Steel Terms Glossary: Essential Metal Fabrication Terms

Steel fabrication refers to the process whereby steel sheet metal is turned into a product or structure. Skilled fabricators use a range of methods, equipment, and finishing processes to achieve the desired physical properties and design for each project, ensuring it perfectly fulfils its intended function. 

 

With a significant range of different steel grades and ways to shape and refine the metal, steel is a highly versatile material and is used for many different applications across a range of industries. 

 

Yet, with the number of steel construction terms involved, embarking on a new steel project can seem a little daunting. For this reason, we’ve pulled together a clear and concise steel glossary to help you understand the main terms. 

Why it’s important to know steel terms 

There’s a lot involved when taking basic raw materials and turning them into very specific parts, components or structures, especially when it comes to custom and bespoke designs. There’s no shortage of technicalities and jargon in the steel industry, and such a complex topic can understandably be a little off putting when you’re at the beginning of your project wondering where to start.

 

As a specialist metal fabricator with over three decades of experience behind us, we can help with your project and guide you through each step of the process, so there’s no need for you to be an expert on the topic and know all the terms inside-out. However, having a basic understanding of the main steel terminology can be beneficial to ensure you’re clear on specifications, designs and processes and know what’s happening with your project.

 

Key terms and what they mean in metal fabrication 

 

Types of steel 

 

  • Alloy steelA steel with more than one alloying element in addition to carbon and iron. Steel consisting of up to 8% alloying elements is considered low alloy, while anything over 8% is considered high alloy. Typically low alloy steel is more ductile and malleable, while high alloy steel has higher tensile strength and durability.

 

  • Austenitic – A popular and widely-used range of stainless steels, with mineral, austenite, as its primary phase. Austenitic steels are cold worked to harden and strengthen the metal. 

 

  • Carbon steel – Making up around 90% of all steel production globally, carbon steel is composed mainly of iron and carbon, and contains traces of alloying elements. The higher carbon content in the steel, the stronger and harder it is. 

 

  • Crude steel – Also referred to as raw steel, crude steel is the solid state after melting in the first stage of steel production. It can be sold in its current state or processed further.

 

  • Duplex steel – A type of stainless steel formed of a mixture of austenitic and ferritic structures. It’s highly corrosion resistant and often used for industrial applications.

 

  • Ferritic steel – Another type of stainless steel, ferritic steel is a chromium steel and is less corrosion-resistant than its austenitic counterparts. It’s often used for automotive parts and for interior architectural fixtures. 

 

  • High Strength Low Alloy (HSLA) One of our steel structure terms, HSLA steel is often referred to as primary steel. Produced using the Basic Oxygen Furnace (BOF) method, HSLA is strong and durable, and is often used for structural elements in buildings.

 

  • Mild steel – A type of low carbon steel that has high yield strength while being ductile and easily machined, making it suitable for a wide range of applications. 

 

  • Primary steel – Another one of our structural steel terms, primary steel is typically HSLA steel and used in construction, used for products like steel plates, building frames and columns to provide foundational support.

 

  • Secondary steel – Produced using an Electric Arc Furnace (ARF), secondary steel is made from mild steel and is often used to support primary steel structures and provide more functional elements to a build. It’s typically cheaper to produce than primary steel.


  • Steel grade – The categorisation of different steels by chemical composition, physical properties and mechanical properties. There are around 3,500 different types in existence, defined by various standards organisations. 


  • Stainless steel – The term for steel containing more than 10% chromium. It retains its strength at a high temperature and is durable, resistant to corrosion, and easily maintained, making it a popular choice for a range of settings. 

 

Stainless steel architecture

 

Common processes

 

  • Annealing – The process whereby steel is heated in a furnace and allowed to cool slowly  to soften so it can be more easily formed and bended.

 

  • Bending Changing the shape of the steel using specialist machinery, typically into a V shape, a U shape or a channel shape. Different types of bending include air bending and bottom bending, which you can read more on here.

 

  • Casting – Pouring molten steel into a mould it will take the shape of as it cools. 

 

  • CNC machining – Standing for Computer Numerical Control, CNC refers to the process whereby software is used to control the movement of tools and machines to create particularly complex and detailed custom components. 

 

  • CNC press breaking – Using Computer Numerical Control to precisely bend sheet metal into a specified shape. 

 

  • Cold rolling – Using mechanical force rather than temperature to change the shape of the metal, resulting in a very strong, smooth surface.

 

  • Continuous casting – Also known as strand casting, continuous casting refers to the process of pouring molten steel into water-cooled moulds to create a solidified ‘semi finished’ billet or slab of steel, before it goes to the mill for rolling. 

 

  • Coining – A form of stamping to shape the metal under high amounts of pressure, often used to create detailed parts like coins and badges.

 

  • Direct reduction – The process of obtaining iron from ore by removing the oxygen, using gases like carbon monoxide and hydrogen rather than melting down the metal. 

 

  • Flame cutting – Sometimes known as oxy-fuel cutting, flame cutting uses an oxyfuel gas flame to cut and shape the steel.

 

  • Hot rolling – Heating semi-finished steel and rolling it into long products, such as billets or slabs. Hot rolling typically increases the toughness, durability and weldability of the metal.

 

  • Milling – Using tools or machinery, like CNC mills, to remove excess material and accurately shape the metal into precise parts and components. 

 

  • Notching – A metal cutting process to remove material from the outer edges of the steel. It’s used for different reasons, including creating space for components like nuts, bolts and screws, and preparing the material for bending and forming. 

 

  • Quenching – Heating and then rapidly cooling steel using a ‘quenching’ medium, like oil, water or gas to make the metal harder and stronger. 

 

  • Tempering – A heat treatment that takes place after quenching whereby steel is heated to a temperature below its melting point and air-cooled to achieve the desired mechanical properties.

 

  • Welding – A process where separate metal pieces are joined together using heat, pressure, or both. This can be automated with robotics and is often used in the heavy steel industry.

 

Metal fabricator welding

Industry standards and qualifications to know

 

  • ASTM – An international standards organisation, previously known as the American Society for Testing and Materials and now referred to as ASTM International. ASTM develops and publishes technical documents and standards for products, materials and services that are adopted voluntarily by companies and institutions around the world. 


  • BS – British Standards are produced by the BSI Group, the national standards body for the UK. BSI produces technical standards for a range of services and products to promote quality and safety. 


  • CHAS – A provider of compliance and risk management solutions that sets compliance benchmarks and risk management standards across the UK. CHAS is a co-founder of Safety Schemes in Procurement (SSIP) and Common Assessment Standard (CAS).


  • EN – European technical standards documents, approved by the CEN, CENELEC or ETSI, that establish requirements for methods, procedures, items, materials and components. 


  • ISO – Standing for International Organisation for Standardisation, ISO is an independent international organisation, compromising standards bodies from 172 countries, that sets standards across safety, quality and efficiency.  


  • UKAS – The United Kingdom Accreditation Service assesses and accredits organisations that provide certification, inspection and testing services. UKAS is the only national accreditation provider recognised by the British government. 

 

Common tools and equipment used

 

  • Blast furnace – Used to smelt iron ore into pure iron, a blast furnace gets its name from the ‘blast’ that is created when coke, iron ore and limestone react under a hot air flow to form liquid metal. The furnace typically consists of a large cylinder, lined with heat-resistant refractory bricks. 

 

  • Basic Oxygen Furnace (BOF) – A BOF uses a blower or furnace to force oxygen into molten iron to reduce its carbon content. A high pressure stream of oxygen blown through the furnace causes chemical reactions that separate the impurities and create primary steel.

 

  • Caster – The machine used to mould liquid steel into continuous semi-finished steel products, like slabs and billets.

 

  • Electric Arc Furnace (ARF) – The method used to create secondary steel. An ARF uses an electric arc of graphite electrodes to generate heat and reduce the scrap iron, which is then blended with carbon and transformed into steel. 

 

  • Rolling Mill – A rolling mill reduces the thickness and transforms the shape of semi-finished steel products by squeezing it through carefully calibrated rollers to create long, flat products.

 

  • Ladle – A pre-heated cylindrical vessel in which molten steel is poured for temperature adjustment or treatment before the casting process. A ladle can also be used to transport the metal. 

 

  • Ladle furnace – Also known as a Ladle Metallurgy Furnace, a ladle furnace is the processing unit used to refine the molten steel into specialist grades while still in the ladle, before it goes into casting.  

 

  • Tundish – Used to regulate the flow of liquid steel as it passes from a  ladle to a mould for continuous casting. 

Steel finishes and coatings

 

  • Chrome plating – Where a thin layer of chromium is electroplated onto the steel, either for decorative purposes, to increase the hardness of the material, or for corrosion resistance. 

 

  • Cladding – The application of a stainless steel coating over a low alloy or carbon steel to  increase the strength and integrity of a structure, while adding another layer of protection against the elements. 

 

  • Electropolishing – A chemical process that removes a thin layer from the surface of the steel to leave a bright, smooth, shiny surface. 

 

  • Galvanise – A zinc coating applied to steel to provide a protective layer against corrosion and harsh environments.

 

  • Hardening – The process of heating steel and holding it to a certain temperature for a period of time before lowering the temperature slowly to increase the hardness of the material. 

 

  • Matte finish – A smooth, non-glossy appearance created with abrasive materials to dull the surface texture. 

 

  • Powder coating – Adding a dry powder to the surface under the steel and curing it under a high heat to add a thick, protective layer.

 

  • Wet spray – Applying liquid paint to a surface using an air gun to protect against corrosion, extreme temperatures and chemical elements. 

 

  • Zinc coating – Adding a zinc coating is also known as galvanising. Zinc coated sheets offer an additional layer of protection to stop the underlying steel corroding.
Applications of fabricated steel

 

  • Construction/architectural – Both structural steels and secondary steel are widely used in construction. Primary steel creates the main frame or ‘bare bones’ of a structure while secondary steel is used for the supporting and functional elements, for everything from brackets and joists to interior components like stairs and railings. 


  • Industrial – Steel fabrication is used for all sorts of products and components in industrial settings, for manufacturing plants, storage solutions, and parts for heavy equipment and machinery. 


  • Automotive and transportation – From road vehicles to aerospace, steel is widely used across the transportation industry due to its high strength to weight ratio and corrosion resistance. Galvinised steel is used for many vehicle body parts and engine components and it remains its integrity against the elements. 


  • Warehousing and materials handlingThe strength, durability and versatility of steel means its widely used in warehousing and materials handling. Steel products in this setting help with health and safety, movement, and storage, and include shelving, racks, pallets, trolleys, mezzanine flooring and staircases.

 

Need further support? 

Our steel terms glossary provides simple descriptions for just some of the terms and phrases you might come across when embarking on a steel fabrication project, but if you need any further guidance, or want to discuss your vision with an experienced steel fabrication professional, the friendly team at CSM are happy to help. 

 

Learn more about steel fabrication here, or get in touch with us to get the ball rolling on your next steel project. 

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