When selecting the right chain for your project, understanding the various types, grades, and protective coatings available is essential for ensuring durability, longevity, and suitability for your specific environment. Metal chains are manufactured with different finishes and from various steel grades, each offering distinct advantages for particular applications and environmental conditions.
The Fundamentals of Chain Manufacturing
Modern chain production begins with high-quality steel wire that undergoes a precise sequence of operations. The wire is drawn to exact diameters, cut to predetermined lengths, and formed into link shapes using automated bending machines. The critical stage involves welding the link ends together using high-frequency electrical resistance welding or flash butt welding – a process that occurs in milliseconds, creating a fusion zone that matches or exceeds the strength of the parent material.
After welding, chains undergo calibration to ensure consistency in the length of each link, whilst simultaneously testing the strength of the chain with particular focus on the welded sections. This meticulous process ensures that each link maintains structural integrity throughout its service life. Quality control technicians inspect sample links multiple times per shift, with data from each test stored electronically for future reference.
What is Galvanised Chain?
The Gold Standard for Outdoor Protection
Galvanised chain represents one of the most popular and economical choices for outdoor applications, offering excellent protection against corrosion and rust. The galvanisation process involves coating steel with a layer of zinc, which acts as a sacrificial barrier protecting the underlying steel from environmental exposure.
There are two distinct methods of galvanising, each producing significantly different results:
Hot-Dip Galvanising involves immersing the cleaned steel chain into a bath of molten zinc at temperatures between 830 and 870 degrees Fahrenheit. This process creates a thick, robust coating typically exceeding 0.1mm in thickness – often ten times thicker than alternative methods. The zinc coating provides multiple levels of protection: firstly, it creates a physical barrier isolating the steel from the environment; secondly, it offers cathodic protection where zinc molecules react with the environment to extend protection even when the surface is scratched or damaged.
Hot-dip galvanised chains are instantly recognisable by their characteristic muted grey colour and slightly rough texture. This finish can last for years or even decades without rusting, making it the preferred choice for permanent outdoor installations, marine applications, agricultural equipment, and construction sites. The substantial thickness means that as the zinc slowly corrodes, it produces zinc oxide, which actually adds another protective layer.
Zinc Plating (Electro-Galvanising) uses a fundamentally different approach. The steel chain is submerged in an electrolytic solution containing zinc salts, and an electric current is passed through the solution. This causes zinc ions to bond to the steel surface, creating a much thinner coating – typically between 0.005mm and 0.025mm.
Zinc-plated chains are noticeably smoother and shinier than their hot-dip counterparts, often with a bright, uniform appearance that many find more aesthetically appealing. However, this thinner coating means zinc-plated chains offer substantially less corrosion resistance and are generally unsuitable for prolonged outdoor exposure unless treated with additional protective coatings. They excel in applications where cosmetic appeal matters or where the chain will be used in controlled, indoor environments.
Black Japanned Chain: Traditional Protection with Contemporary Appeal
Black japanned chain represents a traditional finishing method that remains popular for both functional and decorative applications. The term "japanned" historically referred to a lacquered black finish, though modern black japanned chains typically feature an electro-plated black coating or black lacquer applied to mild steel.
This corrosion-resistant finish provides a protective barrier against weathering whilst offering a distinctive, sleek aesthetic that works particularly well for decorative purposes in gardens, interior design, suspended lighting fixtures, and architectural features. The black coating is durable enough for both indoor and outdoor use, though it may wear in areas subject to heavy abrasion or dragging across rough surfaces.
Black japanned chains combine the practical benefits of corrosion protection with visual appeal, making them ideal where functionality meets design. The coating prevents rust whilst maintaining a consistent appearance that complements both traditional and contemporary settings.
Stainless Steel: Premium Corrosion Resistance
For applications demanding the ultimate in corrosion resistance, stainless steel chains represent the premium choice. Unlike coated chains where protection depends on an external layer, stainless steel's corrosion resistance is intrinsic to the material itself.
Grade 316 Stainless Steel stands as the marine industry standard, known scientifically as 1.4401 (DIN/EN) or AISI 316 (American designation). This austenitic stainless steel contains approximately 16-18% chromium, 10-14% nickel, and 2-3% molybdenum. The molybdenum content is particularly crucial, as it significantly enhances resistance to pitting corrosion in chloride environments – the primary threat in coastal and marine applications.
The chromium in stainless steel forms a passive protective layer of chromium oxide on the surface. This invisible film is self-healing; when scratched, the chromium reacts with oxygen to immediately repair the protective layer. This makes grade 316 stainless steel chains particularly suitable for marine moorings, coastal installations, food processing environments, and any application where exposure to salt, chemicals, or moisture is inevitable.
Stainless steel chains are non-magnetic, have a distinctively bright, polished appearance, and remain smooth throughout their service life. Unlike galvanised chains, they don't develop the rough, flaky patina associated with zinc corrosion. This makes them particularly suitable where cleanliness and aesthetic appearance are priorities alongside corrosion resistance.
The smoother surface of stainless steel chain also offers practical advantages – it stows more neatly without 'coning' in storage areas, and dirt, silt, and mud wash off far more easily than from galvanised surfaces. However, despite the name, stainless steel can still experience surface staining in certain conditions. These marks can typically be removed using specialist stainless steel cleaning agents.
Unfinished and Brass-Plated Chains: Specialised Applications
Unfinished steel chains receive no protective coating after welding, displaying the raw steel finish. These chains are typically the most economical option and are suitable for applications where corrosion isn't a concern – such as short-term indoor use, theatrical productions, or situations where the chain will be painted or coated by the end user. Without protection, unfinished chains will develop surface rust when exposed to moisture.
Brass-plated chains combine a steel core with an electroplated brass finish, offering a warm, golden appearance that's particularly popular for decorative applications, lighting fixtures, and period property restoration. Whilst brass plating provides some corrosion resistance, it's primarily chosen for its aesthetic qualities rather than as a heavy-duty protective coating.
Choosing the Right Chain for Your Environment
When selecting chains for corrosion resistance across all weathers and environments, the hierarchy is clear:
For supreme corrosion resistance in the harshest conditions – including marine, coastal, industrial chemical exposure, and food processing – grade 316 or 316L stainless steel chains are unmatched. Their intrinsic corrosion resistance, self-healing properties, and smooth finish make them the ultimate choice where longevity justifies the higher initial investment.
For excellent all-weather protection at moderate cost, hot-dip galvanised chains provide decades of reliable service. The thick zinc coating withstands outdoor exposure, agricultural use, and general construction applications admirably. This represents the best balance of performance and value for most outdoor applications.
For indoor or decorative outdoor use where moderate protection suffices, zinc-plated or black japanned chains offer adequate corrosion resistance combined with superior aesthetics. These finishes excel where appearance matters and exposure to extreme conditions is limited.
Understanding these differences ensures you select the right chain for your specific requirements, balancing performance, longevity, aesthetics, and budget to achieve optimal results for your project.
If you have any queries about the chain you require get in touch with our team and we'll do our best to answer your question and point you in the direction of the product that best suits your needs.