Precision forming of titanium alloys and the like by use of induction heating |
|||||||
| 申请号 | US3584487D | 申请日 | 1969-01-16 | 公开(公告)号 | US3584487A | 公开(公告)日 | 1971-06-15 |
| 申请人 | CARLSON ARNE H; | 发明人 | CARLSON ARNE H; | ||||
| 摘要 | Titanium alloy blanks or the like are successively coated with a high-temperature lubricant; preheated, e.g. in a preheat oven or in the forming machine, to a forming temperature (about 1000 1775* F.); precision formed into a desired shape in a press which includes inductively heated forming tools, serving to maintain the metal at the forming temperature throughout the forming operation; and slowly cooled, e.g. first in a postheat oven down to a lower elevated temperature (e.g. about 600* F.) and then down to ambient temperature under cover of an asbestos blanket or the like. The heat-forming tools include a fixed die, a movable die and a movable clamping pad. The movable tools are mounted for precision movement by leader pins and bushings. Insulation and water jackets are interposed between the heated tools and the leader pins and bushings to prevent harmful heating of the latter. The forming tools comprise water-cooled tubular conductors embedded in insulative material which in turn is embedded in die parts of long life metals on which the forming surfaces are machined or embedded in supporting cores therefor. | ||||||
| 权利要求 | 2. The method of claim 1, including circulating a cooling fluid through at least a portion of the region containing the inductively heated forming tools and the guide pins and bushings, to remove heat from such region which, if not removed, would tend to harmfully heat such guide pins and bushings. 3. The method of claim 1, further comprising preheating the blank to about its forming temperature before placing it in the forming press. 4. The method of claim 1, further comprising preheating the blank to about its forming temperature in a substantially air-free atmosphere before placing it in the forming press. 5. The method of claim 1, further comprising coating the blank with a high temperature lubricant before placing it in the forming press, said lubricant serving to facilitate some slippage of the clamped portion of the blank during its forming. 6. The method of claim 5, further comprising preheating the coated blank in a substantially nitrogen-free atmosphere. 7. The method of claim 1, comprising slowing cooling the formed part to prevent severe surface cracking. 8. The method of claim 7, comprising slowly cooling the formed part in a substantially air-free atmosphere. 9. The method of claim 7, comprising cooling the formed part by first placing it in a heated confined zone the temperature of which is below the forming temperature but above ambient temperature, allowing it to slowly and naturally cool in said zone down to the temperature of the zone, and then placing such part in a nonheated zone and allowing it to slowly and naturally cool in said zone down to ambient temperature. 10. The method of claim 1, applied to a titanium metal containing blank and wherein the forming tools are inductively heated to a temperature enabling them to conductively heat the blank to about 1000*-1775* F. 11. A method of forming a part from a sheet metal blank in a forming press which includes a fixed forming tool and two movable forming tools supported for movement along a path bordering the fixed forming tool, comprising: placing a first portion of the blank between the two movable forming tools and an adjacent second portion of the blank in position tO contact the fixed forming tool; moving the two movable forming tools relatively together to firmly hold the first portion of said blank between them; inductively heating each of said forming tools to a temperature sufficient to cause them to in turn conductively heat the blank and maintain it at forming temperature, including heating the two movable tools, and hence the held portion of the blank, to a higher temperature than the fixed forming tool and the unheld portion of the blank which is heated thereby; and moving the two movable forming tools and the blank held between them, as an assembly, relatively towards the fixed forming tool, and the blank against such tool, at a rate causing plastic deformation of the blank attended by no appreciable strain hardening, with the greater heating of the held portion causing more material flow to occur in such portion than in the lower temperature unheld portion of the blank, resulting in a minimization of thinning in the contoured region of the finished part. 12. The method of claim 11, wherein a titanium alloy blank is used and the forming tools are inductively heated to a temperature enabling them to conductively heat the blank to about 1000*-1775* F., and a 25*-200* F. temperature differential is maintained between the portions of the blank heated by the movable and fixed tools. 13. The method of claim 12, wherein the titanium alloy is temperable and said method includes heating the formed part to a suitable temperature for hardening and then while still hot quenching it in water of the like. 14. The method of claim 11, further comprising coating the blank with a high-temperature lubricant and preheating it to about its forming temperature, said lubricant serving both as a protective coating, to protect the metal against corrosion, and as a lubricant to facilitate some slippage of the held portion of the blank during forming. 15. Sheet metal forming equipment comprising: a first bolster plate; a plurality of spaced-apart leader pins, each of which is firmly secured at one of its ends to said first bolster plate and extends away from said plate, in parallelism with each other leader pin; a first forming tool assembly secured to said bolster plate on the same side thereof as said leader pins, said assembly including an inductively heatable mass, an induction heating coil surrounding a portion of said mass, a die part on said mass, and heat barrier means interconnected between said mass and said bolster plate; and a second bolster plate including bushing means mounting it for precision movement along said leader pins; a second-forming tool assembly secured to said second bolster plate, on the side thereof facing the first forming tool assembly, and comprising an inductively heatable mass, and induction heating coil surrounding a portion of said mass, a die part on said mass, and heat barrier means interconnected between said heated mass and said bolster plate, said heat barrier means extending between said mass and said bushing means for protecting the bushing means against overheating, with the die part of the second forming tool assembly cooperating with the die part of the first forming tool assembly when the bolster plates are moved relatively together to impress a shape into a sheet metal blank inserted between them. 16. The sheet metal forming equipment of claim 15, wherein each said induction heating coil comprises electrical conductors of tubular form, so that a cooling fluid can be circulated through them. 17. The sheet metal forming equipment of claim 15, wherein said equipment further comprises a third forming tool assembly interposed between said first and second bolster plates and including: a bushing housing for each leader pin, said housings containing guide bushings which surroundingly engage said leader pins; support means rigidly interconnecting said bushing housings; and a third forming tool assembly secured to said support means, on the side thereof forming the second forming tool assembly, and comprising an inductively heatable mass, a die part on said mass, and an induction heating coil surrounding a portion of said mass, with said leader pins, guide bushings, the second bolster plate and said support means serving to mount the second and third forming tool assemblies for precision movement along a path bordering the first-forming assembly. 18. The sheet metal forming equipment of claim 17, further comprising first, second and third independently controllable means for supplying electrical energy to the induction heating coils of said first, second and third forming tool assemblies, enabling the second and third assemblies to be control heated at a higher temperature than the first assembly. 19. The sheet metal forming equipment of claim 15, wherein each said heat barrier means includes a coolant jacket containing passageways through which a cooling fluid may be flowed. 20. The sheet metal equipment of claim 15, wherein each said forming tool assembly comprises sidewall means, and said heat barrier means comprises insulative material interposed between said sidewall means and the forming tool. 21. The sheet metal equipment of claim 20, wherein said bushing means comprise sleeve members situated outwardly of, and rigidly secured to, the sidewall means of said second forming tool assembly. 22. The sheet metal forming equipment of claim 15, in combination with a forming press including a fixed platen, a movable platen, and means for removably securing one of said bolster plates to one of said platens and the other bolster plate to the other platen. 23. The sheet metal forming equipment of claim 17, wherein said first bolster plate includes at least one support pin opening extending through it in parallelism with said leader pins, and said equipment further includes: a support pin extending through said opening, and at one end containing the support means of said third forming tool assembly; a first piston-cylinder motor connected to said second bolster plate, for moving it towards and away from said first bolster member; and a second piston-cylinder motor for moving said third forming tool assembly through the intermediary of said support pin. 24. Sheet metal forming equipment comprising: a fixed forming tool and two movable forming tools supported for movement with a clamped portion of a sheet metal blank between them along a path bordering the fixed forming tool, with each said forming tool comprising a die member and an induction heating coil associated with said member; and first, second and third independently controllable means for supplying electrical energy to the induction heating coils of said fixed and said two movable forming tools, enabling the two movable die members to be control heated at a higher temperature than the fixed die member. 25. Sheet metal forming equipment according to claim 24, wherein each die member comprises an inductively heatable mass, and wherein each induction heating coil surrounds a portion of said mass, with said induction heating coils in use inductively heating said masses, and with said die members conductively heating material to be formed which is in contact with said members. 26. Sheet metal forming equipment according to claim 24, wherein each induction heating coil comprises electrical conductors of tubular form, so that a cooling fluid can be flowed through them, and wherein said equipment further comprises means for delivering a cooling fluid into said conductors. |
||||||
| 说明书全文 | |||||||
QQ群二维码
意见反馈
意见反馈