Impact Testing Temperature
S355J0 and S355J2 are both structural steel grades under EN 10025-2 that differ mainly in their impact testing requirements. S355J0 is tested at 0 degrees C, meaning it is designed to maintain toughness at this temperature without becoming brittle. S355J2 is tested at minus 20 degrees C, making it suitable for colder environments where materials need to retain toughness at lower temperatures.
Charpy Impact Requirements
S355J0 requires a minimum impact energy of 27 J at 0 degrees C. S355J2 requires a minimum impact energy of 27 J at minus 20 degrees C. The lower test temperature of J2 demonstrates guaranteed toughness in colder service.
Mechanical Properties
Both grades have a minimum yield strength of 355 MPa and similar tensile strength, typically 470 to 630 MPa for thicknesses up to 100 mm. The differences in the J0 and J2 suffixes relate only to the impact test temperature, not the base strength.
Application Suitability
S355J0 is suitable for general structural applications where temperatures are around 0 degrees C or higher, such as indoor structures and mild climate regions. S355J2 is more suitable for colder climates or applications where temperatures may drop to minus 20 degrees C or lower, such as outdoor structures, bridges, and infrastructure in cold environments.
Grade Naming Explained
In the EN 10025-2 designation, S indicates structural steel, 355 is the minimum yield strength in MPa, and the suffix defines impact properties: JR requires 27 J at plus 20 degrees C, J0 at 0 degrees C, J2 at minus 20 degrees C, and K2 requires 40 J at minus 20 degrees C.
Frequently Asked Questions
Q: What is the difference between S355J0 and S355J2?
A: The impact test temperature: J0 at 0 degrees C and J2 at minus 20 degrees C, both with 27 J minimum.
Q: What is the yield strength of both grades?
A: 355 MPa minimum, with tensile strength around 470 to 630 MPa depending on thickness.
Q: Which grade suits cold climates?
A: S355J2, with guaranteed toughness at minus 20 degrees C for outdoor, bridge, and cold infrastructure.
Q: What does J0 mean in S355J0?
A: The steel must achieve 27 J Charpy impact energy when tested at 0 degrees C.
Q: Can S355J0 replace S355J2?
A: Only where the design temperature does not require minus 20 degrees C toughness; otherwise J2 must be specified.
Q: What is the difference between J2 and K2?
A: Both test at minus 20 degrees C, but K2 requires 40 J instead of 27 J minimum impact energy.
For S355J0 and S355J2 steel plate quotations with mill test certificates, contact our sales team.
