What is Q690D steel plate

Q690D steel plate meaning: Q is the first letter of the Chinese phonetic alphabet of the word "Qu" indicating the yield strength of the steel; 690 is the yield strength value, in MPa; D indicates that the quality grade is D, and the impact of grade D steel plate is -20; It belongs to high-strength welded structural steel, and Q690D can be called low-temperature high-strength steel with yield strength of 690mpa.

Delivery status of Q690D steel plate: quenching and tempering
Executive standard of Q690D steel plate: GB / t1591-2008, GB / t16270-2009
Q690D steel plate chemical element smelting analysis:
C≤0.18; Mn≤2.00; Si≤0.60; P≤0.025; S≤0.020; Nb≤0.11, V≤0.12; Ti≤0.20; Cr≤1.00; Ni≤0.80; Cu≤0.80; N≤0.015, Mo≤0.30; B≤0.004; Al≤0.015

Q690D steel plate mechanical properties
Yield: ≤16mm: ≥ 690; 16-40mm: ≥670； 40-63mm: ≥660； 63-80mm: ≥640。
Tensile strength: 730-940
Elongation: ≥ 14
Impact test: - 20 ℃: ≥ 47

The quality grades of Q690 steel plate are A, B, C, D and E respectively. If the performance in thickness direction can be required, the symbol representing the performance level in thickness direction (Z direction) shall be added after the above specified grade, such as Q690DZ15, Q690DZ25, Q690DZ35. Q690D steel plate has high yield strength and tensile strength, which is widely used in coal mining machinery and engineering machinery.