29-09-2016 дата публикации
Номер: US20160281197A1
Автор:
Matteo Ortolani,
Ettore Anelli,
Michael L. Santella,
Govindarajan Muralidharan,
ORTOLANI MATTEO,
ANELLI ETTORE,
SANTELLA MICHAEL L,
MURALIDHARAN GOVINDARAJAN,
Ortolani Matteo,
Anelli Ettore,
Santella Michael L.,
Muralidharan Govindarajan
Принадлежит:
A tubular article can be formed from high temperature steam oxidation resistant and high temperature creep resistant alloy steel. The steel can include a chemical composition that include Fe, C, Si, Mn, Ni, Cr, Cu, Ti, Nb, Mo, and N, and optionally other elements. The steel alloy can include 0.06 to 0.15 wt % C, 0.1 to 0.5 wt % Si, 0.2 to 0.6 wt %, 0.05 to 0.4 wt % Ni, 4.5 to 6.0 wt % Cr, 1.0 to 2.0 wt % Cu, 0.04 to 0.08 wt % Ti, 0.01 to 0.06 wt % Nb, 0.45 to 1.2 wt % Mo, and 0.008 to 0.05 wt % N, up to 0.01 wt % of optional element Al, up to 0.01 wt % of optional element Zr, up to 3.0 wt % of optional element Co, up to 0.07 wt % of optional element V, up to 3.0 wt % of optional element W, up to 0.015 wt % of optional element P, up to 0.003 wt % of optional element S, up to 0.1 wt % of optional element Ca, up to 0.1 wt % of optional element Ta, up to 0.1 wt % of optional element Mg, up to 0.1 wt % of optional element Se, up to 0.1 wt % of optional element Te, up to 0.1 wt % of optional element B, up to 0.1 wt % of optional element Bi, and Fe. The steel can include copper precipitates and fine carbides, nitrides, or both. The steel can have a final microstructure comprising tempered martensite, tempered bainite, or a combination thereof. The steel can contain less than 2 vol % residual austenite. 2. The tubular article of claim 1 , wherein the steel contains less than 1 vol % residual austenite.3. The tubular article of claim 1 , wherein less than 4 wt % of the total Cr amount is stable in solid solution at room temperature.4. The tubular article of claim 1 , wherein the steel is comprising maximum 25 percent bainite.5. The tubular article of claim 1 , wherein wt % Ta+wt % Nb<0.1 wt %.6. The tubular article of claim 1 , wherein the copper precipitates have a grain size of less than 40 nm.7. The tubular article of claim 1 , wherein the fine carbides have a mean diameter of less than 200 nm.8. The tubular article of claim 7 , wherein the fine carbides have a size ...
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