Strenx 700 vs. Q690: Comparative Analysis

Strenx 700 and Q690 are two types of high-strength structural steels that follow different standard systems, with distinct performance characteristics and application scenarios. Below is a comparative analysis based on public data:
 

1. Standard System & Origin

Strenx 700: Manufactured by Swedish Steel (SSAB), compliant with European standards EN 10025-6 or EN 10149-2, classified as high-strength thermomechanically rolled (TMCP) or cold-formed structural steel.

Q690: A low-alloy high-strength structural steel under the Chinese national standard GB/T 1591-2018, widely used in construction, bridges, engineering machinery, and other fields.

2. Yield Strength

Strenx 700:

Minimum yield strength of 700 MPa (for some grades such as Strenx® 700 MC, the value can be reduced to 680 MPa when the thickness exceeds 8 mm).

Q690:

Minimum yield strength of 690 MPa, slightly lower than Strenx 700.

✅ Conclusion: Strenx 700 has marginally higher strength, with a clear advantage in thin-gauge specifications.

3. Low-Temperature Impact Toughness

Strenx 700:

Strenx® 700 MC D: Impact energy ≥ 40 J at -20°C;

Strenx® 700 MC E: Impact energy ≥ 27 J at -40°C;

Strenx® 700 E (heavy plate): Impact energy as high as 69 J at -40°C.

Q690:

Q690D: Impact energy ≥ 47 J at -20°C;

Q690E: Impact energy ≥ 47 J at -40°C (per some industry data).

✅ Conclusion: Both steels offer excellent low-temperature toughness, but Strenx 700 provides a broader range of low-temperature grades (e.g., -60°C), making it suitable for extreme cold environments.

4. Chemical Composition & Alloy Design

Strenx 700:

Tighter composition control, with carbon equivalent (CEV) typically ≤ 0.45% to optimize weldability;

Contains microalloying elements Nb, V, Ti to achieve grain refinement strengthening.

Q690:

C ≤ 0.18%, Mn ≤ 2.0%, with strict control of P/S content;

Also added with Nb, V, Ti, but the standard allows a slightly wider range of composition.

✅ Conclusion: Both adopt microalloying technology, while Strenx 700 features more precise control over composition and carbon equivalent, resulting in superior weldability.

5. Application Scenarios

Strenx 700:

Widely used in lightweight structures: such as truck chassis, crane booms, wind turbine towers, and engineering machinery;

Particularly suitable for precision processing such as cold forming, bending, and laser cutting.

Q690:

Mainly used in heavy-duty structures: such as core tubes of high-rise buildings, long-span bridges (Q690qC), mine hydraulic supports, and port machinery.

✅ Conclusion: Strenx 700 focuses more on lightweight design and manufacturing efficiency; Q690 prioritizes load-bearing capacity and engineering reliability.

6. Dimensions & Supply Forms

Strenx 700:

Thickness range: 0.7–160 mm, available in multiple forms including coils, narrow strips, and cut-to-length plates.

Q690:

Common thickness: 6–120 mm, width up to 4.5 m, length up to 18 m, mostly supplied as medium and heavy plates.

✅ Conclusion: Strenx 700 has an edge in thin plates and coils; Q690 is more mature in extra-large specification medium and heavy plates.

Supplementary Note

Q345D is a low-alloy steel plate under China's standard GB/T 1591, widely used in bridges, vehicles, ships, construction, and steel structures.

Q: Represents the yield strength of the material;

345: Indicates the yield strength is approximately 345 MPa;

D: Distinguishes it from grades A, B, C, meaning the steel plate is produced to meet impact test requirements at -20°C.

When heat treatment (such as normalizing) is required, the suffix N is added to the steel grade, commonly denoted as +N, e.g., Q345E+N.

Additional Table Translation