Steel material having excellent hydrogen embrittlement resistance and impact toughness and method for manufacturing

A steel having, comprising:

• by weight %, carbon (C):
• 0.15-0.40%, silicon (Si):
• 0.4% or less (excluding 0%), manganese (Mn):
• 0.3-0.7%, sulfur (S):
• 0.01% or less excluding 0%, phosphorus (P):
• 0.03% or less excluding 0%, chromium (Cr):
• 0.6-2.0%, molybdenum (Mo):
• 0.15-0.8%, nickel (Ni):
• 1.6-4.0%, copper (Cu):
• 0.30% or less excluding 0%, niobium (Nb):
• 0.12% or less excluding 0%, nitrogen (N):
• 0.015% or less excluding 0%, aluminum (Al):
• 0.06% or less excluding 0%, boron (B):
• 0.007% or less excluding 0%, and a balance of Fe and unavoidable impurity elements,
• wherein a relationship of a total content SUM of specific impurity elements and contents of the C, Cu, Nb, Ni, Cr and Mo satisfies the following relational expression 1,
• wherein in a microstructure of the steel, 20/μm2 or more precipitates having a diameter of 20 nm or less are present,
• wherein the precipitates having the diameter of 20 nm or less are Nb(C, N),
• |(C-SUM)·(Cu-SUM)·(Nb-SUM)·(Ni-SUM)·(Cr-SUM)·(Mo-SUM)|×105>3.0, [Relational Expression 1]
• where SUM is the total content of specific impurity elements, and means the total content in wt % of [W+Nd+Zr+Co].