STEELS FOR SOUR SERVICE ENVIRONMENTS
First Claim
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1. A steel composition, comprising:
- carbon (C) between about 0.15 and 0.40 wt. %;
manganese (Mn) between about 0.1 and 1 wt. %;
chromium (Cr) between about 0.4 and 1.5 wt. %;
molybdenum (Mo) between about 0.1 and 1.5 wt. %;
wherein the average packet size, dpacket of the steel composition, the precipitate size of the steel composition, and the shape factor of the precipitates are selected to improve the sulfur stress corrosion resistance of the composition;
wherein the average packet size, dpacket of the steel composition is less than about 3 μ
m;
wherein the composition possesses precipitates having a particle diameter, dp, greater than about 70 nm and which possess an average shape factor of greater than or equal to about 0.62; and
wherein the shape factor is calculated according to 4 Aπ
/P2, where A is area of the particle projection and P is the perimeter of the particle projection.
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Abstract
Embodiments of the present application are directed towards steel compositions that provide improved properties under corrosive environments. Embodiments also relate to protection on the surface of the steel, reducing the permeation of hydrogen. Good process control, in terms of heat treatment working window and resistance to surface oxidation at rolling temperature, are further provided.
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8 Claims
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1. A steel composition, comprising:
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carbon (C) between about 0.15 and 0.40 wt. %; manganese (Mn) between about 0.1 and 1 wt. %; chromium (Cr) between about 0.4 and 1.5 wt. %; molybdenum (Mo) between about 0.1 and 1.5 wt. %; wherein the average packet size, dpacket of the steel composition, the precipitate size of the steel composition, and the shape factor of the precipitates are selected to improve the sulfur stress corrosion resistance of the composition; wherein the average packet size, dpacket of the steel composition is less than about 3 μ
m;wherein the composition possesses precipitates having a particle diameter, dp, greater than about 70 nm and which possess an average shape factor of greater than or equal to about 0.62; and wherein the shape factor is calculated according to 4 Aπ
/P2, where A is area of the particle projection and P is the perimeter of the particle projection. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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Specification