| 摘要 |
A method for producing a composite spark plug electrode is disclosed. The method comprises forming a first metal into a cup having an open end, a closed end and a wall surrounding a central opening which extends a distance z from the closed end to the open end. The method also comprises forming, from a second and different metal, a right circular cylindrical core sized to be received in the central opening in close fitting relationship with the wall therearound, and extending from the closed end toward the open end a distance less than z, and positioning the core in the central opening, thereby forming a composite billet having first and second ends corresponding, respectively, with the open and closed ends of the cup. Finally, a portion of the composite billet is extruded, second end first, through an extrusion orifice of a die with a force applied to the first end of the composite billet by an end of a tool. The force is applied so as to maintain substantial contact between the core and the closed end of the cup while extrusion is occurring.
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