A platinum-based alloy protective sleeve and preparation method thereof

Abstract

The present invention provides a platinum-based alloy protective sleeve and a preparation method thereof, comprising the steps of vacuum melting, hot forging, plate rolling, tube making, precision drawing, head sealing, calendering and the like. By improving the chemical composition of the dispersant in the raw material and the process, the precision drawing and head sealing processes are improved, so that the surface of the precious metal protective sleeve is bright, the sealing is excellent, the dimensional accuracy of the inner and outer diameters and the wall thickness is high, the service life is long, etc.

Description

Technical Field

[0001] The invention belongs to the technical field of precious metal protection sleeves, and in particular relates to a platinum-based alloy protection sleeve and a preparation method thereof. Background Art

[0002] In the aerospace, chemical industry, solar photovoltaic, special glass, ceramic materials, metal smelting, semiconductor, high temperature gas and other industries and special environments, the temperature sensors or other sensitive devices used need to be isolated from the external medium with precious metal protective sleeves to extend the service life of the temperature sensor, which also puts forward higher requirements on the performance of the precious metal protective tube materials and the processing accuracy of the tubes. The original production process generally uses ordinary precious metal alloy materials, and uses the welding tube billet and natural drawing process. The surface of the precious metal protective sleeve is rough, the straightness is not enough, and the inner and outer diameters and wall thickness are poor. When assembling the sensor, the assembly accuracy is poor and the service life is short. Therefore, it is necessary to develop a precious metal protective sleeve that is resistant to high temperature, oxidation, corrosion, long life, and high dimensional accuracy. Summary of the invention

[0003] In order to solve the problems in the prior art, the present invention provides a platinum-based alloy protective sleeve with high temperature resistance, oxidation resistance, corrosion resistance, high precision and long service life and a preparation method thereof.

[0004] The present invention solves the technical problem by adopting the following technical solutions:

[0005] The first object of the present invention is to provide a method for preparing a platinum-based alloy protective sleeve, which is characterized by comprising the following steps:

[0006] S1. Preparation of platinum-based alloy plate: melting raw materials under a vacuum degree of 1 to 50 Pa, forming the alloy ingot into a platinum-based alloy rolled plate through deformation processes such as hot forging and cold rolling, and subjecting the hot forged alloy plate to homogenization heat treatment at 900 to 1400° C. for 30 to 60 min and then cold rolling, wherein the raw materials include a platinum-based alloy;

[0007] S2, pipe making: bending the rolled plate into a tube shape and then spinning it into a seamless pipe;

[0008] S3, precision drawing: Through the coordinated control of the inner and outer dies, the seamless tube is drawn to obtain a tube blank. During precision drawing, the thickness deformation of the tube wall is 1-10% each time, and the outer diameter of the tube blank after drawing is 2 / 3 of the original;

[0009] S4, head: the head is sealed by spinning process;

[0010] S5. Calendering: Use a high-hardness bright wheel with a precision inner mold to calender the tube blank to obtain a platinum-based alloy protective sleeve;

[0011] The platinum-based alloy is a platinum alloy, a platinum-rhodium alloy, a platinum-iridium alloy or a platinum-gold alloy.

[0012] Furthermore, the raw material also includes a dispersant.

[0013] Furthermore, the mass percentage of each component in the platinum-based alloy is:

[0014] Platinum 70-100%;

[0015] Rhodium 0-30%;

[0016] Iridium 0-30%;

[0017] Gold 0~10%.

[0018] Furthermore, the mass percentage of each component in the platinum-based alloy is:

[0019] Platinum 90-100%;

[0020] Rhodium 0-10%;

[0021] Iridium 0-10%;

[0022] Gold 0~10%.

[0023] Furthermore, the purity of each material in the platinum-based alloy is greater than 99.95%.

[0024] Furthermore, the dispersant is one or more of zirconium, scandium, cerium, yttrium and calcium, and the added amount of the dispersant is less than or equal to 4% of the alloy mass.

[0025] Preferably, the added amount of the dispersant is 0.5% of the alloy mass.

[0026] Furthermore, the platinum-based alloy plate preparation process is as follows:

[0027] 1) Vacuum melting: Under the protection of argon, various materials are placed in a melting furnace according to the proportion, and melted at a vacuum degree of 1 to 50 Pa. After the materials are completely melted, they are kept warm and magnetically stirred for 3 to 6 minutes, and then quickly cast to obtain an ingot;

[0028] 2) Hot forging: placing the ingot in a heat treatment furnace, heat treating at 1100-1450°C for 30-60 minutes and then hot forging; hot forging into an alloy plate, followed by homogenization heat treatment at 900-1400°C for 30-60 minutes; the initial forging temperature during hot forging is 1100-1450°C, and the final forging temperature is 900-1200°C;

[0029] 3) Plate rolling: The hot forged alloy plate is cold rolled for multiple times until the required thickness of the alloy plate is reached, with the deformation amount of each pass being 5% to 15%.

[0030] Preferably, during hot forging, the ingot is placed in a heat treatment furnace, heat treated at 1200-1450°C for 30-60 minutes and then hot forged; hot forged into an alloy plate, and then homogenized heat treated at 1200-1400°C for 30-60 minutes; during hot forging, the initial forging temperature is 1200-1400°C, and the final forging temperature is 900-1200°C.

[0031] Preferably, the initial forging temperature is higher than the final forging temperature.

[0032] Furthermore, the melting temperature during vacuum melting is 1800-2500°C.

[0033] Furthermore, the deformation of the tube wall thickness during each precision drawing is 3-5%.

[0034] Furthermore, the precision drawing is performed at least 4 times.

[0035] Furthermore, the thickness of the tube blank obtained after precision drawing is 1 mm.

[0036] Furthermore, when the spinning process is used to seal the tube, the tube mouth of the tube blank is spun inwardly at an angle of 45°.

[0037] The second object of the present invention is to provide a platinum-based alloy protection sleeve made by the above preparation method.

[0038] Furthermore, the protective sleeve is used for precious metal material temperature sensors and other sensitive components.

[0039] Compared with the prior art, the beneficial technical effects of the present invention are:

[0040] The present invention improves the chemical composition and process of the dispersant in the raw material, so that the dispersant is dispersed and distributed in the metal matrix to enhance toughness, hinder grain boundary sliding and grain growth, and make the precious metal protection tube resistant to high-temperature oxidation, ablation, and high-temperature airflow erosion, etc., with excellent high-temperature mechanical properties and long service life; the hot forging process, precision drawing, and head sealing process are improved, so that the surface of the precious metal protection tube is bright, the inner and outer diameters and wall thicknesses are uniform, and the assembly accuracy is high. The head obtained by spinning the head has good sealing performance, is safe and reliable, and the protection tube sleeve has good high temperature resistance and corrosion resistance, which effectively guarantees the functionality and service performance of the temperature sensor and other sensitive components; the platinum-based alloy protection sleeve of the present invention has good high temperature resistance, corrosion resistance, and oxidation resistance. The improvement of the chemical composition of the dispersant in the raw material and the hot forging, precision drawing and other processes is conducive to improving the service life of the temperature sensor and other sensitive components.

[0041] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented according to the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are listed below. DETAILED DESCRIPTION

[0042] The technical solution of the present invention is further described in detail below in conjunction with specific embodiments. It should be understood that the following embodiments are only exemplary illustrations and explanations of the present invention and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are included in the scope that the present invention is intended to protect.

[0043] In addition, unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0044] Example 1

[0045] 1) Select single platinum with a purity of ≥99.95%, the mass percentage of platinum in the alloy is 99.5%, and the dispersant is one or more of zirconium, scandium, cerium, and yttrium with a mass percentage of 0.5%, wherein zirconium is 0-0.5%; scandium is 0-0.5%; cerium is 0-0.5%; yttrium is 0-0.5%; calcium is 0-0.5%; purity ≥99.95%;

[0046] 2) Vacuum medium frequency melting:

[0047] Step 1) placing the ingredients of each substance in a melting furnace, melting them under a vacuum degree of 1 to 50 Pa, filling them with argon gas for protection, and the melting temperature is 1850 to 1950° C. After each material is completely melted, magnetic stirring is performed to uniformly keep the temperature for 3 minutes, and then rapid casting is performed to obtain an ingot;

[0048] 3) Hot forging:

[0049] The ingot in step 2) is placed in a heat treatment furnace and heat treated at 1200° C. for 40 minutes; hot forging is performed at an initial forging temperature of 1200° C. and a final forging temperature of 900° C. The size after forging is 18 mm thick, and then a homogenization heat treatment is performed at 900° C. for 0.5 hours to obtain an alloy plate;

[0050] 4) Rolled plate:

[0051] The alloy plate described in step 3) is cold rolled using a dispersion material plate prepared by special equipment and process, with a deformation amount of 7% per pass, until the thickness is 1.2 mm;

[0052] 5) Pipe making:

[0053] The pipe is made by welding and the weld is cut off to obtain a pipe with an outer diameter of Φ15mm and a length of 450mm;

[0054] 6) Precision drawing

[0055] The tube obtained in step 5) is drawn using precision drawing equipment through coordinated control of inner and outer dies, and is drawn using outer dies of Φ14, Φ13, Φ12, Φ11, and Φ10 respectively, and finally drawn using an outer die of Φ10 and an inner die of Φ9 to obtain a tube blank with an outer diameter of Φ10mm, an inner diameter of Φ9mm, and a length of 500mm.

[0056] 7) Head

[0057] The straight tube obtained in step 6) is clamped on a lathe, with the sealing end exposed by 50 mm, and a spinning wheel is used to seal the tube mouth at an angle of 45° inward by a spinning process. The obtained sealing head has good sealing performance, is safe and reliable, and makes the protective tube sleeve have good high temperature resistance and corrosion resistance, thereby improving the service life of the temperature sensor;

[0058] 8) Calendering:

[0059] By using a high-hardness bright wheel and matching it with a precise inner mold, we can obtain a precious metal protective sleeve with uniform inner and outer diameters and wall thickness and bright inner and outer surfaces.

[0060] 9) Finished product inspection: Penetrant testing to check if the pipe has no leakage, the inner and outer surfaces of the pipe are bright, the wall thickness tolerance is less than 0.01mm, and the straightness deviation does not exceed 0.2mm.

[0061] Example 2

[0062] 1) Platinum-rhodium 5 alloy is selected and prepared according to the nominal composition, with a platinum content of 95%, a rhodium content of 5%, and a material purity of ≥99.95%; the preparation is carried out according to the mass percentage of platinum-rhodium 5 alloy 99.5% and a dispersant 0.5%, wherein the dispersant is a mixture of 0.2% zirconium and 0.3% scandium, and the purity is ≥99.95%;

[0063] 2) Vacuum medium frequency melting:

[0064] The ingredients of each substance in step 1) are placed in a smelting furnace, and smelted at a vacuum of 1 to 50 Pa, filled with argon gas for protection, and the smelting temperature is 1860 to 2000° C. After each material is completely melted, magnetic stirring is performed to uniformly keep the temperature for 4 minutes, and then rapid casting is performed to obtain an ingot;

[0065] 3) Hot forging:

[0066] The ingot in step 2) is placed in a heat treatment furnace and heat treated at 1250° C. for 45 minutes; hot forging is performed with an initial forging temperature of 1250° C. and a final forging temperature of 900° C.; and then homogenization heat treatment is performed at 1250° C. for 0.5 hours to obtain an alloy plate;

[0067] 4) Rolled plate:

[0068] The alloy plate of step 3) is rolled to 1.5 mm by using a dispersion material plate prepared by special equipment and process, and the deformation amount of each pass is 5%;

[0069] 5) Pipe making:

[0070] Prepare seamless pipes by spinning to obtain pipe blanks with an outer diameter of Φ20mm and a length of 300mm;

[0071] 6) Precision drawing

[0072] The tube described in step 5) is drawn using precision drawing equipment through coordinated control of inner and outer dies, and is drawn using outer dies of Φ19, Φ18, Φ17, Φ16, and Φ15 respectively, and finally drawn using an outer die of Φ14 and an inner die of Φ13 to obtain a tube blank with an outer diameter of Φ14 mm and an inner diameter of Φ13 mm.

[0073] 7) Head

[0074] The straight tube obtained in step 6) is clamped on a lathe, with the sealing end exposed by 50 mm, and a spinning wheel is used to spin the tube inward at an angle of 45° to seal the tube;

[0075] 8) Calendering:

[0076] By using a high-hardness bright wheel and matching it with a precise inner mold, we can obtain a precious metal protective sleeve with uniform inner and outer diameters and wall thickness and bright inner and outer surfaces.

[0077] 9) Finished product inspection: Penetrant testing to check if the pipe has no leakage, the inner and outer surfaces of the pipe are bright, the wall thickness tolerance is less than 0.01mm, and the straightness deviation does not exceed 0.2mm.

[0078] Example 3

[0079] 1) Select platinum-iridium 10 alloy, mix according to nominal composition, platinum content 90%, iridium content 10%, material purity ≥ 99.95%, and do not add dispersant;

[0080] 2) Vacuum medium frequency melting:

[0081] The ingredients of the above-mentioned substances are placed in a smelting furnace, smelted at a vacuum of 1 to 50 Pa, filled with argon gas for protection, and the smelting temperature is 2050 to 2400° C. After the materials are completely melted, they are magnetically stirred evenly and kept warm for 5 minutes, and then quickly cast to obtain an ingot;

[0082] 3) Hot forging:

[0083] The ingot in step 2) is placed in a heat treatment furnace and heat treated at 1300° C. for 40 minutes; hot forging is performed with an initial forging temperature of 1300° C. and a final forging temperature of 950° C.; and then homogenization heat treatment is performed at 1300° C. for 0.5 hours to obtain an alloy plate;

[0084] 4) Rolled plate:

[0085] The alloy plate described in step 3) is cold rolled, with a deformation amount of 5% per pass, until the alloy plate is rolled to 1.0 mm;

[0086] 5) Pipe making:

[0087] The pipe is made by welding and the weld is cut off, or seamless pipe is made by spinning to obtain a pipe blank with an outer diameter of Φ13mm;

[0088] 6) Precision drawing

[0089] The tube described in step 5) is drawn using precision drawing equipment through coordinated control of inner and outer dies, and is drawn using outer dies of Φ12, Φ11, Φ10, and Φ9 respectively, and finally drawn using an outer die of Φ8 and an inner die of Φ7 to obtain a tube blank with an outer diameter of Φ8mm and an inner diameter of Φ7mm.

[0090] 7) Head

[0091] The straight tube obtained in step 6) is clamped on a lathe, with the sealing end exposed by 50 mm, and a spinning wheel is used to seal the tube mouth at an angle of 45° inward by a spinning process. The obtained head has uniform wall thickness and shape and size, and high assembly accuracy;

[0092] 8) Calendering:

[0093] By using a high-hardness bright wheel and matching it with a precise inner mold, we can obtain a precious metal protective sleeve with uniform inner and outer diameters and wall thickness and bright inner and outer surfaces.

[0094] 9) Finished product inspection: Finished product inspection: Penetrant testing to check if the pipe has no leakage, the inner and outer surfaces of the pipe are bright, the wall thickness tolerance is less than 0.01mm, and the straightness deviation does not exceed 0.2mm.

[0095] Example 4

[0096] 1) Select platinum yellow 5 alloy and mix it according to the nominal composition, with a platinum content of 95%, a gold content of 5%, and a material purity of ≥99.95%;

[0097] 2) Vacuum medium frequency melting:

[0098] The ingredients of the above-mentioned substances are placed in a smelting furnace, smelted at a vacuum of 1 to 50 Pa, filled with argon gas for protection, and the smelting temperature is 1850 to 1950° C. After the materials are completely melted, they are magnetically stirred evenly and kept warm for 5 minutes, and then quickly cast to obtain an ingot;

[0099] 3) Hot forging:

[0100] The ingot in step 2) is placed in a heat treatment furnace and annealed at 1100° C. for 40 minutes; hot forged at an initial forging temperature of 1100° C. and a final forging temperature of 900° C.; and then homogenized at 950° C. for 0.5 hours to obtain an alloy plate;

[0101] 4) Rolled plate:

[0102] The alloy plate described in step 3) is cold-rolled by a dispersion material plate prepared by special equipment and process, with a deformation amount of 6% per pass, until the plate is rolled to 0.8 mm;

[0103] 5) Pipe making:

[0104] The seamless tube was prepared by spinning to obtain a tube blank with an outer diameter of Φ14mm and a length of 300mm;

[0105] 6) Precision drawing

[0106] The tube described in step 5) is drawn using precision drawing equipment through coordinated control of inner and outer dies, and is drawn using outer dies of Φ13, Φ12, Φ11, and Φ10 respectively, and finally drawn using an outer die of Φ9 and an inner die of Φ8 to obtain a tube blank with an outer diameter of Φ9mm and an inner diameter of Φ8mm.

[0107] 7) Head

[0108] The straight tube obtained in step 6) is clamped on a lathe, with the sealing end exposed by 50 mm, and a spinning wheel is used to seal the tube mouth at an angle of 45° inward by a spinning process. The obtained head has uniform wall thickness and shape and size, and high assembly accuracy;

[0109] 8) Calendering:

[0110] By using a high-hardness bright wheel and matching it with a precise inner mold, we can obtain a precious metal protective sleeve with uniform inner and outer diameters and wall thickness and bright inner and outer surfaces.

[0111] 9) Finished product inspection: Finished product inspection: Penetrant testing to check if the pipe has no leakage, the inner and outer surfaces of the pipe are bright, the wall thickness tolerance is less than 0.01mm, and the straightness deviation does not exceed 0.2mm.

[0112] Experimental Example 1

[0113] The service life of the platinum-based alloy protection sleeves obtained in Examples 1-4 of this case and the ordinary protection sleeves purchased on the market were verified by use. The platinum-based alloy protection sleeves obtained in Examples 1-4 of this case and the ordinary protection sleeves purchased on the market were assembled with temperature sensors of the same model and installed in the same special glass kiln for use under high temperature conditions. The operating temperature and frequency of each temperature sensor were observed to be the same. The specific service life is shown in Table 1.

[0114] Table 1 Service life of protective casing

[0115] Serial number category life 1 Ordinary casing 10 months 2 Example 1: Sleeve 18 months 3 Example 2: Sleeve 20 months 4 Example 3: Sleeve 17 months 5 Example 4: Sleeve 15 months

[0116] It can be seen that the service life of the platinum-based alloy protective sleeve is much higher than that of the ordinary protective sleeve, and the service life of the protective sleeve with the addition of dispersant is even longer. The service life of the platinum-based alloy sleeve obtained by cold rolling after homogenization heat treatment of the alloy plate after hot forging and then making a tube has been significantly extended, and has been significantly improved in high-temperature mechanical properties and service life compared with the platinum-based alloy sleeve obtained by heat treatment and cold rolling after drawing. Referring to the comparison of the service life of the sleeves in Example 3 and Example 4, and Example 1 and Example 2, the improvement of the smelting and hot forging conditions has a significant effect on the service life of the material, especially the improvement of the homogenization heat treatment conditions of the alloy plate after hot forging, which has a significant effect on the service life of the material. Similarly, when used under extremely complex working conditions such as high temperature, strong medium, airflow scouring, thermal vibration, etc., the platinum-based alloy protective sleeve can not only ensure the functionality of the sensor, but also greatly improve the service life.

[0117] The serial numbers of the above embodiments of the present invention are only for description and do not represent the advantages or disadvantages of the embodiments.

[0118] The embodiments of the present invention are described above, but the present invention is not limited to the above-mentioned specific implementation modes. The above-mentioned specific implementation modes are merely illustrative and not restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the purpose of the present invention and the claims, which are all within the protection of the present invention.

Claims

1. A method for preparing a platinum-based alloy protective sleeve, characterized in that: The following steps are involved: S1. Preparation of platinum-based alloy plate: melting the raw materials under a vacuum degree of 1-50 Pa, and making the alloy ingot into a platinum-based alloy rolled plate through hot forging and cold rolling deformation process. During hot forging, the ingot is placed in a heat treatment furnace, and hot forged after heat treatment at 1200-1450°C for 30-60 minutes; hot forging into an alloy plate, and then homogenizing heat treatment at 1200-1400°C for 30-60 minutes; during hot forging, the initial forging temperature is 1200-1400°C, and the final forging temperature is 900-1200°C; the hot forged alloy plate is cold rolled for multiple times until the required alloy plate thickness is reached, and the deformation amount of each pass is 5%-15%; the raw materials include platinum-based alloy; S2. Pipe making: bending the rolled plate into a tube shape to make seamless pipes; S3, precision drawing: Through the coordinated control of the inner and outer dies, the seamless tube is drawn to obtain a tube blank. During precision drawing, the thickness deformation of the tube wall is 1-10% each time, and the outer diameter of the tube blank after drawing is 2 / 3 of the original; S4, head sealing: the head sealing is carried out by the spinning process, and the pipe mouth of the tube blank is spun inward at an angle of 45°; S5. Calendering: Use a high-hardness bright wheel with a precision inner mold to calender the tube blank to obtain a platinum-based alloy protective sleeve; The platinum-based alloy is a platinum-rhodium alloy, a platinum-iridium alloy or a platinum-gold alloy. The raw material also includes a dispersant, which is one or more of zirconium, scandium, cerium, yttrium and calcium. The added amount of the dispersant is 0.5% of the alloy mass.

2. The method for preparing a platinum-based alloy protective sleeve according to claim 1, characterized in that: The purity of each material in the platinum-based alloy is greater than 99.95%.

3. The method for preparing a platinum-based alloy protective sleeve according to claim 1, characterized in that: The vacuum melting process is: Under argon protection, various materials are placed in a melting furnace according to the proportion, and are melted at a vacuum degree of 1 to 50 Pa. After the materials are completely melted, they are kept warm and magnetically stirred for 3 to 6 minutes, and then quickly cast to obtain an ingot.

4. A method for preparing a platinum-based alloy protective sleeve as claimed in claim 3, characterized in that: The melting temperature during vacuum melting is 1800~2500℃.

5. A platinum-based alloy protective sleeve made according to the preparation method according to any one of claims 1 to 4.