The construction sector uses a wide range of structural steels. These range from the rebar used for reinforcing concrete to the beams and sections used in steel buildings and the heavy structural steel plates used for key parts of the structure.
The construction sector covers a vast range of possibilities, but for Oakley Steel, the main focus is on providing structural steel that forms keys parts of the overall strength of the structure. In practice this means heavy structural steel plates of up to 200mm thick for base plates and important structural members.
A lot of our structural steel goes into bridges, viaducts and prestigious buildings however some is used in more exotic locations such as oil rings and offshore structures and as components in heavy machinery.
The main European structural steels are defined by the 6 EN10025 standards which covered hot rolled products for structural steels.
EN10025-2 covers the normal structural steels that are bought and used every day. These are typically grades like S235JR, S75JR and the higher yield S355J2+N and S355K2+N. Every country makes these grades with most of he production output focusing on the lower yield S235 and S275 grades. These are mild structural steels.
The higher yield structural steels are used for more important components that either need to be more reliable or take a higher load. As the quality of the structural steel increases it is generally able to perform to a better level at much lower temperatures.
EN10025-3 covers structural steels that have a fine grain structure. A fine grain in steel means that the steel is stronger and is often the result of normalising. These steels are typically used for lower temperature applications and are tested for that in the mill.
EN10025-4 covers thermomechanically rolled structural steels. For standard EN10025-2 steeks the alloy content is very low. By adding alloying elements the strength of the steel can be increased and thus the weight reduced. The yield strength also stays high even as the thickness increases. Thus thermomechanically rolled steels are able to save construction companies considerable amounts as they reduce the overall weight of the structure whilst providing the same strength.
EN10025-5 covers steels that are used in external environments and are subject to corrosions. Normal mild steels when exposed to the atmosphere and rain will tend to rust (or oxidise) and slowly corrode over time. For a large bridge this can mean constant maintenance and repainting to maintain and preserve the strength of the structural steel supports. Weathering steels, as described in EN10025-5, are unlike other structural steels, in that when exposed to the air the the surface forms a protective coating that prevents the steel below the surface from oxidising. Thus significant maintenance savings can be made and a structures life extended.
- We don’t supply weathering steels
EN10025-6 cover steels with a very high yield or strength. These steels are used in a couple of cases. In the first where a building design requires extremes loads to be placed at key points and normal structural steels have not got the strength. In the second when weight is a key consideration either due to the structure being movable (thus saving energy during its working life) or due to weight maxima implied by the design (for example on FPSOs and oil rigs where load balancing and displacement is key).
The downside is that as the yield goes up the plates become increasingly harder to weld – and weldability becomes a key characteristic in selection the plate supplier
Structural Steels supplied to SE Asia
We supply a full range of structural steels to construction companies across SE Asia. Most structural steel is purchased from local steel companies and their stockholders.
Our focus is on supporting customers when there are requirements for a prestigious or landmark building that requires very special plate. To many design engineers the qualities of our standard plates are comparable to customer designed ones from other mills.