What is the Chinese equivalent of S355JR?
The closest Chinese equivalent to European S355JR structural steel is Q345B (under older GB standards) or the newer Q355B, both from the GB/T 1591 standard, offering similar yield strength and impact properties, though verifying specifications for specific applications is always recommended due to potential subtle differences in standards.
Understanding S355JR:
S: Structural steel.
355: Minimum yield strength of 355 MPa (for thicknesses up to 16mm).
JR: Indicates it passed a Charpy V-notch impact test at +20°C (room temperature).
Direct Equivalent: Q355B
Q355: Indicates the minimum yield strength of 355 MPa for thickness ≤ 16 mm (same as S355).
B: Indicates the impact toughness grade, specifying a test temperature of +20°C and a minimum impact energy of ≥34 J (Charpy V-notch). This directly corresponds to the "JR" requirement (27 J at +20°C). Note: The Chinese standard requires a slightly higher minimum impact energy (34J vs. 27J), making Q355B technically a bit more stringent in this aspect.
Historical Context & Comparison Table
The equivalence has evolved with changing standards:
S355JR
Q355B Q345B (Obsolete for this equivalence) Yield: 355 MPa, Impact: 20°C S355J0 Q355C Q345C Yield: 355 MPa, Impact: 0°C S355J2 Q355D Q345D Yield: 355 MPa, Impact: -20°C S355K2 Q355E Q345E Yield: 355 MPa, Impact: -40°C
Important Change: The Chinese standard GB/T 1591-2018 replaced GB/T 1591-2008. The major update was renaming Q345 to Q355 to align with international naming conventions (like Europe's S355 and the USA's ASTM A572 Gr. 50).
Therefore:
Q345B (old standard) is no longer the direct equivalent.
Q355B (new standard) is now the correct equivalent of S355JR.
Full specification and details are available on request. The above information is provided for guidance purposes only. For specific design requirements please contact our technical sales staff.
