Surface & Heat Treatment Services

Metal surface treatment and coating allow you to give your product the desired look. But even more importantly, they lengthen the lifetime of metal. Smoothing the surface area and coating it afterwards protects metal from the surrounding environment.

Heat treatment enhances mechanical properties, relieves stresses, and refines the microstructure of metals, enabling them to meet specific performance requirements for a wide range of applications.

Why Order From Fractory?

  • Scale your production without switching suppliers, we can handle single orders upwards of 2 million pounds.
  • Discuss your surface and heat treatment needs with Fractory’s engineers for cost-efficient solutions.
  • Fractory handles everything from quoting to delivery, including quality control.
  • A single point of contact simplifies project management, freeing up time for value-added activities.
  • Quick quotes and lead times.
  • UK-wide delivery to your selected address.

Full service from cutting and bending to welding and surface coating

Get Quote
Manufacturing for 2500+ Businesses

Surface Coatings

Powder Coating

A widely used method for painting metal parts, powder coating gives a wide range range of colours. In the process, a dry powder is electrostatically applied to a metal part.

The next step is treating the parts with heat. The baking makes sure that the powder stays on the workpiece. The painted surface protects parts from corrosion and gives a nice look.

Wet Painting

The traditional way of painting by applying wet paint to parts. It is the right surface treatment method for metals that cannot be heated for powder coating purposes.

Traditional paints have a wider range of colours and allow the application of a thicker coating. Also, it is more long-lasting in some circumstances where powder coating cannot perform.

Galvanising

Galvanisation involves coating iron and steel with a layer of zinc for superior corrosion protection. The zinc acts as a protective layer that shields the underlying surface from corrosion and extends its lifespan. Galvanising is cost-effective and offers a long-lasting coating.

Two of the most common methods for galvanising are hot-dip galvanising and electrolytic galvanising. In the hot dip process, the part is dipped in a molten zinc bath and in electrogalvanising, the process is driven by electricity until a sufficient thickness of the zinc layer is developed.

Galvanising is commonly used in places where the metal needs to endure harsh environments or in structural applications where the metal needs to maintain its strength over many decades. The protective coating ensures that the base metal withstands challenging conditions without compromising its critical properties, such as tensile strength, elasticity and durability. The extensive utilisation of galvanised steel can be observed in the construction of bridges, guardrails and steel equipment in chemical plants.

Anodising

Untreated aluminium has low wear resistance and on exposure to the environment, it naturally forms a thin aluminium oxide layer that provides protection from corrosion. But this naturally formed oxide film can erode upon reaction with other environmental elements. The answer to providing better protection lies with anodising.

Anodising is an electrochemical process that develops an oxide coating on the surface of the part. This protects the product from wear and tear while improving the aesthetics. In this process, the product to be coated acts as an anode in an electrolytic cell, hence the name.

The process is mainly associated with aluminium, many other metals are suitable for anodising. Metals such as magnesium, titanium, zirconium, niobium, zinc, hafnium, and tantalum are anodised, albeit for different purposes.

Anodising is a premium finish, compared to plating and powder coating and can achieve a variety of different finishes which are authentic to the material they are mimicking.

Electroplating

During electroplating, a thin layer of metal atoms is deposited onto another material through electrolysis. By adding a layer of a different metal, several physical, mechanical and chemical properties of the workpiece can be improved.

In addition to improved corrosion and wear resistance, for example, electroplating is often carried out to improve the appearance of the product (e.g. nickel electroplating).

Black Oxide Coating

Black oxide coating is a conversion coating that enhances the corrosion resistance and appearance of metal parts by forming a protective layer on the surface. It is mainly performed on ferrous metals but the process is adapted for stainless steel, copper, aluminium and zinc as well. Blackening involves immersing the metal in a chemical bath that reacts with the surface to produce a thin, black finish. The extent of blackening depends on the dipping duration.

It is particularly effective for reducing light reflection and adding a sleek, matte look to parts. Commonly used in tools and automotive components, black oxide provides moderate protection while maintaining the dimensions of precision parts.

Surface Treatments

Deburring

Deburring is a finishing process that removes small burrs left on metal parts after machining or cutting operations. While laser cutting usually leaves nice clean edges on thinner sheets, other cutting methods may not have such great quality. These burrs can affect the functionality and safety of components, making deburring crucial for smooth edges and precision. It enhances the part’s appearance, reduces friction and wear, and minimises injury risk.

The process can be done mechanically, chemically, or thermally, depending on the complexity of the part. Mechanical deburring is the most common for general applications, where the parts are put on a deburring machine’s conveyor belt. The conveyor runs through a series of brushes that guarantee a quality surface. The belts are wide enough to accommodate large parts.

Sandblasting, Shot & Bead Blasting

Sandblasting and shot blasting are abrasive cleaning processes that use high-speed particles to clean, smooth or roughen metal surfaces. In sandblasting, shot media is propelled using compressed air, while in shot blasting, it’s driven by a centrifugal wheel.

Shot blasting is generally more aggressive, though this depends on media type and process settings. Both methods effectively prepare surfaces for coatings, enhancing adhesion and corrosion resistance.

Bead blasting is similar to shot blasting but uses glass beads or other softer media to achieve a smoother finish. This makes it suitable for applications that require gentler surface treatment, such as polishing or creating a satin finish on metals.

Electropolishing

Electropolishing, or anodic polishing, is an electrochemical process that uses electricity to remove a thin layer from electrically conductive metals, smoothening the surfaces. Unlike mechanical polishing, electropolishing works on a microscopic level, eliminating rough spots and surface defects to create a clean, reflective finish. However, it is frequently used as a secondary finishing process to supplement mechanical polishing.

In addition to reducing surface roughness, the process also improves corrosion resistance and cleans the parts, making it ideal for manufacturing components for high-precision industries like pharmaceuticals, food processing and electronics. Additionally, electropolishing helps prevent bacterial growth, making it a go-to choice for many hygienic applications.

Passivation

Passivation is a post-fabrication process that makes a material passive or inert to chemical reactions. It enhances the corrosion resistance of stainless steel by creating a passive oxide layer on the surface. This protective film prevents rust formation by shielding the metal from environmental factors like moisture and air.

The process involves immersing the metal in a mild acid bath to remove contaminants and promote the formation of the oxide layer. Passivation is frequently used in industries where long-term durability and cleanliness are critical, such as medical devices, food processing and aerospace.

Pickling

Pickling is a chemical treatment process that removes surface impurities such as rust, scale and oxides from metals like steel, stainless steel, aluminium and others. The metal workpiece is submerged in an acid solution called pickle liquor, which strips away these contaminants, leaving a clean, bright surface.

Pickling is often used before processes such as galvanising, plating or coating to ensure optimal adhesion and long-term performance. It is essential for ensuring the longevity and corrosion resistance of the metal in challenging environments.

Heat Treatments

Annealing

Annealing is used to reduce the hardness and increase the ductility and toughness of various steels, cast iron, aluminium and various alloys. It involves heating the workpiece beyond its recrystallisation temperature.

Annealing is usually done after a product undergoes mechanical operations (such as bending, forming, rolling, grinding, drawing, etc.) that lead to hard and brittle metals. This means that the material is difficult to process further and is susceptible to cracking. Thus annealing is most often carried out to return the metal to its pre-work state and make it more acceptable to subsequent operations.

The process is also used to relieve internal stresses as the final heat treatment operation to improve part service life and operational capabilities. In addition, annealing can also soften up weld solidifications and improve electrical conductivity.

Normalising

Normalising is actually a type of annealing process where the metals are cooled at room temperature instead of letting them cool at a controlled rate inside a furnace. Thus, the benefits and use cases for normalising are often similar to annealing – increased ductility and toughness accompanied by reduced hardness.

In applications where these properties are needed, normalising is a relatively quick and affordable way to achieve them as the process requires less furnace time. In most cases, normalising is enough if the components are not going to be under heavy loads.

For low-alloy and mild steels, the improvement in material properties is almost identical for annealing and normalising.

Tempering

Tempering is a heat treatment process in which the components are heated and held to a set temperature below the critical point for a certain duration. The components are then cooled to room temperature in still air.

Tempering is most often performed after hardening processes where the material is heated above its upper critical temperature followed by rapid cooling. To reduce the brittleness and restore ductility, the metals are reheated, this time to lower temperatures. This helps to strike a balance between hardness and ductility.

Tempered metals are useful in applications that need a certain level of flexibility from their components. In theory, tempering can be carried out on a wide range of metals but it is generally associated with carbon steel as few other metals react to this heat treatment method in the same manner as steel.

Quenching

Quenching is a rapid cooling process used to harden metals after they’ve been heated to a specific temperature above the recrystallisation point but below the melting point to allow grain restructuring. By immersing the heated metal in a cooling medium, such as water, oil, or air, quenching locks the material into a harder, more durable state.

This process increases the strength and wear resistance of components, making it ideal for applications that require high-performance characteristics. Quenching is commonly used for tools, machinery parts and structural elements. To obtain specific material properties, quenching is often followed by various other heat treatment methods, such as tempering or annealing.

Precipitation Hardening (Aging)

Precipitation hardening, or aging, is a heat treatment technique used to increase the yield strength of malleable materials, including some aluminium, nickel, and steel alloys. It typically follows quench hardening and itinvolves heating the metal to a high temperature, then cooling it slowly. While at first glance, tempering and aging might seem similar, they are thermodynamically really different, performed on different types of metals and yield different properties depending on the time and temperature they’re performed at.

Age hardening process causes small particles, or “precipitates,” to form within the material’s structure, preventing dislocational movements and boosting its hardness and durability. Ideal for components that need both strength and resistance to fatigue. For some alloys, aging can improve oxidation and corrosion resistance.

Case Hardening

Through case hardening, the surface of a metal is hardened while the core remains soft. This process allows to combine the best properties of a soft and hard metal into one part.

A soft material has superior impact resistance compared to a hard material. It possesses greater toughness, ductility, and strength but it does not have sufficient wear resistance. The presence of good wear resistance is important to prevent material degradation caused by abrasion or friction. By selectively hardening the outer surface, we can effectively minimise material wear while maintaining its other desirable properties.

If the carbon content is sufficient, we only need to heat and quench the part. But if the carbon content is low or extreme hardness is required, elements such as carbon (carburising) and nitrogen (nitriding) need to be added to the material’s surface.

Nitriding

Nitriding is a type of case hardening process that diffuses nitrogen into the surface of a metal, creating a hard, wear-resistant layer. The process occurs at relatively low temperatures, allowing for excellent dimensional stability and minimal distortion of the treated part.

Nitriding is commonly used on steel and stainless steel components that require enhanced surface hardness, fatigue strength, and corrosion resistance.

Let us ease your workload! Order metal fabrication from Fractory and experience the benefits yourself: 1-1 engineering support, payment terms for companies, a single point of contact, competitive pricing, on-time deliveries and quality control.
Get a Quote