Nippon Steel Corporation

Tetsuya Magatani

Masahiro Ohgami

Naoki Takasugi

Osamu Takeda

The present invention provides an electric resistance welded steel pipe for a hollow stabilizer excellent in workability, which steel pipe contains, in mass, 0.20 to 0.35% of C, 0.10 to 0.50% of Si, 0.30 to 1.00% of Mn, 0.01 to 0.10% of Al, 0.10 to 1.00% of Cr, 0.005 to 1.00% of Mo, 0.001 to 0.02% of Ti, 0.0005 to 0.0050% of B and 0.0010 to 0.0100% of N, satisfying the expression N/14&#x3c;Ti/47.9, the balance consisting of Fe and unavoidable impurities and further has an ideal critical diameter (Di) being 1.0 (in) or more, an n-value in the axial direction of the steel pipe being 0.12 or more, a difference in hardness between the electric resistance welded seam portion and the base steel being Hv 30 or less, an average grain size of ferrite being 3 to 40 &#x3bc;m, an area percentage of the ferritic crystal grains having the aspect ratios of 0.5 to 3.0 being 90% or more in the entire ferrite phase, and having an average grain size of 20 &#x3bc;m or less in the second phase.

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Tokyo, Japan

Tetsuya Magatani