozens of industries. Its greatest weakness, however, is corrosion – and this is exactly where steel electroplating turns out to be not so much useful as downright indispensable. What exactly does this method involve, where is it used, and how does zinc electroplating differ from hot-dip galvanizing?

Electroplated steel – what is it exactly and how does it differ from raw steel?

Electroplating is an electrochemical process of depositing metal on the surface of another material. In the case of steel, the protective metal most often used is zinc – applied by the electrolytic method, that is, by passing direct current through an electroplating bath in which the steel item acts as the cathode.

The result of the process is electroplated steel, that is, a material covered with a thin, uniform layer of zinc. The zinc coating protects the steel substrate in two ways: mechanically (a physical barrier cutting off access of oxygen and moisture) and electrochemically (zinc, as a more active metal, corrodes instead of the steel). Metal electroplating is therefore a controlled modification of the surface, not just a decorative outer layer.

The difference between electroplated and raw steel is fundamental – and visible to the naked eye. Electroplated steel has a characteristic, bright and uniform surface, while raw steel shows non-uniformity and quickly becomes covered with oxide deposits. Practical matters remain the most important here, however, because raw steel in contact with moisture and oxygen rusts after just a few days. In industrial practice, steel without any protection is used only for temporary applications.

Where is steel electroplating used? An overview of industries and applications

A systematic review of the electroplating process from 2024 indicates that electroplating remains one of the most widely used metal protection processes in modern industry, from decorative applications to heavy structures. It is hard to name an industrial sector that does not use electroplated steel; the scale of applications is simply enormous. Whenever steel works in conditions of elevated humidity, is exposed to contact with chemicals or variable temperatures, a zinc coating is the standard. Importantly, zinc electroplating works well both for larger structural components and for mass-produced small parts – this flexibility of the technology means that manufacturers from very different sectors turn to it.

Construction and steel structures

Electroplated steel components are widely used wherever steel details – anchors, fasteners, bolts, sections, facade elements, installation pipes – come into contact with the atmosphere or the ground. It is worth noting that electroplated zinc construction connectors retain dimensional precision, which is crucial when assembling prefabricated systems.

Automotive and transport

The automotive industry is among the largest buyers of zinc-electroplated components: from body parts, through electrical connectors, to springs and brake clamps. Electroplating in the automotive industry covers hundreds of different types of parts, often with complex geometry, where both corrosion protection and repeatability of coating thickness matter. It is electrolysis that makes it possible to meet both of these requirements at the same time. Electrolytically galvanized components have also found use in aviation, marine and rail transport.

Machinery industry

Machines working in changing environmental conditions, exposed to moisture, oils, chemical agents and so on, require components with durable surface protection. Bolts, nuts, shafts, brackets and thousands of other small parts made of electroplated steel are an everyday reality in the machinery industry. It is worth mentioning here that electrolytic zinc plating is one of the few methods that can protect very small components without the risk of sticking together or deformation – something the hot-dip method rules out. These capabilities are also the basis for using electroplating in electronics.

Electroplated vs galvanized steel – is it the same thing?

In everyday language, the terms "electroplating" and "galvanizing" are sometimes used interchangeably, but technically they describe different processes. It follows that electroplated steel versus hot-dip galvanized steel are two different products with different properties and applications.

Zinc electroplating (popularly referred to simply as electroplating) involves the electrolytic deposition of zinc from an aqueous bath at room temperature. It allows precise adjustment of coating thickness in the range of 3–25 µm and guarantees exceptional uniformity and surface aesthetics. It is the preferred method wherever dimensional accuracy and final appearance matter.

Hot-dip galvanizing (immersion), in turn, involves immersing the component in liquid zinc at approx. 450°C. The coating is thicker (typically from approx. 50 µm upward), and therefore considerably more durable, but less uniform. The high process temperature can also distort thin parts or precision components.

Does electroplated steel rust? Durability and limits of corrosion protection

The answer to the question about electroplated steel – does it rust, and what level of durability can be expected with this technology – is: yes, but only after the zinc layer has been used up. Zinc, as an electrochemically more active metal, corrodes instead of the steel, forming so-called white rust (zinc hydroxide), which subsequently turns into zinc zincate and zinc oxide, forming a fairly tight passive layer. As long as zinc is present, the steel remains intact.

The durability of the coating depends on its thickness, operating conditions and the environment. In standard rural and urban environments, a zinc coating 8–12 µm thick can protect steel components for several to a dozen or so years. In industrial or marine environments, wear is faster. Research published in the journal "Coatings" in 2018 confirms that electrolytically deposited zinc coatings show high corrosion protection effectiveness on steel substrates and are one of the most economically justified methods of protecting them.

Professional steel electroplating – how does the process work in a modern galvanizing plant?

Zinc electroplating in a modern electroplating shop comprises over a dozen stages: degreasing, pickling, surface activation, the actual electrolytic deposition in a controlled bath, passivation and final quality control. Every step must be monitored – bath temperature, current density, solution pH and process time translate directly into the quality of the coating.

At Strumet, an electroplating shop in Silesia serving both local and nationwide customers, the entire process takes place on fully automated production lines. Two process lines are available: the rack line – for components up to 2.8 m long – and the barrel line, intended for mass galvanizing of small parts. The plant is equipped with its own quality control laboratory, and wastewater management is based on a closed loop – with no industrial wastewater discharged into the environment. The order lead time is set individually, depending on the volume and the specifics of the parts (e.g., for a load weight of up to 100 kg, the service is completed within a day).

FAQ – the most common questions about electroplated steel

How does electroplated steel differ from hot-dip galvanized steel?

Electroplated steel is produced by the electrolytic method at room temperature, which yields a uniform and smooth coating 3–25 µm thick. Hot-dip galvanized steel has a thicker, rougher coating – very durable, but less precise. The electrolytic method is preferred where dimensional accuracy and aesthetics matter.

What is the maximum zinc coating thickness in electroplating?

In zinc electroplating, a thickness of 3–25 µm is typically achieved, depending on the customer's requirements and the intended use of the component. Thicker coatings are possible, but are used less often because of the economics of the process.

Is electroplated steel suitable for painting?

Yes, electroplated steel components are perfectly suitable for painting – both powder and liquid. The zinc coating provides an excellent adhesion substrate and at the same time a corrosion protection layer, which increases the durability of the entire paint system.

How long does zinc electroplating take and what does the lead time depend on?

The lead time depends on the batch size, the type of components (rack vs barrel) and the current load on the production line. For standard orders, lead times are usually as follows:

• up to 100 kg – up to 24 h,
• from 100 kg to 1 t – up to 48 h,
• from 1 to 3 t – up to 75 h.

For larger volumes, please contact our sales department directly. The daily throughput of the Strumet electroplating shop is 20,000 kg.