The grade and finish of steel you require will depend on how you intend to use your components. Structural steel is widely used in construction, because it is easy to weld, both to itself and to other types of steel and compared to harder steels, it can be easily machined.
Structural steel has to meet industry standards for dimensional tolerances and composition. The properties of structural steel result from both its chemical composition and its method of manufacture.
Chemical composition of S275 and S355 Structural Steels
The main chemical components of structural steel include iron, carbon, and manganese, other additives include phosphorus, silicon, chromium vanadium and Tungsten. After iron, carbon is the most important element in structural steel which is why they are sometimes called carbon steels. The presence of carbon in steel makes it stronger and reduces the ductility, but lower carbon content makes it easier to weld. Finding the perfect balance is key when choosing the correct material for your purpose.
Manganese is one of the most common additives in structural steel after iron and carbon. It is essential for good machinability and it helps to avoid cracking and splitting during the rolling process. Small amounts of phosphorus improves machinability and increases the tensile strength, but too much makes it brittle. Sulphur is mostly regarded as an impurity, it can adversely affect the properties of structural steel.
Structural steel grades begin with an S. We supply and laser cut three grades of structural steel, S275JR, S355JR and S355J2.
Laser cut 15mm S275 components
Chemical content % by weight
Chemical content % by weight
|Carbon (C) max||0.25||0.23|
|Manganese (Mn) max||1.6||1.6|
|Phosphorus (P) max||0.04||0.05|
|Silicon (Si) max||0.05||0.05|
|Sulfur (S) max||0.05||0.05|
S275JR is available pickled & oiled (P&O) or dry, S355JR is available in untreated form or pickled & oiled and S355J2 is available dry. Take a look at the table below to see the thicknesses for each grade and finish that we supply and cut.
|Key||In stock||Available to order (lead times vary)||Not available|
|S275JR P&O||4mm, 5mm, 6mm,
|S275JR Dry||2.5mm, 3mm|
|S355 JR P&O||4mm|
|S355J2 Dry||3mm, 4mm, 5mm,
6mm, 8mm, 10mm,
Below we briefly explain the grades and finishes of structural steel that we supply.
WHAT DO JR & J2 MEAN?
JR and J2 refer to the mechanical characteristics of steel, specifically Charpy Impact tests.
The Charpy Impact test, also known as the Charpy V-notch test, is a standardised high strain-rate test that involves striking a horizontally placed notched specimen with a pendulum. The impact test helps measure the amount of energy absorbed by the specimen during fracture.
The J means that the test was conducted with 27 joules of energy. This is followed by either an R for room temperature, or a number referring to the temperature the tests were conducted at. So JR is room temperature (plus 20 degrees) J0 is 0 degrees and J2 is -20 degrees.
WE OFFER PICKLED AND OILED S275JR AND S355JR, WHAT DOES THIS MEAN?
Hot rolled steel products will oxidise through contact with oxygen and water vapor in the atmosphere after the forming process. To prevent this, the metal sheet or coil is passed through a pickling line. This is a bath of hydrochloric acid that removes any oxide scale that might have occurred during processing. Once the metal has passed through the acid bath it is rinsed, dried and then lightly oiled to protect the material from oxidisation. Pickling and oiling creates a clean surface finish, making it a much more user-friendly product for the laser cutting market.
WHAT IS DRY S275JR AND DRY S355JR?
Hot-rolled pickled dry steel sheet and coil is also descaled of oxides in a bath of hydrochloric acid and rinsed, but the material is not oiled afterwards.
If you need components cut from structural steel sheet or plate, you can find out more about the thicknesses, grades and finishes we supply on our mild steel page. If you know what you need email our sales team for a competitive quote firstname.lastname@example.org.