Back to results
US 8,261,767 B1Granted
Powdered metal inlay
AssigneeNovatech Holdings Corp.
InventorGeorge H. Blume
Life of this patent
Estimating the term…
Loading patent…
Loading patent…
AssigneeNovatech Holdings Corp.
InventorGeorge H. Blume
Estimating the term…
Differential coefficients of thermal expansion facilitate close approximation during cooling of a sintered cemented carbide tubular inlay preform (e.g., a first tubular portion) which is vacuum brazed within a corresponding tubular metal hull (e.g., a second tubular portion). Such a tubular inlay preform comprises at least one metal carbide and at least one nonvolatile cement which have previously been compressed and sintered in a predetermined shape. The tubular inlay preform's modulus of elasticity and thermal conductivity substantially exceed the corresponding parameters of the tubular metal hull, whereas the hull's coefficient of thermal expansion exceeds that of the preform. Longitudinal movement of a tubular inlay preform within a tubular hull may be limited by structural features of the hull and/or preform. Additionally, circumferential compression of a tubular inlay preform due to hoop stress in a corresponding tubular metal hull increases as the hull cools after vacuum brazing.
A sintered tubular inlay preform substantially symmetrical about an inlay preform longitudinal axis and comprising at least one metal carbide and at least one nonvolatile cement, said inlay preform having a preform first end spaced longitudinally apart from a preform second end, and said inlay preform further having a preform outer surface spaced radially apart from a preform inner surface, said preform first end extending a first radial distance between said preform outer surface and said preform inner surface, and said preform second end extending a second radial distance between said preform outer surface and said preform inner surface;
A tubular brazed assembly comprising a sintered first tubular portion sealingly vacuum brazed within a second tubular portion, said first tubular portion having a first coefficient of thermal expansion and a first modulus of elasticity, and said second tubular portion having a second coefficient of thermal expansion and a second modulus of elasticity, said tubular brazed assembly being substantially symmetrical about a longitudinal axis and having an inner surface and an outer surface, wherein said tubular brazed assembly has a thermal conductivity which decreases substantially monotonically from said inner surface radially to said outer surface, and wherein said second coefficient of thermal expansion exceeds said first coefficient of thermal expansion.
A tubular brazed assembly comprising a sintered first tubular portion sealingly vacuum brazed within a second tubular portion, said first tubular portion having a first coefficient of thermal expansion and a first thermal conductivity, and said second tubular portion having a second coefficient of thermal expansion and a second thermal conductivity, said tubular brazed assembly being substantially symmetrical about a longitudinal axis and having an inner surface and an outer surface, wherein said tubular brazed assembly has a modulus of elasticity which decreases substantially monotonically from said inner surface radially to said outer surface, and wherein said second coefficient of thermal expansion exceeds said first coefficient of thermal expansion.
Dependencies are inferred from the claim text.