High-strength steel sheet having excellent impact resistance, and method for manufacturing same

1. A steel sheet having impact resistance, comprising, in wt %:

0.05 to 0.12% of C, 0.01 to 0.5% of Si, 0.8 to 2.0% of Mn, 0.01 to 0.1% of Al, 0.005 to 1.2% of Cr, 0.005 to 0.5% of Mo, 0.001 to 0.01% of P, 0.001 to 0.01% of S, 0.001 to 0.01% of N, 0.001 to 0.03% of Nb, 0.005 to 0.03% of Ti, 0.001 to 0.2% of V, 0.0003 to 0.003% of B, and a remainder of Fe and unavoidable impurities,

a microstructure comprises tempered martensite as a main structure, and a remainder of tempered bainite,

the number of one or more of carbides and nitrides having a diameter of 0.1 μm or more per circle observed in a 1 cm 2 unit area is 1×10 3 or less,

the number of precipitates having a diameter of 50 nm or more including one or more of Ti, Nb, V, and Mo observed in a 1 cm 2 unit area is 1×10 7 or less,

the steel has a difference in hardness between a t/2 position and a t/4 position to 30 Hv or less, based on the thickness (t),

the steel sheet has a yield strength of 900 MPa or more, and a Charpy V-Notched energy at −40° C. of 30 J or more, and

the contents of Mn, Cr and Mo satisfy the following Relational expression 1:

T =Mn/(Cr+Mo), 1.0≤ T≤ 3.0  [Relational expression 1].

2. The steel sheet having impact resistance of claim 1 , wherein the contents of Nb, Ti, N, S, V, Mo, and C satisfy the following Relational expression 2,

Q =(Nb/93+Ti*/48+V/51+Mo/96)/(C/12), 0.2≤ Q≤ 0.5 Ti*=Ti−3.42*N−1.5*S, 0≤Ti*≤0.02.  [Relational expression 2]

3. The steel sheet having impact resistance of claim 1 , wherein tempered martensite of the steel sheet has 80% or more in an area fraction.