In the context of steel materials, "domestic" typically refers to the Chinese national standard system (GB standards).
The European standard S355JR (EN 10025-2) is most directly equivalent to the Chinese standard Q355B under the GB/T 1591 standard (High strength low alloy structural steels).
Here's a detailed breakdown:
1. Primary Equivalent: Q355B (GB/T 1591)
This is the closest and most commonly used domestic substitute.
Similarities:
Minimum Yield Strength: Both are defined by a minimum yield strength of 355 MPa at thicknesses ≤ 16mm.
Application: Both are general-purpose structural steels used in construction, bridges, machinery, and general engineering.
Quality Grade: The suffix "JR" in S355JR indicates impact toughness of 27 J at +20°C. The suffix "B" in Q355B indicates impact toughness of ≥ 34 J at +20°C. Therefore, Q355B actually has a slightly higher toughness requirement at room temperature than S355JR. For most applications, this makes Q355B a suitable and often equivalent or superior replacement.
Key Standard: GB/T 1591-2018 (replaced the old Q345 standard).
2. Other Close GB Equivalents (Context-Dependent)
Depending on the specific requirements (like delivery condition or special properties), these may also be considered:
Q355C (GB/T 1591): Requires impact toughness of ≥ 34 J at 0°C. This is closer to the European S355J0 grade. Use this if your design calls for better low-temperature toughness than S355JR.
Q355D (GB/T 1591): Requires impact toughness of ≥ 34 J at -20°C. This is closer to the European S355J2 grade.
Q355E (GB/T 1591): Requires impact toughness of ≥ 27 J at -40°C.
3. For Steel Plates, Another Relevant Standard: GB/T 3274
The standard GB/T 3274 (Hot-rolled steel plates, sheets and strips for general structure) also includes a Q355B grade, which is generally consistent with the requirements in GB/T 1591. The material is often ordered or referenced under this standard for plates.
4. Important Note on the Older Standard: Q345
Before the GB/T 1591-2018 update, the dominant grade was Q345, which had a nominal yield strength of 345 MPa. The new Q355 series was introduced to align with international standards (like ISO 630 and EN 10025) and has fully replaced Q345 in technical specifications.
In the market, you might still hear people refer to "Q345," but for new designs and material procurement, Q355 is the correct, current designation. S355JR is equivalent to Q355B, not the old Q345.
Comparison Summary Table
| Property / Designation | S355JR (EN 10025-2) | Equivalent Domestic Material |
|---|---|---|
| Primary Equivalent | Structural Steel | Q355B (GB/T 1591-2018) |
| Minimum Yield Strength | 355 MPa (t≤16mm) | 355 MPa (t≤16mm) |
| Tensile Strength | 470-630 MPa | 470-630 MPa (Same range) |
| Impact Toughness | 27 J @ +20°C | ≥ 34 J @ +20°C |
| Main Application | General structural use | General structural use |
Selection Advice:
For direct substitution in most cases: Specify Q355B according to GB/T 1591-2018. The mechanical properties are essentially interchangeable, with Q355B having a marginally stricter toughness requirement.
If the design specifically calls for the exact toughness value of S355JR (+20°C impact): Q355B is still acceptable as it meets and exceeds that requirement. It is the standard choice.
For procurement: Clearly state the standard and grade: GB/T 1591-2018 Q355B. If it's for plates, you can also reference GB/T 3274.
Conclusion: The standard domestic material equivalent to European S355JR is Q355B according to the current Chinese national standard GB/T 1591.