초록 ▼

In a method of forming a hollow workpiece having open ends by inner pressure in a multi-part forming tool, the forming tool having a forming mold is heated and the workpiece is placed into the forming mold of the forming tool. Closing plugs are inserted into the open ends of the workpiece, wherein t

In a method of forming a hollow workpiece having open ends by inner pressure in a multi-part forming tool, the forming tool having a forming mold is heated and the workpiece is placed into the forming mold of the forming tool. Closing plugs are inserted into the open ends of the workpiece, wherein the closing plugs are components of closing cylinders, in order to seal off the open ends. The forming tool is closed. A heated pressure fluid is introduced into the hollow workpiece through at least one of the closing plugs, with the hollow workpiece having been heated and plasticized in the forming tool. The material of the hollow workpiece is pressed with the heated pressure fluid into the forming mold of the forming tool. The device for performing the method has a multi-part forming tool with a forming mold for the workpiece. Hydraulic closing cylinders with closing plugs are provided for sealing the open ends of the workpiece. The forming tool has a heating device for heating at least the forming mold. Heated pressure fluid is introduced into the workpiece through at least one of the closing plugs.

대표청구항 ▼

1. A method of forming a hollow workpiece having open ends by inner pressure in a multi-part forming tool, the method comprising the steps of:heating a forming tool having a forming mold; placing the workpiece of aluminum or an aluminum alloy into the forming mold of the forming tool; inserting clos

1. A method of forming a hollow workpiece having open ends by inner pressure in a multi-part forming tool, the method comprising the steps of:heating a forming tool having a forming mold; placing the workpiece of aluminum or an aluminum alloy into the forming mold of the forming tool; inserting closing plugs into the open ends of the workpiece to seal off the open ends, wherein the closing plugs are components of closing cylinders, and closing the forming tool; introducing nitrogen as a heated pressure fluid into the hollow workpiece through at least one of the closing plugs which has been heated via the forming tool, the hollow workpiece having been heated and plasticized; pressing at a temperature of between 250.degree. C. and 350.degree. C. and at an inner pressure of between 180 bar and 250 bar the material of the hollow workpiece with the heated nitrogen into the forming mold of the forming tool; and adjusting the inner pressure by a control valve, provided in a supply line for the nitrogen, as a function of a heating temperature of the workpiece and the heating temperature of the forming tool.