| 摘要 |
A steel plate for line pipes containing, in terms of % by weight, C: 0.02 to 0.06%, Si: 0.5% or less, Mn: 0.8 to 1.6%, P: 0.008% or less, S: 0.0008% or less, Al: 0.08% or less, Nb: 0.005 to 0.035%, Ti: 0.005 to 0.025%, and Ca: 0.0005 to 0.0035%, and optionally contains one or more of Cu: 0.5% or less, Ni: 1% or less, Cr: 0.5% or less, Mo: 0.5% or less and V: 0.1% or less, and has a CP value of 0.95 or less represented by CP=4.46C(%)+2.37Mn(%)/6+{1.18Cr(%)+1.95Mo(%)+1.74V(%)}/5+{1.74Cu(%)+1.7Ni(%)}/15+22.36P(%), and a Ceq value of 0.30 or more represented by Ceq=C(%)+Mn(%)/6+{Cr(%)+Mo(%)+V(%)}/5+{Cu(%)+Ni(%)}/15.
|
