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The Steel Annealing Process: All You Need to Know

22 April 2022

At Buy A Beam, we recognise how hard our online steel suppliers work in producing and delivering UKCA-marked steel products to their local buyers. Not only is steel fabrication a multifaceted type of work, but so is treating all raw materials appropriately to ensure they maintain the desired quality and physical properties.

There are different methods for treating metals, all with specific applications. This guide specifically focuses on annealing, which aims to reduce the brittleness of steel and reduce the potential risk of the metal fracturing or failing.

Annealing texture on steel

What is Annealing?

Annealing is a heat treatment process used primarily to alter metals' physical and mechanical properties. Depending on the alloy, annealing can affect its chemical and electrical properties.

The heating process causes atoms to migrate, with the number of ‘dislocations’ dropping, thus leading to changes in ductility and hardness. As the metal cools, it recrystallises, with the crystal grain size and phase composition depending on the rates of heating and cooling.

Why is Metal Annealed?

Steel fabrication companies would generally anneal metals to reverse or reduce the effects of cold-working to give way for further steel fabrication processes, such as forming, shaping and stamping.

Annealing is primarily used to increase the ductility and reduce hardness of metals, which can be significant for a construction project requiring the assistance of a steel fabricator. The main reasons annealing is conducted are as follows:

  • Improved formability of materials - hard or brittle materials are difficult to press or bend without succumbing to fractures, which annealing helps reduce.

  • Enhanced machinability - brittle materials can wear down tools and machinery before long. Reducing their hardness can ensure a longer lifespan and reduce the wear on the steel fabrication equipment you use.

  • Removes residual stresses - these can create cracks and complications, which annealing can eliminate from occurring after the metal fabrication work has concluded.

What Metals Can be Annealed?

Full annealing is commonly used in mild and structural steel fabrication but can be used for most alloys that can be altered by heat treatment.

Examples include:

  • Cast iron
  • Wrought iron
  • Aluminium
  • Copper
  • Brass

Why Do Steel Suppliers Anneal Products?

Structural steel fabrication companies use annealing to help them create complex steel products, ranging from universal beams (I beams) to twinned steel columns and numerous other steel box sections. 

The idea behind annealing steel is to keep the material as workable as possible by returning it close to its original, pre-worked state.

Annealing Process Explained

There are three main stages to any annealing process used by structural steel fabricators.

  1. Recovery Stage

This is where a furnace or heating device is used to raise the steel’s critical temperature to a point where its internal stresses are relieved.

  1. Recrystallisation Stage

At this stage, the steel is heated above its recrystallisation temperature but below its melting point. This allows room for new grains to form without pre-existing stresses.

  1. Grain Growth Stage

The new grains fully develop during this stage. Their growth rate is dependent on how quickly the material cools.

Common Applications for Annealed Steels

  • Sheet metals that have been cold-rolled and require stamping, bending or punching
  • Drawing steel rods or metal wire from one size to a smaller one
  • Steel machining involving high temperatures or material displacement
  • Copper tubing that requires bending or has had its structure previously compromised

We hope that this guide has helped you understand the process of annealing more. It may sound convoluted, but it’s one of many steel fabrication processes that requires expertise, skill and intricate craftsmanship by trained metal specialists.

Buy Steel Online from Local Steel Suppliers

At Buy A Beam, we are proud to represent many nationwide steel stockholders who exhibit professionalism and quality assurance in ensuring their products are fit for purpose and will not fail. 

Whether they are fabricating a set of universal steel beams for a domestic construction project or a bespoke, cut-to-size steel frame building, we are firm in our belief that our online metal suppliers adhere to the highest standards and expectations. 

If you are responsible for project managing (wholly or partially) a domestic or commercial construction project, you can order steel online in just a few clicks from a local steel fabricator and supplier through Buy A Beam. You won’t have to worry about wait times for quotes and will instead receive an instant price for the steel you need, along with the length of time for delivery.

Our online shop will connect you to nearby structural steel companies with a full, up-to-date inventory of products in stock and add-on services such as crane hire. If this sounds like something you could be interested in, find out more here.