Line Pipe Steel with Excellent Sulfide Stress Corrosion Cracking Resistance and Method for Manufacturing the Steel

摘要

PURPOSE: Provided is a method for manufacturing a line pipe steel with excellent sulfide stress corrosion cracking resistance by suppressing the formation of MnS inclusion. CONSTITUTION: The method includes the steps of reheating a steel slab comprising C 0.01 to 0.10 wt.%, 0.05 wt.% or less of Si, 0.20 wt.% or less of Mn, 0.015 wt.% or less of P, 0.01 wt.% or less of S, Al 0.01 to 0.1 wt.%, Ca 0.001 to 0.005 wt.%, a balance of Fe and incidental impurities to the temperature range of 1100 to 1300 deg.C, wherein the steel slab further comprises at least one element selected from 0.09 wt.% or less of Nb, 0.09 wt.% or less of V, 0.05 wt.% or less of Ti; hot rolling the reheated steel slab, wherein finish hot rolling temperature is 950 to 800C; and coiling the hot rolled steel sheet at 500 to 700C.