Low-silicon and low-carbon equivalent GPA grade multi-phase steel plate/steel strip and manufacturing method therefor

A low silicon low carbon equivalent multiphase steel plate/steel strip, comprising the following chemical elements by weight percentage:

• C:
• 0.03-0.07%, Si:
• 0.1-0.5%, Mn:
• 1.7-2.0%, P≤0.02%, S≤0.01%, N≤0.01%, Al:
• 0.01-0.05%, Cr:
• 0.4-0.7%, B:
• 0.001-0.005%, Ti:
• 0.07-0.15%, and further comprising Mo:
• 0.15-0.4%, and/or Nb:
• 0.02-0.08%, and a balance of Fe and other unavoidable impurities;
• at the same time, it satisfies:
• an effective content of B*≥0.001, the effective content of B*=B-[Ti-3.4N-1.2(C-Nb/7.8)]/22;
• CE<0.58, CE=C+Mn/6+(Cr+Mo+V)/5+(Si+Ni+Cu)/15;
• wherein the microstructure of the steel plate/steel strip contains ferrite and lower bainite, as well as 5% or less carbide precipitation phase, other inclusion phase and/or 0.5% or less martensite phase, wherein the content of ferrite is ≤20%, and the content of ferrite+lower bainite is ≥95%, in volume percentage;
• and
• wherein the steel plate/steel strip has a tensile strength of ≥980 MPa, a yield strength of ≥780 MPa;
• a hole expansion ratio performance satisfies that if the original hole is a punched hole, the hole expansion ratio is >50%;
• if the original hole is a reamed hole, the hole expansion ratio is >60%.