371 results about "Fatigue crack propagation" patented technology

The invention discloses a high-quality steel plate capable of resisting fatigue crack growth and a manufacturing method thereof. The high-quality steel plate comprises the following constituents in percentage by weight: 0.040-0.070% of C, 0.40-0.70% of Si, 1.30-1.60% of Mn, less than or equal to 0.013% of P, less than or equal to 0.003% of S, less than or equal to 0.30% of Cu, less than or equal to 0.30% of Ni, less than or equal to 0.10% of Mo, 0.008-0.018% of Ti, 0.015-0.030% of Nb, less than or equal to 0.0040% of N, 0.0010-0.0040% of Ca, and the balance of Fe and unavoidable impurities. The manufacturing method comprises the following steps: using the ultra-low carbon C-high Si-intermediate Mn-Nb system low alloy steel as a base, controlling [%C]*[%Si] to be 0.022-0.042 and {([%C]+3.33[%Nb])*[%Si]}*V cooling velocity / T cold shutdown to be from 1.15*10<-4> to 2.2*10<-3>, carrying out Ca treatment, enabling Ca / S to be equal to 1.0-3.0 and (%Ca)*(%S)<0.28> to be smaller than or equal to 1.0*10<-3>, optimizing the TMCP technology, enabling the finished product steel plate microscopic structure to become a ferrite and uniformly dispersed bainite dual-phase structure, and allowing the average grain size of the microscopic structure to be 10 microns below.