Disclosed is a welding structural steel product having TiN and Zrn precipitates, which contains, in terms of percent by weight, 0.03 to 0.17 % C, 0.01 to 0.5 % Si, 0.4 to 2.0 % Mn, 0.005 to 0.2 % Ti, 0.0005 to 0.1 % A1, 0.001 to 0.03 % Zr, 0.008 to 0.030 % N,0.0003 to 0.01 % B, 0.001 to 0.2 % W, at most 0.03 % P, at most 0.03 % P, at most 0.03 % S, at most 0.01 O, and balance Fe and incidental impurities while satisfying conditions of 1.2 ≤ Ti/N ≤ 2.5 0.3 ≤ Zr/N ≤ 2.0 10 ≤ N /B ≤ 40 2.5 ≤ A1/N ≤ 7, and 6.8 ≤ (Ti+Zr+2A1+4B) / N$m (F)17, and having a microstructure essentially consisting of a complex structure of ferrite and pearlite having a grain size of 20 νm or less.
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