Method and apparatus for induction heat treatment of structural members
AssigneeThe Boeing Company
InventorsLee C. Firth, John R. Fischer, Paul S. Gregg, Marc R. Matsen
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Abstract
An apparatus and method for heat treating a structural member, for example, to relieve stresses therein, are provided. The structural member is restrained in a die cavity by one or more inflatable bladders so that a desired dimensional accuracy is achieved. The structural member can be heated by an electromagnetic field generator, such as an induction coil, that heats one or more susceptors to a characteristic Curie temperature. The apparatus can be used to process structural members of various sizes and shapes, and the heating and cooling cycle can be performed relatively quickly.
Claims28
An apparatus for heat treating a structural member, the apparatus comprising:
- first and second co-operable dies structured to define a die cavity therebetween for at least partially receiving the structural member;
- at least one susceptor in thermal communication with said die cavity, each susceptor having a Curie temperature at which said susceptor becomes paramagnetic;
- an electromagnetic field generator configured to induce a current within at least a portion of said at least one susceptor;
- at least one bladder positioned in said die cavity, each said bladder configured to receive a pressurized fluid for expanding said bladder;
- and
- at least one rigid tool disposed in said die cavity, said tool defining a contour surface corresponding to the structural member,
- wherein said at least one bladder is configured to urge said at least one tool against the structural member and thereby restrain a distortion of the structural member while the structural member is heat treated.
A method of heat treating a structural member, the method comprising:
- providing the structural member at least partially in a die cavity;
- positioning at least one bladder in the die cavity proximate to the structural member;
- positioning at least one tool in the die cavity proximate to the structural member, each tool defining a surface corresponding to at least a portion of the structural member;
- injecting a pressurized fluid into the at least one bladder and thereby expanding the bladder to at least partially fill a space in the die cavity and restrain the structural member in a predetermined configuration against the corresponding surface of the at least one tool;
- and
- energizing an electromagnetic field generator to induce a current within at least a portion of at least one susceptor, thereby heating the structural member to a heat treatment temperature,
- wherein the structural member is restrained by the at least one bladder during at least part of said energizing step such that the bladder restrains a distortion of the structural member.
Dependencies are inferred from the claim text.