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US 8,801,872 B2Granted
Secondary-hardening gear steel
AssigneeQuesTek Innovations LLC
InventorsJames A. Wright, Jason Sebastian
Life of this patent
Estimating the term…
Abstract
A case hardened gear steel having enhanced core fracture toughness includes by weight percent about 16.3Co, 7.5Ni, 3.5Cr, 1.75Mo, 0.2W, 0.11C, 0.03Ti, and 0.02V and the balance Fe, characterized as a predominantly lath martensitic microstructure essentially free of topologically close-packed (TCP) phases and carburized to include fine M2C carbides to provide a case hardness of at least about 62 HRC and a core toughness of at least about 50 ksi√in.
Claims8
A steel alloy comprising in weight percent:
- about 3.5 Cr, 16.3 Co, 1.75 Mo, 7.5 Ni, 0.02 V, 0.20 W, 0.11 C, 0.03 Ti, and the balance Fe
- with a carburized case having a hardness of 62-64 HRC and
- a core having a core fracture toughness greater than 50 ksi√in at room temperature,
- wherein said alloy has a lath martensitic microstructure matrix essentially free of topologically close-packed (TCP) phases with M2C carbide precipitates,
- wherein M is W and may optionally further be selected from the group comprising Mo, Cr, and V.
2 more elements
A case-hardened steel alloy comprising in weight percent:
- about 3.5 Cr, 16.3 Co, 1.75 Mo, 7.5 Ni, 0.02 V, 0.20 W, 0.11 C, 0.03 Ti, and the balance Fe
- with a carburized case having a hardness of 62-64 HRC and
- a core having a core fracture toughness greater than 50 ksi√in at room temperature
- wherein said alloy has a lath martensitic microstructure matrix essentially free of topologically close-packed (TCP) phases with M2C carbide precipitates,
- wherein M is W and may optionally further be selected from the group comprising Mo, Cr, and V.
2 more elements
Dependencies are inferred from the claim text.