TWI283609B - Cold-forming of molybdenum by backward extrusion - Google Patents

Abstract

A method for the cold-forming of molybdenum by backward extrusion includes that a complete recrystallization is performed before the cold-forming.

Description

1283609 Forms a sharp edge on the extrusion die. This is intended to prevent discontinuities in tension transmission after reshaping. However, the method proposed therein is practically applied only in the case of a TZM alloy, and it can be used at best to manufacture a partially crack-free machine body (see example). SUMMARY OF THE INVENTION A method of cold forming molybdenum by reverse extrusion is described in the present application. Surprisingly, despite the brittleness of molybdenum, we have found that the material can be re-formed by reverse extrusion without cracks and fractures. In this extrusion method the energy is applied in the form of compressive strain. Prior to this step, the molybdenum is completely recrystallized by heat treatment by passing the point of relief of the material when the tension is sufficiently low. Recrystallization is intended to eliminate any and all of the lattice tension previously produced by reshaping. Then, although only a relatively low force is applied, the material still reaches its point of relief. Preferably, the temperature is above 13 〇 (rc, especially above 14 ( (the melting point of molybdenum is 2623 _5. 〇 is recrystallized. Therefore) the present invention relates to a method of performing complete recrystallization followed by reverse squeezing. A method of forming a molybdenum and forming the molybdenum. The method is preferably carried out in the following manner: = degree is higher than UOOMUM or - protective gas is completely, ', :: 曰 - has a diameter at the end The molybdenum wire in the diameter range of the finished product is cooled in the air or in a protective gas, and then the material W after the crystallization at room temperature becomes a rotationally symmetrical pre-made part. The basic advantages of the method are as follows : First of all, the material is used better than the deeper; in addition, =η has this part of the hunter formed by reverse extrusion to form a thicker or profiled bottom than the 96014.doc 1283609. The method is also applicable to other brittle metals or Its alloy, for example, chromium or tungsten. On an industrial scale, the method can be used, for example, to manufacture materials for lighting engineering. Part of the process can be used to conduct current through glass or ceramics. light bulb Partially, and can be used as an emitter electrode in CCFL (c〇id (10) edge fluores-cent lighting, cold cathode fluorescent lighting) or cold cathode lamp (German: Kaltkathodenlampen, KKL). The following specific examples illustrate in more detail. The invention is not limited in scope. The term ''deep extension" means reforming to form a hollow body by tensile stress of a metal sheet or forming a hollow body from a larger circumference a hollow body of the circumference. The thickness of the metal sheet is not intentionally changed during the curing process. First, the pre-cut sheet is placed in the container, and then the sheet is pressed onto the extension mold while holding the downward clamp, and thus Preventing the formation of creases during the deep extension press process. The descending extension punch presses the sheet into the extension die 'i to form it into the desired workpiece. When the extension ratio is high, the depth can be deepened in several steps The extension ratio is the ratio of the diameter of the pre-cut metal piece to the diameter of the workpiece. The deep drawing step may include an intermediate annealing step. Hanging pressure system - manufacturing hollow or solid body cold Forming method. The sturdy preparatory material or the extrusion material is extruded through a die (forward) by an extensor or the extensor is pressed into the preparation material to cause the material to be reversed along the excavator. Flow. This differs from extrusion in that the processing temperature and the extrusion process are used to make a single part rather than a semi-finished extruded product, which makes it possible to produce products of complex shapes. The advantages of this method include its tooling into 960l4. .doc 1283609 This is low, long tool life and high operating rate (output rate is about 3〇~150 pieces per minute). Excellent surface quality and suitable for further surface treatment. Aluminum alloy is the main application field. Cold cathode 4 The CCFL lamp is a glory lamp that utilizes the principle of discharge at low voltage. This discharge excites the diluted mixed gas (for example, Ar/Hg). To free the gas and make it electrically conductive, a high voltage is initially applied to the tube without heating the electrodes. The electrical energy excites the gas atoms, which in turn emit excess energy in the form of UV (ultraviolet light) and visible light. A phosphorus-based coating inside the tube converts 1; ¥ radiation into visible light. The electrodes are made of refractory metal and are usually made of molybdenum. Molybdenum is particularly suitable because it is easy to emit electrons. Operating with alternating current, the electrodes operate alternately as a cathode and an anode. [Embodiment] A cover is formed by a 1 mm molybdenum wire on a press by reverse extrusion at room temperature under a pressure of about 1500 MPa, wherein the molybdenum wire has been greater than 1,400 C. Recrystallized in a vacuum and cooled in a vacuum. Such a cover can be used as an emitter electrode in a CCFL lamp. According to the described method, the material can be completely reshaped without waste. A microscopic longitudinal section of a cover is produced by this method as shown in Fig. 1. This method can be used to manufacture machined parts without cracks and rotational symmetry. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 shows a longitudinal section of a molybdenum cover made in accordance with the method of the present invention, in a ratio of 50:1. 96〇l4.d〇c

Claims (1)

• Patent Application No. 093128875 Replaces the scope of patent application in Chinese (96, 20, and the scope of patent application: 1. The cold forming method of the seedling is characterized in that it is completely re-formed before being cold-formed by reverse extrusion.曰曰2·If the method of claim 1, 1, is specifically for recrystallization in a protective gas and/or vacuum. 3 As in the method of claim 1, the direct 彳 为 is greater than 13 〇〇 Recrystallization is carried out at a temperature. 4. The method of claim 1, characterized in that: Α) - the molybdenum workpiece is completely recrystallized in a vacuum and/or a shielding gas at a temperature greater than 14 〇〇t; Cooling the workpiece in a vacuum and/or a shielding gas; C) extruding the cross section of the recrystallized workpiece at room temperature to produce a finished part. 5. The method of claim 4 wherein the finished portions are extruded to be rotationally symmetrical on the outer shape. 6. Use of an extruder workpiece made of molybdenum obtained by the method of claim 1 in a lighting project. 7. The use of claim 6 for the manufacture of a conducting current through a portion of a glass or ceramic bulb or for the fabrication of a transmitting electrode in a CCFL or cold cathode lamp. 96014-960209.doc