| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a double structure exhaust manifold hardly generating weld defect and good in high temperature strength of an inner pipe.SOLUTION: A base material part component contains, by mass%, 0.08% or less of C, 1 to 5% of Si, 3% or less of Mn, 0.08% or less of P, 0.02% or less of S, 10 to 30% of Cr, 7 to 18% of Ni and 0.25% or less of N and total 0.01 to 0.1% of Y and REM. A weld part component contains 0.08% or less of C, 0.5 to 3% of Si, 2% or less of Mn, 0.08% or less of P, 0.02% or less of S, 10 to 30% of Cr, 7 to 18% of Ni and 0.20% or less of N, and total 0.005 to 0.1% of Y and REM. An area of 200μm from a bond part to a side of the weld part in the inner pipe is 3.0% or more by a volume percentage of theδferrite amount and the volume percentage of a heterogenous phase is 2.0% .</p> |
