US4376662A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Methods for fabricating metallic workpieces
Assignee: Chem-Tronics Inc
•
Filing: 1980-05-05
•
Granted: 1983-03-15
•
Expires: 2000-05-05
Abstract
Abstract Methods for fabricating metallic components in which expansion of a mandrel and changes that take place in the workpiece material during precipitation hardening--phase changes, volume contraction, and increased ductility--are utilized to size the component to a selected diameter and to stabilize the component at that diameter. Mandrels for such methods.
Inventors
- 👤 Daniel J. Brimm
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 15:58
CPC Classifications
C; C21; C21D; C21D6/00; C21D6/02; C21D1/00
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
180 words
A method of fabricating a tubular component of selected dimension and physical properties which comprises the steps of: providing a workpiece which has a cylindrical configuration and is fabricated of a precipitation hardening alloy that undergoes a volume change and a change in crystalline structure during hardening and which retains a large part of its strength at the temperature required for precipitation hardening; inserting into the workpiece thus formed a mandrel fabricated of a heat resistant alloy having a higher strength and higher coefficient of expansion than the material of which the workpiece is formed; and then precisely sizing said workpiece by heating the resulting assembly at a sufficiently high temperature and for a sufficiently long time to first expand the workpiece to the wanted final dimension by expansion of the mandrel and plastic flow of the workpiece material and to then dimensionally stabilize said workpiece at said final dimension by effecting a phase change in the material of which said workpiece is fabricated that hardens said workpiece material and thereby prevents further changes in the dimensions of said material.
Claim 2
Independent Claim
180 words
A method of fabricating a tubular component of selected dimension and physical properties which comprises the steps of: providing a workpiece which has a cylindrical configuration and is fabricated of a precipitation hardening alloy that undergoes a volume change and a change in crystalline structure during hardening and which retains a large part of its strength at the temperature required for precipitation hardening; inserting into the workpiece thus formed a mandrel fabricated of a heat resistant alloy having a higher strength and higher coefficient of expansion than the material of which the workpiece is formed; and then precisely sizing said workpiece by heating the resulting assembly at a sufficiently high temperature and for a sufficiently long time to first expand the workpiece to the wanted final dimension by expansion of the mandrel and plastic flow of the workpiece material and to then dimensionally stabilize said workpiece at said final dimension by effecting a phase change in the material of which said workpiece is fabricated that hardens said workpiece material and thereby prevents further changes in the dimensions of said material.
Claim 3
Dependent Claim
35 words
A method as defined in claim 1 which includes the step of preheating the workpiece to accommodate the assembly of it and said mandrel by eliminating the need to form said workpiece to close tolerances.
Claim 4
Dependent Claim
30 words
A method as defined in claim 1 wherein said workpiece is sized and stabilized by two heating steps, the workpiece being cooled in air after each of said heating steps.
Claim 5
Dependent Claim
28 words
A method as defined in claim 1 wherein said workpiece comprises two or more joined together components, each of said components being fabricated of a material as aforesaid.
Claim 6
Dependent Claim
18 words
A method as defined in claim 1 in which the workpiece material is a precipitation hardening stainless steel.
Claim 7
Dependent Claim
38 words
A method as defined in either of claim 1 wherein said workpiece material is selected from the group consisting of 17-4 PH, 15-5 PH, 17-7 PH, PH 13-8 Mo, PH 14-8 Mo, and PH 15-7 Mo stainless steels.
Claim 8
Dependent Claim
18 words
A method as defined in claim 1 in which the workpiece material is a heat resistant Fe-Ni-Cr-Mo alloy.
Claim 9
Dependent Claim
53 words
A method as defined in claim 1 wherein the workpiece material is a precipitation hardening 17-4 PH or 15-5 PH stainless steel and wherein said workpiece is sized and stabilized by heating it at a temperature in the range of 900°-1150° F. for one to four hours and then cooling it in air.
Claim 10
Dependent Claim
62 words
A method as defined in claim 1 wherein the workpiece material is a precipitation hardening 17-4 PH or 15-5 PH stainless steel and wherein said workpiece is sized and stabilized by, sequentially, heating it at a temperature of 1400° F. for two hours, cooling it in air, reheating it at 1150° F. for one to four hours, and cooling it in air.
Claim 11
Dependent Claim
59 words
A method as defined in claim 1 wherein the workpiece material is a PH 13-8 Mo, PH 14-8 Mo, PH 15-7 Mo, or 17-7 PH precipitation hardening steel and wherein said workpiece is sized and stabilized by heating it at a temperature in the range of 875°-1150° F. for one to four hours and then cooling it in air.
Claim 12
Dependent Claim
67 words
A method as defined in claim 1 wherein the workpiece material is a PH 13-8 Mo, PH 14-8 Mo, PH 15-7 Mo, or 17-7 PH precipitation hardening stainless steel and wherein said workpiece is sized and stabilized by, sequentially, heating it at a temperature of 1400° F. for two hours, cooling it in air, reheating it at 1150° F. for four hours, and cooling it in air.
Claim 13
Independent Claim
120 words
A method of fabricating a tubular component of selected dimension, said method comprising the steps of: forming a material which undergoes a volume contraction upon heating into a workpiece of cylindrical configuration; inserting into the workpiece thus formed a mandrel fabricated of a heat resistant alloy having a higher strength and higher coefficient of expansion than the material of which the workpiece is formed; and then precisely sizing said workpiece by heating the resulting assembly to a temperature at which the workpiece will be expanded by expansion of said mandrel to the wanted final dimension and will undergo said volume contraction and a metallurgical phase change that will cause said workpiece to take a permanent set at said final dimension.
Claim 14
Independent Claim
120 words
A method of fabricating a tubular component of selected dimension, said method comprising the steps of: forming a material which undergoes a volume contraction upon heating into a workpiece of cylindrical configuration; inserting into the workpiece thus formed a mandrel fabricated of a heat resistant alloy having a higher strength and higher coefficient of expansion than the material of which the workpiece is formed; and then precisely sizing said workpiece by heating the resulting assembly to a temperature at which the workpiece will be expanded by expansion of said mandrel to the wanted final dimension and will undergo said volume contraction and a metallurgical phase change that will cause said workpiece to take a permanent set at said final dimension.
Claim 15
Dependent Claim
19 words
A method as defined in claim 12 wherein said workpiece is formed of a material which is precipitation hardenable.
Claim 16
Dependent Claim
26 words
A method as defined in claim 12 wherein said workpiece is formed of a material which can be hardened by aging it at an elevated temperature.
Claim 17
Dependent Claim
27 words
A method as defined in claim 1 or in claim 12 wherein the workpiece material is in an annealed condition prior to the time it is heated.
Claim 18
Dependent Claim
21 words
A method as defined in claim 1 or in claim 12 in which the mandrel is fabricated from A286 Fe-Ni-Cr-Mo alloy.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-03-14 | 1986-09-13 | 1987-03-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-03-14 | 1990-09-13 | 1991-03-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-03-14 | 1994-09-13 | 1995-03-15 | $7700.00 | Window Closed / Lapsed |