Preparation method of ultra-thin-wall special-shaped molybdenum sleeve

Abstract

The application discloses a preparation method of an ultrathin-wall special-shaped molybdenum sleeve, and belongs to the technical field of molybdenum sleeve preparation.The method comprises the following steps: 1, cutting a cold-rolled molybdenum foil to obtain a cut molybdenum foil; 2, winding and fixing the cut molybdenum foil on a core rod; 3, die pressing the fixed cut molybdenum foil together with the core rod to form a molybdenum pipe blank; 4, performing a shaping vacuum annealing on the molybdenum pipe blank together with the core rod to form a molybdenum pipe; 5, laser welding the molybdenum pipe to obtain a molybdenum pipe piece; 6, forming the molybdenum pipe piece into a special-shaped molybdenum pipe through a special forming die; and 7, cutting to obtain the ultrathin-wall special-shaped molybdenum sleeve.The ultrathin-wall special-shaped molybdenum sleeve prepared by the method has the advantages of bright inner and outer surfaces, small roughness, good consistency, high dimensional precision, high density, good mechanical properties, small energy consumption in the preparation process, low machining difficulty, low cost, high product yield, and the like, and is suitable for target material, hot-couple protection sleeves and sleeve fields for the electronic industry.

Description

Technical Field

[0001] This invention belongs to the field of molybdenum tube forming technology, specifically relating to a method for preparing an ultrathin-walled irregularly shaped molybdenum sleeve. Background Technology

[0002] Molybdenum (Mo) itself possesses characteristics such as a high melting point, low high-temperature creep rate, good thermal shock resistance, and high high-temperature strength. It also exhibits good electrical and thermal conductivity, a low coefficient of expansion, and a low sputtering rate. Due to its high-temperature resistance, it is widely used in the nuclear industry, furnace materials, and aerospace. Molybdenum tubes are mainly used in target materials, thermocouple protective sleeves, and sleeves in the electronics industry. The commonly used industrial processing method for molybdenum tubes involves first preparing the molybdenum tube, followed by machining. Common methods for preparing molybdenum tubes include extrusion, forging, and hot isostatic pressing. Patent US20060042728A1 discloses a method for producing tubular Mo targets with uniform grain size and texture. Mo powder is pressed into shape under a pressure of 200–250 MPa, sintered into a billet at 1780–2175 °C, then machined into a tube blank, and finally extruded and annealed to obtain a uniformly structured tubular Mo target. Patent 200810104986.1 discloses a method for preparing high-density molybdenum tubes. The method involves isostatically pressing molybdenum powder with a purity >3N and a particle size of 1–10 μm at 160–220 MPa, then holding it in a medium-frequency furnace at 1600–2000℃ for 1–8 hours, followed by sintering under a hydrogen protective atmosphere to prepare a ring-shaped molybdenum tube blank with a density of 9.5–9.9 g / cm³. 3 Then, it is forged at 700–1500℃, and formed when the deformation reaches 40–80%, producing a high-density molybdenum tube blank. This blank is then extruded at 700–1500℃ using an extruder, achieving a density of 9.9–10.2 g / cm³. 3 After stress relief by holding the material at 700–1200℃ for 1–5 hours, it undergoes machining, cleaning, and drying to obtain a high-density molybdenum tube. While all the above methods can produce molybdenum tubes, which are then machined to obtain molybdenum sleeves, they generally suffer from long machining times, low yields, poor surface finish inside and outside the tube, low material density, and weak mechanical properties. Summary of the Invention

[0003] The technical problem to be solved by this invention is to provide a method for preparing ultrathin-walled shaped molybdenum sleeves, addressing the shortcomings of the prior art. This method uses cold-rolled molybdenum foil as raw material. First, the molybdenum foil is molded into a molybdenum tube using a combination of molding and vacuum annealing. Then, through shaping, an ultrathin-walled shaped molybdenum sleeve is obtained. This molybdenum sleeve has bright inner and outer surfaces, low roughness, good consistency, high dimensional accuracy, high density, and good mechanical properties. Furthermore, the manufacturing process has low energy consumption, low machining difficulty, low cost, and high yield, solving the problems of long machining time, low yield, low surface finish, low material density, and weak mechanical properties in existing molybdenum sleeve manufacturing processes.

[0004] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a method for preparing an ultrathin-walled irregularly shaped molybdenum sleeve, characterized in that the method includes the following steps:

[0005] Step 1: Cut the cold-rolled molybdenum foil to obtain cut molybdenum foil;

[0006] Step 2: Wrap the cut molybdenum foil obtained in Step 1 along its length and fix it onto the core rod;

[0007] Step 3: Press the cut molybdenum foil fixed in Step 2 together with the core rod to form a molybdenum tube blank on the core rod;

[0008] Step 4: Place the molybdenum tube blank formed in Step 3, along with the mandrel, into a shaping mold for shaping and vacuum annealing to form a molybdenum tube on the mandrel;

[0009] Step 5: Remove the molybdenum tube formed in Step 4 from the core rod, and then perform laser welding on the gap at the connection of the molybdenum tube to obtain the molybdenum tube fitting;

[0010] Step 6: Apply lubricating oil evenly to the inner and outer surfaces of the molybdenum tube obtained in Step 5, then install it on the shaped mandrel, and connect and fix one end to the shaped mandrel. Pull the shaped mandrel at the fixed end, so that the shaped mandrel and the molybdenum tube will pass through the shaped forming mold multiple times under the pressure of the pressure block to form the shaped molybdenum tube.

[0011] Step 7: Use laser cutting to cut the irregular molybdenum tube obtained in Step 6 to obtain an ultra-thin-walled irregular molybdenum sleeve.

[0012] The above-mentioned method for preparing an ultrathin-walled irregularly shaped molybdenum sleeve is characterized in that the thickness of the cold-rolled molybdenum foil in step one is 0.03mm to 0.1mm; the length of the cut molybdenum foil is 100mm greater than the length of the target product molybdenum sleeve, and the width is 0.5mm to 2mm greater than the circumference of the target product molybdenum sleeve. This invention, by selecting a cold-rolled molybdenum foil with a thickness of 0.03mm to 0.1mm, ensures that during subsequent molding and vacuum annealing, the thickness will not be unsuitable, preventing the molybdenum material from having too little or too much springback, thus ensuring the sleeve cannot be formed or shaped. By limiting the width of the cut molybdenum foil, a certain circumference allowance is left for subsequent laser welding and irregular shaping, thereby better controlling the outer diameter accuracy of the ultrathin-walled irregularly shaped molybdenum sleeve. By controlling the length to leave allowance for subsequent cutting, the accuracy of the length dimension is ensured.

[0013] The above-mentioned method for preparing an ultrathin-walled irregularly shaped molybdenum sleeve is characterized in that the core rod in step two is a stainless steel rod, the length of which is the same as the length of the cut molybdenum foil, and the diameter of the core rod is 0.3 mm to 1 mm smaller than the diameter of the target product molybdenum sleeve. This invention, by limiting the core rod diameter to be 0.3 mm to 1 mm smaller than the diameter of the target product molybdenum sleeve, ensures that the springback force of the material itself is counteracted during the tube forming process, thereby improving the forming accuracy of the molybdenum tube.

[0014] The above-mentioned method for preparing an ultrathin-walled shaped molybdenum tube is characterized in that the molding process in step three is carried out using a 50-ton hydraulic press, with a molding force of 10 to 35 tons. The molding begins at the point where the molybdenum foil is wound and fixed on the mandrel, and the mandrel rotates 30° to 60° with each molding cycle. This invention, by starting molding from the point where the molybdenum foil is wound and fixed on the mandrel and controlling the rotation angle of the mandrel during molding, employs a multi-stage molding method to evenly distribute the springback force, thereby better controlling the diameter accuracy of the molybdenum tube blank and laying a good foundation for subsequent shaping and vacuum annealing. Simultaneously, it avoids scratches during molding, which would affect the surface quality of the molybdenum tube blank.

[0015] The method for preparing an ultrathin-walled shaped molybdenum tube described above is characterized in that the temperature of the shaping vacuum annealing in step four is 800℃~1000℃. The shaping vacuum annealing process at this temperature effectively eliminates the stress from the molding process, ensuring that the shaped molybdenum tube does not deform, which is beneficial for subsequent laser welding. Simultaneously, at this temperature, the molybdenum tube will not recrystallize, preventing material embrittlement and avoiding brittle fracture during subsequent shaped forming processes. It also eliminates internal stress in the molybdenum tube to reduce springback, ensuring the smooth progress of the shaped forming process.

[0016] The above-mentioned method for preparing an ultrathin-walled shaped molybdenum sleeve is characterized in that the speed at which the shaped mandrel is pulled in step six is ​​10 mm / s to 50 mm / s, and the pressure of the pressing block is 1 ton to 5 tons. This invention improves the forming accuracy of the ultrathin-walled shaped molybdenum sleeve by controlling the speed of pulling the shaped mandrel and the pressure of the pressing block, without causing the molybdenum tube to break.

[0017] The above-mentioned method for preparing an ultrathin-walled shaped molybdenum sleeve is characterized in that, in step seven, the ultrathin-walled shaped molybdenum sleeve has an outer diameter of 3mm to 10mm, an outer diameter accuracy of ±0.1mm, a wall thickness of 0.03mm to 0.1mm, a length of 1000mm or more, an inner and outer surface finish Ra < 0.3μm, and a density greater than 10.2g / cm³. 3 .

[0018] Compared with the prior art, the present invention has the following advantages:

[0019] 1. This invention uses cold-rolled molybdenum foil as raw material. First, the molybdenum foil is molded into a molybdenum tube using a combination of molding and vacuum annealing. Then, through a special forming process, an ultra-thin-walled shaped molybdenum sleeve is obtained. The density of this ultra-thin-walled shaped molybdenum sleeve is greater than 10.2 g / cm³. 3 It is far superior to molybdenum sleeves prepared by conventional pressing, sintering, and extrusion methods, and has high forming precision and excellent mechanical properties.

[0020] 2. In this invention, the molding process of cutting molybdenum foil into molybdenum tube blanks and the process of shaping molybdenum tubes are both cold forming processes. Compared with conventional sintering and other forming processes, this process has the advantage of low energy consumption and low machining difficulty, which reduces the preparation cost of thin-walled irregularly shaped molybdenum tubes.

[0021] 3. The molding process of this invention generates only a small amount of waste material, with no turning or oxide scale production, reducing material loss and improving the yield of thin-walled irregularly shaped molybdenum sleeves.

[0022] 4. The ultra-thin wall molybdenum sleeve prepared by this invention has an outer diameter of 3mm to 10mm, an outer diameter accuracy of ±0.1mm, a wall thickness of 0.03mm to 0.1mm, a length of more than 1000mm, and an inner and outer surface finish Ra < 0.3μm. Its inner and outer surfaces are bright, with low roughness, good consistency, high dimensional accuracy, and easy wall thickness adjustment. It is suitable for fields such as target materials, thermocouple protective sleeves, and sleeves used in the electronics industry.

[0023] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of how molybdenum foil is cut and wound along its length and fixed onto a core rod in this invention.

[0025] Figure 2 This is a schematic diagram of the molding of the fixed, cut molybdenum foil together with the core rod in this invention.

[0026] Figure 3 This is a schematic diagram of the shaping mold in this invention.

[0027] Figure 4 This is a schematic diagram of the irregular-shaped core rod and its connection with the molybdenum tube in this invention.

[0028] Figure 5 This is a schematic diagram of the irregularly shaped core rod and molybdenum tube passing through the irregularly shaped forming mold under the pressure of the pressing block in this invention.

[0029] Figure 6 This is a schematic diagram of the ultra-thin-walled irregularly shaped molybdenum sleeve obtained after cutting in this invention. Detailed Implementation

[0030] Example 1

[0031] This embodiment includes the following steps:

[0032] Step 1: Cut the cold-rolled molybdenum foil with a thickness of 0.03mm to obtain a cut molybdenum foil with a length of 1100mm and a width of 9.92mm;

[0033] Step 2: Wrap and fix the cut molybdenum foil obtained in Step 1 along its length onto a stainless steel core rod with a diameter of 2.7 mm and a length of 1100 mm, as shown below. Figure 1 As shown;

[0034] Step 3: The pre-cut molybdenum foil, fixed in Step 2, along with the core rod, is molded using a 50-ton hydraulic press. Figure 2 As shown, the pressing force of the molding is 10 tons, and the pressing starts from the point where the molybdenum foil is cut and fixed on the core rod. Each time it is pressed, the core rod rotates 30°, forming a molybdenum tube blank on the core rod.

[0035] Step 4: Place the molybdenum tube blank formed in Step 3, along with the mandrel, into the... Figure 3 The shaping mold shown is used for shaping vacuum annealing at a temperature of 800°C to form a molybdenum tube on the mandrel.

[0036] Step 5: Remove the molybdenum tube formed in Step 4 from the core rod, and then perform laser welding on the gap at the connection of the molybdenum tube to obtain the molybdenum tube fitting;

[0037] Step Six: Apply lubricating oil evenly to the inner and outer surfaces of the molybdenum tube obtained in Step Five, then install it on the shaped mandrel, connecting and fixing one end to the mandrel. Figure 4As shown, the irregularly shaped core rod connected to the fixed end is pulled at a speed of 50 mm / s, causing the irregularly shaped core rod and the molybdenum tube to pass through the irregularly shaped forming mold multiple times under the pressure of a 1-ton pressure block driven pulley. Figure 5 As shown, an irregularly shaped molybdenum tube is obtained by molding;

[0038] Step 7: Use laser cutting to cut the irregularly shaped molybdenum tube obtained in Step 6 to separate it from the irregularly shaped core rod, obtaining an ultra-thin-walled irregularly shaped molybdenum sleeve, such as... Figure 6 As shown.

[0039] Testing revealed that the ultrathin-walled shaped molybdenum sleeve prepared in this embodiment has an outer diameter of 3 mm, an outer diameter accuracy of -0.03 mm to +0.02 mm, a wall thickness of 0.03 mm to 0.04 mm, a length of 1000 mm, an inner and outer surface finish Ra = 0.27 μm, and a density of 10.25 g / cm³. 3 .

[0040] Example 2

[0041] This embodiment includes the following steps:

[0042] Step 1: Cut the cold-rolled molybdenum foil with a thickness of 0.1mm to obtain a cut molybdenum foil with a length of 1600mm and a width of 33.42mm;

[0043] Step 2: Wrap and fix the cut molybdenum foil obtained in Step 1 along its length onto a stainless steel core rod with a diameter of 9mm and a length of 1600mm. Figure 1 As shown;

[0044] Step 3: The pre-cut molybdenum foil, fixed in Step 2, along with the core rod, is molded using a 50-ton hydraulic press. Figure 2 As shown, the pressing force of the molding is 35 tons, and the pressing starts from the point where the molybdenum foil is cut and fixed on the core rod. Each time it is pressed, the core rod rotates 60°, forming a molybdenum tube blank on the core rod.

[0045] Step 4: Place the molybdenum tube blank formed in Step 3, along with the mandrel, into the... Figure 3 The shaping mold is used for shaping vacuum annealing at a temperature of 1000℃ to form a molybdenum tube on the core rod.

[0046] Step 5: Remove the molybdenum tube formed in Step 4 from the core rod, and then perform laser welding on the gap at the connection of the molybdenum tube to obtain the molybdenum tube fitting;

[0047] Step Six: Apply lubricating oil evenly to the inner and outer surfaces of the molybdenum tube obtained in Step Five, then install it on the shaped mandrel, connecting and fixing one end to the mandrel. Figure 4As shown, the irregularly shaped core rod connected to the fixed end is pulled at a speed of 10 mm / s, causing the irregularly shaped core rod and the molybdenum tube to pass through the irregularly shaped forming mold multiple times under the pressure of the 5-ton pressure block drive pulley. Figure 5 As shown, an irregularly shaped molybdenum tube is obtained by molding;

[0048] Step 7: Use laser cutting to cut the irregularly shaped molybdenum tube obtained in Step 6 to separate it from the irregularly shaped core rod, obtaining an ultra-thin-walled irregularly shaped molybdenum sleeve, such as... Figure 6 As shown.

[0049] Testing revealed that the ultrathin-walled shaped molybdenum sleeve prepared in this embodiment has an outer diameter of 10 mm, an outer diameter accuracy of -0.02 mm to +0.08 mm, a wall thickness of 0.1 mm to 0.12 mm, a length of 1500 mm, an inner and outer surface finish Ra = 0.26 μm, and a density of 10.23 g / cm³. 3 .

[0050] Example 3

[0051] This embodiment includes the following steps:

[0052] Step 1: Cut the cold-rolled molybdenum foil with a thickness of 0.05mm to obtain a cut molybdenum foil with a length of 1300mm and a width of 16.71mm;

[0053] Step 2: Wrap and fix the cut molybdenum foil obtained in Step 1 along its length onto a stainless steel core rod with a diameter of 4.5 mm and a length of 1300 mm. Figure 1 As shown;

[0054] Step 3: The pre-cut molybdenum foil, fixed in Step 2, along with the core rod, is molded using a 50-ton hydraulic press. Figure 2 As shown, the pressing force of the molding is 23 tons, and the pressing starts from the point where the molybdenum foil is cut and fixed on the core rod. Each time it is pressed, the core rod rotates 45°, forming a molybdenum tube blank on the core rod.

[0055] Step 4: Place the molybdenum tube blank formed in Step 3, along with the mandrel, into the... Figure 3 The shaping mold shown is used for shaping vacuum annealing at a temperature of 950°C to form a molybdenum tube on the mandrel.

[0056] Step 5: Remove the molybdenum tube formed in Step 4 from the core rod, and then perform laser welding on the gap at the connection of the molybdenum tube to obtain the molybdenum tube fitting;

[0057] Step Six: Apply lubricating oil evenly to the inner and outer surfaces of the molybdenum tube obtained in Step Five, then install it on the shaped mandrel, connecting and fixing one end to the mandrel. Figure 4As shown, the irregularly shaped core rod connected to the fixed end is pulled at a speed of 25 mm / s, causing the irregularly shaped core rod and the molybdenum tube to pass through the irregularly shaped forming mold multiple times under the pressure of the 3-ton pressure block drive pulley. Figure 5 As shown, an irregularly shaped molybdenum tube is obtained by molding;

[0058] Step 7: Use laser cutting to cut the irregularly shaped molybdenum tube obtained in Step 6 to separate it from the irregularly shaped core rod, obtaining an ultra-thin-walled irregularly shaped molybdenum sleeve, such as... Figure 6 As shown.

[0059] Testing revealed that the ultrathin-walled shaped molybdenum sleeve prepared in this embodiment has an outer diameter of 5 mm, an outer diameter accuracy of -0.09 mm to +0.09 mm, a wall thickness of 0.04 mm to 0.06 mm, a length of 1200 mm, an inner and outer surface finish Ra = 0.29 μm, and a density of 10.22 g / cm³. 3 .

[0060] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any way. Any simple modifications, alterations, and equivalent changes made to the above embodiments based on the inventive essence shall still fall within the protection scope of the present invention.

Claims

1. A method for preparing an ultrathin-walled irregularly shaped molybdenum sleeve, characterized in that, The method includes the following steps: Step 1: Cut the cold-rolled molybdenum foil to obtain cut molybdenum foil; Step 2: Wrap the cut molybdenum foil obtained in Step 1 along its length and fix it onto the core rod; Step 3: The cut molybdenum foil fixed in Step 2 is molded together with the core rod to form a molybdenum tube blank on the core rod; Step 4: Place the molybdenum tube blank formed in Step 3, along with the mandrel, into a shaping mold for shaping and vacuum annealing to form a molybdenum tube on the mandrel; Step 5: Remove the molybdenum tube formed in Step 4 from the core rod, and then perform laser welding on the gap at the connection of the molybdenum tube to obtain the molybdenum tube fitting; Step 6: Apply lubricating oil evenly to the inner and outer surfaces of the molybdenum tube obtained in Step 5, then install it on the shaped mandrel, and connect and fix one end to the shaped mandrel. Pull the shaped mandrel at the fixed end, so that the shaped mandrel and the molybdenum tube will pass through the shaped forming mold multiple times under the pressure of the pressure block to form the shaped molybdenum tube. Step 7: Use laser cutting to cut the irregular molybdenum tube obtained in Step 6 to obtain an ultra-thin-walled irregular molybdenum sleeve.

2. The method for preparing an ultrathin-walled irregularly shaped molybdenum sleeve according to claim 1, characterized in that, The thickness of the cold-rolled molybdenum foil mentioned in step one is 0.03mm to 0.1mm; the length of the cut molybdenum foil is 100mm longer than the length of the target product molybdenum sleeve, and the width is 0.5mm to 2mm longer than the circumference of the target product molybdenum sleeve.

3. The method for preparing an ultrathin-walled irregularly shaped molybdenum sleeve according to claim 1, characterized in that, The core rod mentioned in step two is a stainless steel rod. The length of the core rod is the same as the length of the molybdenum foil being cut, and the diameter of the core rod is 0.3 mm to 1 mm smaller than the diameter of the target product, the molybdenum sleeve.

4. The method for preparing an ultrathin-walled irregularly shaped molybdenum sleeve according to claim 1, characterized in that, The molding process described in step three is carried out using a 50-ton hydraulic press with a pressing force of 10 to 35 tons. The molding begins at the point where the molybdenum foil is cut and wound and fixed on the core rod. The core rod rotates 30° to 60° with each pressing.

5. The method for preparing an ultrathin-walled irregularly shaped molybdenum sleeve according to claim 1, characterized in that, The temperature for the shaping vacuum annealing described in step four is 800℃~1000℃.

6. The method for preparing an ultrathin-walled irregularly shaped molybdenum sleeve according to claim 1, characterized in that, The speed at which the irregularly shaped core rod is pulled in step six is ​​10 mm / s to 50 mm / s, and the pressure of the pressing block is 1 ton to 5 tons.

7. The method for preparing an ultrathin-walled irregularly shaped molybdenum sleeve according to claim 1, characterized in that, The ultra-thin-walled irregularly shaped molybdenum sleeve mentioned in step seven has an outer diameter of 3mm to 10mm, an outer diameter accuracy of ±0.1mm, a wall thickness of 0.03mm to 0.1mm, a length of 1000mm or more, an inner and outer surface finish Ra < 0.3μm, and a density greater than 10.2g / cm³. 3 .

Images