What do the letters and numbers in S235JR Quality signify?
Unlike many types of steel that are named after their chemical compositions, structural steels are named with expressions that indicate their mechanical properties. S235JR is a type of structural steel that you can obtain at reasonably affordable prices due to its widespread usage area and accessibility, especially if your design does not require high corrosion resistance, high mechanical strength, or wear resistance.
The initial "S" stands for "Structural," indicating that the material belongs to the group of structural steels. At room temperature (20°C), it signifies that the material can undergo plastic deformation up to a pressure of 235 MPa without losing strength in an impact test performed with 27 Joules of energy.
| Chemical Composition | ||||||||||
| Steel name | Steel no | Max. C rate (%) Thickness (mm) |
Max. Si rate (%) | Max. Mn rate (%) | Max. P rate (%) | Max. S rate (%) | Max. N rate (%) | Max. Cu rate (%) | ||
| ≤16 | >16 ≤40 | > 40 | ||||||||
| S235JR | 1.0038 | 0,17 | 0,17 | 0,20 | - | 1,40 | 0,035 | 0,035 | 0,012 | 0,55 |
| S275JR | 1.0044 | 0,21 | 0,21 | 0,22 | - | 1,50 | 0,035 | 0,035 | 0,012 | 0,55 |
| S355JR | 1.0045 | 0,24 | 0,24 | 0,24 | 0,55 | 1,60 | 0,035 | 0,035 | 0,012 | 0,55 |
| S355J0 | 1.0553 | 0,20 | 0,20 | 0,22 | 0,55 | 1,60 | 0,030 | 0,030 | 0,012 | 0,55 |
| S355J2 | 1.0577 | 0,20 | 0,20 | 0,22 | 0,55 | 1,60 | 0,025 | 0,025 | - | 0,55 |
S ⇒ Structural
235 ⇒ Minimum yield strength of 235 MPa
J ⇒ Minimum impact energy of 27 Joules
R ⇒At Room temperature (20°C)