High strength steel having good toughness
First Claim
1. A steel tube, comprising:
- about 0.20 wt. % to about 0.30 wt. % carbon;
about 0.30 wt. % to about 0.70 wt. % manganese;
about 0.10 wt. % to about 0.30 wt. % silicon;
about 0.90 wt. % to about 1.50 wt. % chromium;
about 0.60 wt. % to about 1.00 wt. % molybdenum;
about 0.020 wt. % to about 0.040 wt % niobium; and
about 0.01 wt. % to about 0.04 wt. % aluminum;
wherein the steel tube is processed to have a yield strength greater than about 165 ksi and wherein the Charpy V-notch energy is greater or equal to about 80 J/cm2 in the longitudinal direction and greater than or equal to about 60 J/cm2 in the transverse direction at about room temperature.
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Abstract
Embodiments of the present disclosure comprise carbon steels and methods of manufacture. In one embodiment, quenching and tempering procedure is performed in which a selected steel composition is formed and heat treated to yield a slightly tempered microstructure having a fine carbide distribution. In another embodiment, a double austenizing procedure is disclosed in which a selected steel composition is formed and subjected to heat treatment to refine the steel microstructure. In one embodiment, the heat treatment may comprise austenizing and quenching the formed steel composition a selected number of times (e.g., 2) prior to tempering. In another embodiment, the heat treatment may comprise subjecting the formed steel composition to austenizing, quenching, and tempering a selected number of times (e.g., 2). Steel products formed from embodiments of the steel composition in this manner (e.g., seamless tubular bars and pipes) will possess high yield strength, e.g., at least about 165 ksi, while maintaining good toughness.
103 Citations
21 Claims
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1. A steel tube, comprising:
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about 0.20 wt. % to about 0.30 wt. % carbon; about 0.30 wt. % to about 0.70 wt. % manganese; about 0.10 wt. % to about 0.30 wt. % silicon; about 0.90 wt. % to about 1.50 wt. % chromium; about 0.60 wt. % to about 1.00 wt. % molybdenum; about 0.020 wt. % to about 0.040 wt % niobium; and about 0.01 wt. % to about 0.04 wt. % aluminum; wherein the steel tube is processed to have a yield strength greater than about 165 ksi and wherein the Charpy V-notch energy is greater or equal to about 80 J/cm2 in the longitudinal direction and greater than or equal to about 60 J/cm2 in the transverse direction at about room temperature. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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Specification
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- Resources
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Current AssigneeSiderca Saic
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Original AssigneeSiderca Saic
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InventorsAltschuler, Eduardo, Perez, Teresa, Lopez, Edgardo, Espinosa, Constantino, Gomez, Gonzalo
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Primary Examiner(s)WALCK, BRIAN D
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Application NumberUS14/068,868Publication NumberTime in Patent Office789 DaysField of Search148/333, 148/334, 148/519, 148/590, 148/593, 148/594, 148/653, 148/654, 148/663, 148/909US Class Current1/1CPC Class CodesC21D 1/25 Hardening, combined with an...C21D 2211/008 MartensiteC21D 8/105 of ferrous alloysC21D 9/08 for tubular bodies or pipesC22C 38/002 containing In, Mg, or other...C22C 38/02 containing siliconC22C 38/04 containing manganeseC22C 38/06 containing aluminiumC22C 38/22 with molybdenum or tungstenC22C 38/26 with niobium or tantalumC22C 38/44 with molybdenum or tungstenC22C 38/46 with vanadiumC22C 38/48 with niobium or tantalumC22C 38/50 with titanium or zirconiumY10T 428/12 All metal or with adjacent ...
