Q345R steel is primarily equivalent to ASTM SA516 Grade 70 (SA516 Gr.70) under the ASTM A516/A516M standard.
Here's a detailed comparison:
1. Core Equivalence: SA516 Gr.70
Standard Alignment:
Q345R is defined under the Chinese standard GB/T 713 for pressure vessel plates .
Its closest ASTM counterpart is SA516 Gr.70, designed for moderate-to-low temperature pressure vessels .
Key Properties:
| Property | Q345R (GB/T 713) | SA516 Gr.70 (ASTM) |
|---|---|---|
| Yield Strength | ≥345 MPa | ≥260 MPa (thickness-dependent) |
| Tensile Strength | 510–640 MPa | 485–620 MPa |
| Impact Test | -20°C (≥34 J) | -46°C to 0°C (varies by grade) |
| Q345R typically exhibits higher yield strength and stricter low-temperature impact requirements . |
2. Secondary Equivalents & Regional Alternatives
A572 Gr.50:
Used in structural applications (e.g., bridges, cranes) with similar yield strength (≥345 MPa) .
Differs in composition (lower carbon, added Nb/V) and lacks pressure vessel certification .
European Standard: EN 10028-2 P355GH is the common EU equivalent .
3. Composition and Performance Nuances
Chemical Differences:
Q345R: Higher Mn content (1.20–1.60%) with Nb/V micro-alloying for grain refinement .
SA516 Gr.70: Lower Mn (≤1.00%), no mandatory micro-alloying .
Functional Gaps:
SA516 Gr.70 offers better weldability with standard procedures, while Q345R requires stricter controls (e.g., preheating ≥125°C)
Q345R excels in low-temperature toughness (-40°C applications) and corrosion resistance in acidic environments .
4. Application Context
Shared Uses: Both are ideal for:
Pressure vessels (reactors, LNG tanks) .
Boiler components and structural parts in energy/chemical industries .
Q345R Specialization: Preferred in Chinese nuclear equipment (e.g., AP1000 reactor stabilizers) due to stringent impact standards
SA516 Gr.70 Dominance: Widely adopted in North American infrastructure for compliance with ASME codes .
Summary of Key Equivalents
| Standard | Equivalent to Q345R | Best For |
|---|---|---|
| ASTM | SA516 Gr.70 | Pressure vessels, boilers |
| ASTM | A572 Gr.50 | Structural frameworks |
| EN | P355GH | EU-regulated projects |
Just like you, 70% customers choose long-term cooperation with BBN steel not only for our good product and service quality, good reputation in the international market, but also for our experienced one-stop raw material supply and further steel processing!
