Patent ID: 9726305
Date: 2017-08-08
CPC Classifications: B23K,C21D,C22C,F16L,Y10T

Claim:
1. An electric resistance welded pipe comprising a base material having a chemical composition comprising, by mass %, C: 0.05 to 0.10%, Mn: 1.00 to 1.60%, Ti: 0.005 to 0.030%, Nb: 0.005% to less than 0.035%, and N: 0.001 to 0.008%, further comprising one or both of Si: 0.01 to 0.60% and Al: 0.001 to 0.10%, and a balance of iron and unavoidable impurities, wherein contents are restricted to P: 0.02% or less and S: 0.005% or less, and a Ceq, represented by the following formula 1, satisfies 0.23≦Ceq≦0.38, and having a metal microstructure comprising, by area ratio, 3 to 13% of martensite, and a balance of ferrite, an average value of an equivalent circle diameter of the martensite being 0.5 to 1.5 μm: where, in formula 1, C, M, Cr, Mo, V, Ni, and Cu are values which represent the contents of the elements by mass %.