Claims
- 1. Method of producing a component having a rigid joint between two dissimilar metals in a forging operation, comprising the steps of:
- (a) providing a first metal part in a predetermined shape;
- (b) determining an interface between the first part and a second metal part;
- (c) machining the first part into a final form at the interface;
- (d) plating the first part at the interface with a plating material having a property of inhibiting dissimilar metal corrosion;
- (e) coating a billet, of the metal from which the second metal part is to be formed, with boron nitride where the billet is to contact the interface in the forging operation;
- (f) heating the boron nitride coated billet in a nonoxidizing atmosphere at a temperature sufficient for the boron nitride to change from a white state to a black state, thereby heating the boron nitride and changing the boron nitride from a white state to a black state, prior to the forging operation;
- (g) establishing the first part at a temperature below that required for plastic deformation during the forging operation;
- (h) heating the billet to a forging temperature;
- (i) placing the first part into a pre-determined position in a forging die;
- (j) placing the billet into a second pre-determined position in the forging die;
- (k) applying forging pressure against the billet, thereby forming the billet into the second part, and thereby joining the second part to the first part at the interface; and
- (l) machining the joined parts to produce said component.
- 2. Method as described in claim 1 further characterized by:
- the plating material being nickel.
- 3. Method as described in claim 1 further characterized by:
- the plating material being nickel, and applying said nickel by an electroless plating operation.
- 4. Method as described in claim 1 further characterized by:
- (a) the boron nitride having a hexagonal crystalline structure when it is first coated onto the billet; and
- (b) the boron nitride having substantially a hexagonal crystalline structure after said heating in the non-oxidizing atmosphere.
- 5. Method as described in claim 1 further characterized by:
- the step of establishing the first part at a temperature including establishing the first part at a temperature which is determined by relative coefficients of expansion of the two parts such that, when the component is cooled to operating temperatures, the two parts at the interface fit against one another in such a manner that when a desired amount of pressure is applied between the parts at the interface the joint remains stable and the parts do not fracture because of excessive pressure at the interface.
- 6. Method described in claim 5 further characterized by:
- (a) the boron nitride having a hexagonal crystalline structure when it is first coated onto the billet; and
- (b) the boron nitride having substantially a hexagonal crystalline structure after said heating in the non-oxidizing atmosphere.
- 7. Method as described in claim 1 further characterized by:
- (a) the first part being made of an alloy consisting primarily of a Group 8 metal; and
- (b) the second part being made of a metal consisting primarily of titanium.
- 8. Method as described in claim 7 further characterized by:
- (a) the boron nitride having a hexagonal crystalline structure when it is first coated onto the billet; and
- (b) the boron nitride having substantially a hexagonal crystalline structure after said heating in the non-oxidizing atmosphere.
- 9. Method as described in claim 1 further characterized by:
- (a) the first part being made of steel;
- (b) the second part being formed primarily of titanium;
- (c) heating the first part to a temperature below 815.degree. C. prior to applying said forging pressure; and
- (d) heating the to a temperature of between 980.degree. C. and 1100.degree. C.
- 10. Method as described in claim 1 further characterized by:
- coating the billet with a ceramic coating where the billet is not coated with the boron nitride.
- 11. Method as described in claim 10 further characterized by:
- heating the boron nitride coated part in a non-oxidizing atmosphere at a temperature in excess of 600.degree. C.
- 12. Method of forming a component having a rigid joint between a first metal part and a titanium part in a forging operation, comprising the setups of:
- (a) providing the first metal part in a predetermined shape;
- (b) determining an interface between the first part and the titanium part;
- (c) machining the first part into a final form at the interface;
- (d) coating the first part at the interface with a first coating material having a property of inhibiting oxidation during the forging operation with the first coating material being suitable for remaining in the joint at the interface when the component is placed into service;
- (e) coating a billet of titanium, from which the titanium part is to be formed, with boron nitride where the billet is to contact the interface when said forging pressure is applied, the boron nitride having a hexagonal crystalline structure during said coating;
- (f) heating the boron nitride in a non-oxidizing atmosphere at a temperature sufficient for the boron nitride to change from a while state to a black state by heating the billet in said non-oxidizing atmosphere prior to applying said forging pressure thereby changing the boron nitride from a white state to a black state, the boron nitride having substantially a hexagonal crystalline structure after said heating;
- (g) establising the first part at a temperature below that required for plastic deformation during the forging operation;
- (h) heating the billet to a forging temperature;
- (i) placing the first part into a pre-determined position in a forging die;
- (j) placing the billet into a second pre-determined position in the forging die;
- (k) applying forging pressure against the billet thereby forming the billet into the titanium part, and thereby joining the titanium part to the first part at the interface; and
- (l) machining the joined parts to produce said component.
- 13. Method as described in claim 12 further characterized by:
- the first part being primarily aluminum.
- 14. Method as described in claim 12 further characterized by:
- the step of establishing the first part at a temperature establishing the first part at a temperature which is determined by the relative coefficients of expansion of the two parts such that, when the component is cooled to operating temperatures, the two parts at the interface fit against one another in such a manner that when a desired amount of pressure is applied between the parts at the interface the joint remains stable and the parts do not fracture because of excessive pressure at the interface.
- 15. Method as described in claim 14 further characterized by:
- heating the boron nitride coated billet to a temperature in excess of 600.degree. in a non-oxidizing atmosphere prior to the application of forging pressure.
- 16. Method as described in claim 15 further characterized by:
- coating the billet with a ceramic coating where the billet is not coated with the boron nitride.
Parent Case Info
CROSS-REFERENCE TO RELATED APPLICATION
This is a continuation-in-part to U.S. application Ser. No. 498,347, filed May 26, 1983, now U.S. Pat. No. 4,608,742.
US Referenced Citations (21)
Foreign Referenced Citations (6)
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248601 |
Oct 1962 |
AUX |
8326 |
Mar 1980 |
EPX |
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Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
498347 |
May 1983 |
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