Detailed explanation of Q550D steel plate

The Q550D steel plate is not as famous as the Q690D steel plate, and its range of use is relatively narrow. However, in some relative situations, only the Q550D steel plate can be used, and higher strength steel plates cannot be used instead. Therefore, there is no saying which steel plate is better than which, just because it is used in different directions. In recent years, pollution has become increasingly severe, so the focus of development has shifted to greenery. It is precisely against these backgrounds that Q550D high-strength steel plate has emerged.

Chemical composition of Q550D steel plate (melting analysis):
C 0.13-0.18%
Si 0.20-0.50%
Mn 0.90- 1.30%
P 0.90- 1.30%
S 0.90-1.30%
Ni 0.90- 1.30%
Cr 0.30-0.60%
Mo 0.40- 0.60%
Nb 0.020- 0.050%
Al 0.020-0.050%

Mechanical properties of Q550D steel plate:
Yield strength 545MPa, tensile strength 682MPa, elongation 20%, longitudinal impact energy 146J, 128J, 135J, -20 transverse impact energy 152J, 141J, 122J, Z-direction performance 50%, 53%, 49%; Steel plate macrostructure porosity and segregation level ≤Level 1.0, meeting the requirements for low alloy ultra-thick steel plates used in large water turbine units.

Please note that the chemical composition and mechanical properties of Q550D steel plate are not absolute, so the specific details should still refer to the MTC.

Executive standards for Q550D steel plate:
The Q550D steel plate follows the standard GB/T1591-2018.

Delivery status of Q550D steel plate:
The Q550D steel plate adopts a quenching and tempering heat treatment process, which involves two rounds of heat treatment, first quenching and then tempering. This can improve the strength of the steel plate and also enhance the internal toughness of the Q550D steel plate.