To provide a method for manufacturing a sour resistant steel sheet for a line pipe, which prevents degradation of strength and DWTT(drop weight tear test) characteristics, and can reduce the surface hardness.
The method for manufacturing the sour resistant steel sheet for the line pipe through accelerated cooling or direct quenching after hot rolling, comprises hot rolling steel which contains, by mass%, 0.02-0.08% C, and has CEQ value of 0.4% or less, which is expressed by CEQ=C+Mn/6+(Cu+ Ni)/15+(Cr+Mo+V)/5, acceleration cooling or directly quenching the steel sheet, and tempering it with rapid heating under condition of power density of 100 W/cm2 or higher, by using a solenoid type of an induction heating device having a frequency of 200-2,000 Hz. It is also characterized by the heated temperature on the steel surface in the range of 500-680°C during tempering, or the maximum hardness of the surface part of the steel sheet of less than Hv 220 and a yield strength of 413 MPa or more.
TSUJI AKIYOSHI
ISHIKAWA NOBUYUKI
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