STEEL PLATE WITH YIELD STRENGTH AT 890MPA LEVEL AND LOW WELDING CRACK SENSITIVITY AND MANUFACTURING METHOD THEREFOR

摘要

A steel plate with yield strength at an 890 MPa level and low welding crack sensitivity and a manufacturing method therefor. Weight percentages of components thereof are: C: 0.06-0.13 wt. %, Si: 0.05-0.70 wt. %, Mn: 1.20-2.30 wt. %, Mo: 0-0.25 wt. %, Nb: 0.03-0.11 wt. %, Ti: 0.002-0.050 wt. %, Al: 0.02-0.15 wt. %, and B: 0-0.0020 wt. %, where 2Si+3Mn+4Mo≤8.5, and others being Fe and inevitable impurities. The use of controlled thermo-mechanical rolling and cooling technologies is beneficial to improvement of steel plate strength, plasticity and toughness. The yield strength of the steel plate is greater than 890 MPa, the tensile strength is greater than 950 MPa, the charpy impact work Akv (−20) is greater than or equal to 120 J, and the welding crack sensitivity indicator Pcm is less than or equal to 0.25%.