What is the difference between A517 Gr.Q steel plate and A517 GrQ modified steel plate

What is the difference between A517 Gr.Q steel plate and A517 GrQ modified steel plate

A517 Gr.Q steel plate is an alloy steel plate with high yield strength, which belongs to the steel plate for nuclear power, also known as the chain steel for offshore platforms. The same series of materials include A517 Gr.A, A517 Gr.B, A517 Gr.E, A517 Gr.F, A517 Gr.H, A517 Gr.S, A517 Gr.P, A517 Gr.Q, etc.

A517 GrQ modified steel plate is for marine engineering. A517 GrQ modified steel plate is an upgraded version of A517 Gr.Q steel plate.

Analysis of chemical composition and melting point of A517 Gr.Q steel plate:

C Si Mn P S Ni Cr Mo V
0.14-0.21 0.15-0.35 0.95-1.3 ≤0.025 ≤0.025 1.2-1.5 1-1.5 0.4-0.6 0.03-0.08

Analysis of chemical composition and melting point of A517 GrQ modified steel plate:

C Mn P S Si Ni Cr Mo V
0.14-0.21 0.95-1.30 ≤0.025 ≤0.025 0.15-0.35 1.20-1.50 1.00-1.50 0.40-0.60 0.03-0.08

Mechanical properties of A517 GrQ modified steel plate:
Tensile strength: 690-895
Yield strength: not less than 620
Elongation: not less than 16
V-type impact energy: not less than 46
Area shrinkage: not less than 50%