All You Need to Know about S355 Grade Steel
08 March 2022
If you’ve ever had to buy steel online for a construction project, you’ll probably be familiar with different types of steel grades.
Two of the most recognisable structural steel grades are S235 (which we’ve previously covered in detail in this blog post), and another is S355.
The steel suppliers using Buy A Beam’s online ordering system regularly supply structural steel products in the S355 grade. So what does this number signify, and what separates it from other steel grades? The steel fabrication experts at Buy A Beam have outlined that in this guide for you.
What is S355 Steel?
Structural steel is a building material made from steel grades, formed in a wide range of European Standard cross-sectional shapes. The grades given to structural steel products reflect their mechanical properties and chemical composition.
S355 steel falls in line with the European Standard EN 10025 classification and is widely-used structural steel used in numerous construction projects, similar to S235 and S275. In most countries, structural steel is regulated (indicated by UKCA or CE marking), meeting specific shape, size, chemical composition, and strength requirements.
The numerical indicator of “355” refers to the material’s yield stress (when at a nominal thickness of 16mm), with the “S” indicating that it is indeed made from structural steel.
How Strong is S355 Structural Steel?
S355 grade steel is a medium tensile, low carbon, manganese metal with a high strength-to-weight ratio, thanks to its raw materials. It’s a readily weldable, resilient and robust material containing good weather and impact resistance, even in extremely cold temperatures.
It goes without saying that before you order steel online from a metal fabrication company, you buy steel beams that are strong enough. This is where knowing the strength of S355 steel would come in handy.
To understand how strong this type of steel is, you need to measure the tensile strength and the yield strength. If you need clarification on these terms, the below explanation should hopefully help.
Yield Strength
Yield strength measures the minimum pressure needed to create a permanent deformation in the steel.
| Structural Steel at 16mm | ksi | N/mm² (MPa) |
|---|---|---|
| S355 | 50000 ksi | 355 N/mm² |
Tensile Strength
Tensile strength relates to the point at which a permanent deformation occurs when the material is stretched or pulled laterally. These impact tests are done prior to the products being sent for processing.
| Structural Steel Grade | Tensile Strength MPa at Nominal thickness between 3mm and 16mm |
|---|---|
| S355 | 470- 630 MPa |
The Chemical Composition of S355 Steel
The chemical composition of structural steel is vital; it defines the mechanical properties of the sheet metal. The percentages in the columns are the maximum levels of regulated elements present in S355 steel.
| EU Grade | Carbon % | Magnesium % | Potassium % | Sulphur % | Silicon % |
|---|---|---|---|---|---|
| S355 | 0.23 max | 1.60 max | 0.05 max | 0.05 max | 0.05 max |
Popular Uses for S235 Steel
While S355 steel isn’t the only supplied grade of steel on the market, it’s typically sold hot-formed or cold-rolled, with a defined cross sectional shape. This steel will have likely been engineered for specific applications.
You can usually find structural or mild steel products with the following product names:
- I Beams, H Beams or RSJs (commonly known as universal beams)
- CHS (Circular Hollow Section, like steel tube and pipe)
- RHS (Rectangular Hollow Section)
- SHS (Square Hollow Section)
- L-shaped steel plates (equal or unequal angles)
- Flat steel sections and bearing plates
- Universal columns
- Parallel Flange Channels (PFCs for short, also known as C channel or U channel steel beams)
The biggest consumer of structural steel is the construction industry, without a doubt. You’ll find structural steel lintels and beams used in numerous ways, from a series of load-bearing lintels in walls, or bolting steel girders in place to hold surfacing in place.
Other common uses for steel include:
- Domestic housing applications
- Agricultural buildings (see steel frame buildings)
- Offices and commercial buildings
- Factories
- Road barriers
- Bridges
- Railway tracks
- Sports stadiums
The fact remains that many local steel fabrication companies with Buy A Beam can manufacture and supply steel specifically designed for a particular application. You can find a range of steel beam sizes on the online store of a chosen supplier, but if you require something bespoke, you can enquire directly through Buy A Beam for any special product requirements.
Order Steel Online from Local Steel Suppliers
If you want to take advantage of a flexible, 24/7 steel purchasing solution that connects you with local steel fabricators and steel suppliers, with instant prices, no minimum order value and an easy purchasing system, look no further than Buy A Beam.
With a built-in steel beam calculator that enables you to customise order requirements as you wish, there is no easier one-stop shop for buying metals online.