US4364159A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for manufacturing a forged piston with reinforced ring groove
Assignee: Northrop Grumman Space and Mission Systems Corp
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Filing: 1980-07-14
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Granted: 1982-12-21
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Expires: 2000-07-14
Abstract
Abstract The method effects a tight fit of a ferrous ring reinforcement at the head end of an aluminum alloy piston which tight fit remains during use of the piston. The procedural steps of the preferred method include: providing an aluminum alloy piston slug with an annular shoulder adjacent its head end; solution heat treating the aluminum alloy slug for one hour minimum at a temperature within the range of from 483° C. to 510° C. (900° F. to 950° F.); rapidly cooling the solution heat-treated aluminum alloy slug to create a super-saturated aluminum alloy solid solution; preheating the ferrous ring to approximately 538° C. (1000° F.), a temperature above the head end temperature during use of the piston, to expand the ring temporarily; preheating the aluminum alloy slug to a working temperature of approximately 204° C. (400° F.), a temperature below the head end temperature during use of the piston; telescopically assembling the preheated and temporarily expanded ring on the head end against the shoulder and forging to cause the super-saturated aluminum alloy to flow axially and transversely against the temporarily expanded ring; and age hardening the super-saturated aluminum alloy at a temperature within the range of from 210° C. to 221° C. (410° F. to 430° F.) for about nine hours to cause a constituent precipitation which, together with contraction of said ferrous ring upon cooling, effects a tight fit which remains during use of the piston.
Inventors
- 👤 W. Philip Holcombe
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 20:51
CPC Classifications
F; F16; F16J; F16J9/00; F16J9/12; F16J9/22; B; B23; B23P; B23P15/00; B23P15/10; F02; F02F; F02F2200/00; F02F2200/04; F05; F05C; F05C2201/00; F05C2201/02; F05C2201/021; F05C2201/04; F05C2201/0433; F05C2201/0448; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49229; Y10T29/49249; Y10T29/49256; Y10T29/49826; Y10T29/49863; Y10T29/49865; Y10T29/49908; Y10T29/49915; Y10T29/49938
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
216 words
An improved method of producing an aluminum alloy piston having a ferrous ring reinforcement comprising the procedural combination of steps of: providing a generally cylindrical aluminum alloy piston slug having an annular shoulder between the head end and the skirt with the smaller diameter of the annular shoulder defining the outer diameter of the head end and the shoulder defining an annular surface transverse to the axis of the piston slug, solution heat treating the aluminum alloy piston slug, rapidly cooling the solution heat-treated piston slug to create a super-saturated aluminum alloy solid solution, preheating a ferrous ring to a temperature which is higher than the head end temperature during use of the piston in an engine to expand the ring temporarily and to provide an inner ring diameter larger than the outer diameter of the head end, preheating the cooled, solution heat-treated piston slug to a working temperature which is lower than the head end temperature during use of the piston in an engine, telescopically assembling the preheated and temporarily expanded ferrous ring on the head end of the preheated piston slug against the shoulder and forging to cause the super-saturated aluminum alloy solid solution to flow axially and transversely to the axis of the piston slug against the preheated and temporarily expanded ferrous ring.
Claim 2
Dependent Claim
216 words
An improved method of producing an aluminum alloy piston having a ferrous ring reinforcement comprising the procedural combination of steps of: providing a generally cylindrical aluminum alloy piston slug having an annular shoulder between the head end and the skirt with the smaller diameter of the annular shoulder defining the outer diameter of the head end and the shoulder defining an annular surface transverse to the axis of the piston slug, solution heat treating the aluminum alloy piston slug, rapidly cooling the solution heat-treated piston slug to create a super-saturated aluminum alloy solid solution, preheating a ferrous ring to a temperature which is higher than the head end temperature during use of the piston in an engine to expand the ring temporarily and to provide an inner ring diameter larger than the outer diameter of the head end, preheating the cooled, solution heat-treated piston slug to a working temperature which is lower than the head end temperature during use of the piston in an engine, telescopically assembling the preheated and temporarily expanded ferrous ring on the head end of the preheated piston slug against the shoulder and forging to cause the super-saturated aluminum alloy solid solution to flow axially and transversely to the axis of the piston slug against the preheated and temporarily expanded ferrous ring.
Claim 3
Dependent Claim
86 words
The method of claim 1 in which the super-saturated aluminum alloy solid solution is age-hardened after said step of forging to cause a constituent precipitation and to effect thereby a permanent expansion of the aluminum alloy which together with contraction of the ferrous ring resulting from cooling of the ring from the preheated and temporarily expanded condition for assembly effects a tight fit of the ferrous ring reinforcement at the head end of the aluminum alloy piston which tight fit remains during use of the piston.
Claim 4
Dependent Claim
30 words
The method of claim 3 in which said step of age-hardening is performed within the temperature range of from about 210° C. to about 221° C. for approximately nine hours.
Claim 5
Dependent Claim
30 words
The method of claim 1 in which said step of solution heat treating is performed at a temperature within the range of from about 483° C. to about 510° C.
Claim 6
Dependent Claim
31 words
The method of claim 4 in which said step of rapidly cooling includes quenching in water having a temperature within the range of from about 71° C. to about 82° C.
Claim 7
Dependent Claim
24 words
The method of claim 1 in which said step of preheating a ferrous ring is performed to heat the ring to approximately 538° C.
Claim 8
Dependent Claim
81 words
The method of claim 1 in which said step of providing the ferrous ring comprises the step of providing a ring of ferrous material having a composition consisting essentially of: a maximum of 3.00 percent by weight carbon, 1.00 to 2.80 percent by weight silicon, 1.00 to 1.50 percent by weight manganese, 13.50 to 17.50 percent by weight nickel, 5.50 to 7.50 percent by weight copper, 1.75 to 2.50 percent by weight chromium, and the balance being iron and trace impurities.
Claim 9
Dependent Claim
81 words
The method of claim 1 in which said step of providing the ferrous ring comprises the step of providing a ring of ferrous material having a composition consisting essentially of: 1.80 to 2.90 percent by weight carbon, 1.75 to 3.20 percent by weight silicon, 0.80 to 1.50 percent by weight manganese, 18.00 to 22.00 percent by weight nickel, 1.75 to 2.50 percent by weight chromium, a maximum of 0.2 percent by weight phosphorous, and the balance being iron and trace impurities.
Claim 10
Dependent Claim
29 words
The method of claim 1 in which said step of preheating the cooled, solution heat-treated piston slug comprises heating the piston slug to a temperature of approximately 204° C.
Claim 11
Dependent Claim
85 words
The method of claim 1 in which said step of providing the aluminum alloy piston slug comprises the step of providing a slug of aluminum alloy material having a composition consisting essentially of: 10.50 to 11.50 percent by weight silicon, 0.50 to 0.90 percent by weight magnesium, 1.50 to 2.00 percent by weight copper, 0.40 to 0.90 percent by weight manganese, a maximum of 0.70 percent by weight iron, a maximum of 0.40 percent by weight zinc, and the balance being aluminum and trace impurities.
Claim 12
Dependent Claim
46 words
The method of claim 1 in which said step of providing the aluminum alloy piston slug includes the step of providing a concave depression in its head end to facilitate flow of the super-saturated aluminum alloy axially and transversely to the axis during said forging step.
Claim 13
Dependent Claim
32 words
The method of claim 1 further including the step of cutting at least one annular piston ring groove in the cylindrical outer surface of the ferrous ring following the step of forging.
Claim 14
Independent Claim
288 words
A method of producing an aluminum alloy piston for use in an engine and having a ferrous ring reinforcement comprising the steps of: providing a generally cylindrical piston slug having a head end and a skirt and formed of an aluminum alloy capable of being age hardened at a temperature less than the operating temperature of the engine to cause a constituent precipitation with a resulting expansion of the alloy, the slug having an annular shoulder between the head end and the skirt with the smaller diameter of the annular shoulder defining the outer diameter of the head end and the shoulder defining an annular surface transverse to the axis of the piston slug, solution heat treating the aluminum alloy piston slug, rapidly cooling the solution heat-treated piston slug to create a super-saturated aluminum alloy solid solution, preheating a ferrous ring to a temperature which is higher than the head end temperature during use of the piston in an engine to expand the ring temporarily and to provide an inner ring diameter larger than the outer diameter of the head end, preheating the cooled, solution heat-treated piston slug to a working temperature which is lower than the age hardening temperature of the alloy, telescopically assembling the preheated and temporarily expanded ferrous ring on the head end of the preheated piston slug against the shoulder, thereafter forging to cause the super-saturated aluminum alloy solid solution to flow axially and transversely to the axis of the piston slug against the preheated and temporarily expanded ferrous ring, and, after said step of forging, age hardening the super saturated aluminum alloy solid solution at said age hardening temperature to cause a constituent precipation and therefore a permanent expansion of the aluminum alloy.
Claim 15
Independent Claim
288 words
A method of producing an aluminum alloy piston for use in an engine and having a ferrous ring reinforcement comprising the steps of: providing a generally cylindrical piston slug having a head end and a skirt and formed of an aluminum alloy capable of being age hardened at a temperature less than the operating temperature of the engine to cause a constituent precipitation with a resulting expansion of the alloy, the slug having an annular shoulder between the head end and the skirt with the smaller diameter of the annular shoulder defining the outer diameter of the head end and the shoulder defining an annular surface transverse to the axis of the piston slug, solution heat treating the aluminum alloy piston slug, rapidly cooling the solution heat-treated piston slug to create a super-saturated aluminum alloy solid solution, preheating a ferrous ring to a temperature which is higher than the head end temperature during use of the piston in an engine to expand the ring temporarily and to provide an inner ring diameter larger than the outer diameter of the head end, preheating the cooled, solution heat-treated piston slug to a working temperature which is lower than the age hardening temperature of the alloy, telescopically assembling the preheated and temporarily expanded ferrous ring on the head end of the preheated piston slug against the shoulder, thereafter forging to cause the super-saturated aluminum alloy solid solution to flow axially and transversely to the axis of the piston slug against the preheated and temporarily expanded ferrous ring, and, after said step of forging, age hardening the super saturated aluminum alloy solid solution at said age hardening temperature to cause a constituent precipation and therefore a permanent expansion of the aluminum alloy.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-12-20 | 1986-06-21 | 1986-12-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-12-20 | 1990-06-21 | 1990-12-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-12-20 | 1994-06-21 | 1994-12-21 | $7700.00 | Window Closed / Lapsed |