Structural steel is a strong, reliable material used in a wide range of construction projects. Different types of steel offer different benefits, including resistance to corrosion, shape flexibility, and high strength. Here's a breakdown of the most commonly used structural steels and where they're best applied. This article looks at the main types of structural steel and their uses.
Common Types of Structural Steel
Mild Steel
Mild steel is one of the most commonly used steels in construction. It contains a low amount of carbon, making it easier to work with and weld.
Though not as strong as other types, it has good shape-holding properties and is suitable for general building purposes, including beams, plates, and columns.
High-Strength Steel
This steel contains a higher carbon content or other alloying elements that increase its strength. It is commonly used where a stronger material is needed without adding much weight.
Its ability to resist heavy loads makes it ideal for large-scale construction projects.
Weathering Steel
Also known as COR-TEN steel, weathering steel forms a protective outer layer of rust that helps prevent further corrosion. It is useful in outdoor environments where exposure to weather is a concern.
This type of steel reduces the need for paint and maintenance, making it a cost-effective choice in the long run.
Stainless Steel
Stainless steel includes chromium, which gives it excellent resistance to corrosion.
Though more expensive, it is preferred in areas requiring hygiene, aesthetic appeal, or where exposure to moisture is frequent. It’s also known for maintaining its strength and shape over time.
Tool Steel
Tool steel is typically used in the process of making tools and equipment due to its hardness and resistance to wear. It contains various alloys and is not usually used for large construction elements, but plays a vital role in the manufacturing of steel components.
Where Each Type Is Used
Buildings and Bridges
Mild steel and high-strength steel are the go-to choices for most building frames and bridge structures.
Their strength and ability to be shaped into beams, plates, and columns make them suitable for supporting loads and spanning large distances.
Industrial Units and Warehouses
In these settings, high-strength steel is often used to handle the weight of heavy machinery and stock.
Tool steel may also be present in equipment and machinery used during the construction process.
Roads and Railways
High-strength and weathering steel are ideal for these projects.
Weathering steel, in particular, helps reduce maintenance on exposed structures like railway bridges or roadside barriers, thanks to its natural corrosion resistance.
Coastal or Outdoor Structures
In areas exposed to salty air or wet climates, appropriately selected stainless steel or protected carbon steel may be suitable; weathering steel needs a separate assessment of salt exposure and wetting conditions.
These steels keep their shape and maintain strength, even in tough conditions.
Why the Right Structural Steel Type Matters
Choosing the right type of structural steel is essential for the safety, durability, and success of any construction project. Each material's strength, resistance to corrosion, and ability to hold its shape play a key role in how the structure performs over time. From the initial design stage through to final construction, knowing which steel to use helps ensure that columns, beams, and plates are fit for purpose and built to last in their specific environment.
Steel Grades and Section Shapes Are Different Choices
A universal beam, column, channel or hollow section describes a shape; a steel grade describes specified material properties. Beams commonly support floors and roofs, columns transfer loads towards foundations, and plates form connections and stiffeners. The same grade can be supplied in different shapes, so selecting a material is only one part of designing a load-bearing member. Connections, restraint and installation details also affect performance.
Understanding S275 and S355
Steel Construction Info identifies minimum yield strengths of 275 and 355 N/mm² for S275 and S355 respectively in hot-rolled material up to 16 mm thick. Specified strengths decrease with increasing thickness. These figures do not mean an S355 beam always carries a fixed percentage more load: deflection, buckling or connections may govern. Confirm the grade, toughness subgrade, product standard and dimensions with the structural engineer before fabrication.
Corrosion Protection and Maintenance
Weathering steel needs suitable wetting and drying conditions to develop its protective patina. Persistent dampness and salt exposure can make it unsuitable, so it is not an automatic choice for coastal structures. Painted or galvanised carbon steel and appropriately selected stainless grades offer other options. Consider drainage, exposure, surface preparation and maintenance access together. Stainless steel is corrosion resistant, but grade selection still matters in chloride-rich environments.
Current Steel Production Statistics and Procurement
The World Steel Association’s September 2026 release reports 144.2 million tonnes of crude steel production across 70 reporting countries in August 2026, down 1.2% from August 2025. This global indicator does not measure UK structural-steel availability or local prices. Obtain quotations against the actual grade, quantities, finish and delivery requirements, and retain the material and inspection records specified for the project.
Anderson Engineering And Welding Services are trusted structural steel suppliers serving Manchester and the North West. From design to installation, we deliver strong, custom steel solutions for commercial and residential projects.
