| 摘要 |
Disclosed is a welding structural steel product having fine complex precipitates of TiN and CuS is provided which contains, in terms of percent by weight, 0.03 to 0.17 % C, 0.01 to 0.05 % Si, 0.4 to 2.0 % Mn, 0.005 to 0.2 % Ti, 0.0005 to 0.1 % Al, 0.008 to 0.030 % N, 0.0003 to 0.01 % B, 0.001 to 0.2 % W, 0.1 to 1.5 % Cu, at most 0.03 % P, 0.003 to 0.05 % S, at most 0.005 % O, and balance Fe and incidental impurities while satisfying conditions of 1.2 </= Ti/N </= 2.5, 10 </= N/B </= 40, 2.5 </= A1/N </=7, 6.5 </= (Ti + 2A1 + 4B)/N </= 14, and 10 </= Cu/S </= 90, and having a microstructure essentially consisting of a complex structure of ferrite and pearlite having a grain size of 20 mu m or less. |
