Hot-stretch-reduced electric resistance welded pipe

1 . A hot-stretch-reduced electric resistance welded pipe comprising:

a base metal portion and a weld portion,

a chemical composition of the base metal portion including, in mass %,

C: 0.210 to 0.400%,

Si: 0.05 to 0.50%,

Mn: 0.50 to 1.70%,

P: 0.100% or less,

S: 0.010% or less,

N: 0.0100% or less,

Al: 0.010 to 0.100%,

Ti: 0.010 to 0.060%,

B: 0.0005 to 0.0050%,

Cr: 0 to 0.500%,

Mo: 0 to 0.500%,

Cu: 0 to 1.000%,

Ni: 0 to 1.000%,

Nb: 0 to 0.050%,

W: 0 to 0.050%,

V: 0 to 0.500%,

Ca: 0 to 0.0050%, and

REM: 0 to 0.0050%,

wherein a remaining being Fe and impurities,

a Ti/N value obtained by dividing Ti content by N content is 3.0 or more,

in a microstructure of the weld portion,

an average grain diameter is 9.4 μm or less,

an area ratio of ferrite is 20% or more, and a remaining structure includes at least one selected from the group consisting of pearlite, bainite, and martensite, and

in a texture of the weld portion, an accumulation intensity of a {001} plane is 6.0 or less,

a critical cooling rate Vc90 of the base metal portion is 5° C./s to 90° C./s, and

the critical cooling rate Vc90 is expressed as the following equation (1), providing that a C content (mass %) is [C], a Si content (mass %) is [Si], a Mn content (mass %) is [Mn], a Cr content (mass %) is [Cr], a Mo content (mass %) is [Mo], and a Ni content (mass %) is [Ni],

log 10 Vc90=2.94−0.75×β  (1)

β=2.7×[C]+0.4×[Si]+[Mn]+0.8×[Cr]+2[Mo]+0.45×[Ni]  (2).

2 . The hot-stretch-reduced electric resistance welded pipe according to claim 1 , wherein the chemical composition includes, in mass %, at least one or two or more selected from the group consisting of:

Mo: 0.010 to 0.500%,

Cu: 0.010 to 1.000%,

Ni: 0.010 to 1.000%,

Nb: 0.005 to 0.050%,

W: 0.010 to 0.050%,

V: 0.010 to 0.500%,

Ca: 0.0001 to 0.0050%, and

REM: 0.0001 to 0.0050%.