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HIGH STRENGTH ELECTRIC RESISTANCE WELDED STEEL PIPE, METHOD FOR PRODUCING STEEL PLATE FOR HIGH STRENGTH ELECTRIC RESISTANCE WELDED STEEL PIPE USE, AND METHOD FOR PRODUCING HIGH STRENGTH ELECTRIC RESISTANCE WELDED STEEL PIPE

  • US 20180105893A1
  • Filed: 02/15/2016
  • Published: 04/19/2018
  • Est. Priority Date: 05/20/2015
  • Status: Active Grant
First Claim
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1. High strength electric resistance welded steel pipe characterized by having a chemical composition consisting of, by mass %,C:

  • 0.040 to 0.070%,Si;

    0.10 to 0.50%,Mn;

    1.60 to 2.00%,Nb;

    0.020 to 0.080%,V;

    0.060% or less,Ti;

    0.010 to 0.025%,Mo;

    0.20 to 0.40%,Ni;

    0.10 to 0.50%,Al;

    0.050% or less,3 Mo %+Ni %;

    more than 1.00%, anda balance of Fe and unavoidable impurities, whereinwhen using a point defined as a point ¼

    of the thickness in the thickness direction from the surface in the base material part of the steel pipe as a reference point, the metal structure in a region having a width of 0.5 mm in both the thickness directions from the reference point as a center consists of polygonal ferrite;

    10 area % or less and a balance of bainitic ferrite, anda thickness is 15.0 to 19.8 mm.

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