What is Q550D steel plate

Q550D steel plate introduction:
Q550D steel plates are usually delivered in the quenched and tempered state. When the customer needs the Q550D steel plate to have the performance in the thickness direction, a symbol representing the performance level in the thickness direction (Z direction) shall be added after the above specified grade, such as Q550D-Z15, Q550D-Z25, Q550D-Z35. Q550D means: "Q" is the first letter of the Chinese phonetic alphabet of "Qu" as the yield strength of steel; "550" is the yield strength value, in MPa; D - quality level is D (quality level is divided into C, D, E).

Executive standard of Q550D steel plate: GB/T 16270-2009; GB/T1591-2018
Element composition of Q550D steel plate:
Q550D C≤0.18, Mn 1.00-1.60, Si≤0.55, P≤0.030, S≤0.030, Al≥0.015

Mechanical properties of Q550D steel plate:
Yield strength ≥550 MPA
Tensile strength 670-830 MPA
Elongation≥16%
- 20℃ longitudinal impact energy ≥40J

Q550D steel plate is mainly used for important (low temperature) high-strength structural parts, engineering machinery, mining steel structural parts, etc.