A kind of stainless steel fiber felt and preparation method thereof

Abstract

The present invention provides a stainless steel fiber felt and a preparation method thereof, belonging to the technical field of nonwoven fabrics. The preparation method comprises the following steps: the stainless steel fiber felt blank is pre-sintered and then loaded into a furnace, and then transferred to a vacuum sintering furnace for sintering. The stainless steel fiber felt prepared by the method of the present invention not only solves the problem of uneven bubbling of the existing stainless steel fiber felt after folding for filtering, but also improves the mechanical properties and air permeability of the stainless steel fiber felt.

Description

Technical Field

[0001] The invention belongs to the technical field of nonwoven fabrics, and in particular relates to a stainless steel fiber felt and a preparation method thereof. Background Art

[0002] High-precision stainless steel fiber felt is a material with excellent performance, widely used in filtration, thermal insulation and protection, especially in the fields of defense industry. The filtration accuracy of stainless steel fiber felt is required to reach 3-5μm. The sintering process in its manufacturing process has a key impact on the quality and performance of the product. However, there are some problems with the existing sintering process, such as low production efficiency and uneven bubbling after pleating. The uneven bubbling of the pleated filter element will lead to:

[0003] (1) Unstable filtration efficiency: Due to the uneven formation of bubbles, the effective utilization of the filtration area is reduced, thus affecting the filtration efficiency;

[0004] (2) Uneven filtering effect: Uneven bubbles will cause uneven filtering effect of the pleated filter element, resulting in unstable impurity content in the filtered liquid;

[0005] (3) Shortened filter element life: Uneven bubbles will accelerate the damage of the pleated filter element and shorten its service life;

[0006] (4) Unstable performance: Uneven bubbles will affect the flow rate and flow of the liquid, resulting in unstable equipment performance. Summary of the invention

[0007] The purpose of the present invention is to solve the difficulties existing in the above-mentioned prior art, to provide a stainless steel fiber felt and a preparation method thereof, and to solve the problem of uneven bubbling during filtration after folding of the existing stainless steel fiber felt.

[0008] The present invention is achieved through the following technical solutions:

[0009] The first aspect of the present invention provides a method for preparing stainless steel fiber felt. The stainless steel fiber felt blank is pre-sintered and then loaded into a furnace, and then transferred to a vacuum sintering furnace for sintering to obtain the stainless steel fiber felt.

[0010] A further improvement of the present invention is:

[0011] The pre-sintering temperature of the stainless steel fiber felt blank is 300-800°C, and the time is 20-60 minutes. After the pre-sintering, the thickness of the stainless steel fiber felt blank reaches 0.4-0.7 times of the original felt blank.

[0012] A further improvement of the present invention is:

[0013] The stainless steel fiber felt blank has a thickness of 1.0 to 2.0 mm and is formed by paving stainless steel fibers with a wire diameter of 6 to 10 μm.

[0014] A further improvement of the present invention is:

[0015] The pre-sintered stainless steel fiber felt blank is loaded into the furnace. The specific steps are as follows:

[0016] Step 1: Place a molybdenum plate interlayer, 1 to 2 stainless steel metal meshes and a molybdenum plate interlayer in order from bottom to top on the bottom layer of the furnace frame;

[0017] The second step is to place a pre-sintered stainless steel fiber felt blank or a stainless steel fiber felt blank covered with mesh on both sides on the molybdenum plate interlayer placed in the first step, and then stack and place the stainless steel fiber felt blank or the stainless steel fiber felt blank covered with mesh on both sides and a molybdenum plate interlayer in the order of one to 30 stainless steel fiber felt blanks, and then place 1 to 2 stainless steel metal meshes and a molybdenum plate interlayer in the order of one to 30 stainless steel fiber felt blanks on the top;

[0018] The third step is to pressurize the assembled stainless steel fiber felt blank.

[0019] A further improvement of the present invention is:

[0020] In the second step, the covering mesh is a stainless steel metal mesh made of stainless steel fiber wire with a wire diameter of 0.06-0.6 mm, and the mesh number of the stainless steel metal mesh is 20-80 meshes.

[0021] A further improvement of the present invention is:

[0022] The covered mesh is tempered and hot rolled before loading into the furnace, specifically:

[0023] The net is tempered in a vacuum sintering furnace at a temperature of 200-500°C, a holding time of 1h-6h, a cooling rate of 10-25°C / min, and a vacuum degree of 3×10 -3 ~3×10 -1 Pa;

[0024] The tempered covered mesh is hot rolled at a temperature of 1000-1100°C.

[0025] A further improvement of the present invention is:

[0026] In the third step, the assembled stainless steel fiber felt blank is pressurized, and the specific operation is as follows:

[0027] Place 1 to 10 perforated molybdenum plates on the top molybdenum plate interlayer for pressurization;

[0028] The perforated molybdenum plate is 1-15 cm larger than the stainless steel fiber felt blank, weighs 5-30 kg, has a thickness of 3-15 mm, a perforated diameter of 12-24 mm, and a hole spacing of 30-100 mm.

[0029] A further improvement of the present invention is:

[0030] The stainless steel fiber felt blank or the stainless steel fiber felt blank covered with mesh on both sides after loading is transferred to the vacuum sintering furnace for sintering. The specific parameters are:

[0031] The sintering temperature is 750~1250℃, the holding time is 1~8h, the heating rate is 1~15℃ / min, and the vacuum degree is 5×10 -3 ~1×10 -1 Pa.

[0032] A second aspect of the present invention provides a stainless steel fiber felt, which is prepared by the method for preparing the stainless steel fiber felt described above.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] The stainless steel fiber felt prepared by the present invention is prepared by pre-sintering the stainless steel fiber felt blank and then loading it into a furnace, and then transferring it to a vacuum sintering furnace for sintering again. The stainless steel fiber felt not only solves the problem of uneven bubbling during filtration after folding of the existing stainless steel fiber felt, but also improves the mechanical properties and air permeability of the stainless steel fiber felt.

[0035] The invention can improve the quality and performance of the product, increase the yield rate and reduce the production cost. In addition, the method of the invention can also realize continuous production and improve production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is a schematic diagram of loading the stainless steel fiber felt blank into the furnace;

[0037] Figure 2 This is a schematic diagram of a punched molybdenum plate;

[0038] Figure 3 Schematic diagram of bubble point test for pleated filter element. DETAILED DESCRIPTION

[0039] The present invention is further described in detail below in conjunction with the accompanying drawings:

[0040] The present invention provides a method for preparing stainless steel fiber felt, which specifically comprises the following steps:

[0041] Step 1: Temper the screen in a vacuum sintering furnace at a temperature of 200-500°C, a holding time of 1h-6h, a cooling rate of 10-25°C / min, and a vacuum degree of 3×10 -3 ~3×10 -1 Pa; the tempered covered mesh is hot rolled, and the rolling temperature needs to be between 1000 and 1100°C.

[0042] The covering mesh is a stainless steel metal mesh made of stainless steel fiber wires with a wire diameter of 0.06 to 0.6 mm, and the mesh number of the stainless steel metal mesh is 20 to 80 meshes.

[0043] Tempering and hot rolling the covered mesh are to improve the mechanical properties of the covered mesh and reduce its internal stress. Among them, the tempering temperature in the present invention is 200-500°C, the holding time is 1-6h, and the cooling rate is 10-25°C / min, in order to improve the mechanical properties of the covered mesh and reduce the internal stress. If it is greater than this range, the metal mesh grain will increase and the hardness will decrease; if it is less than this range, the metal mesh will be too hard, and the strength and toughness will deteriorate. Hot rolling after tempering is to improve the thermal deformation resistance of the covered mesh, improve the flatness of the metal mesh and improve the mechanical properties.

[0044] Step 2: Pretreat the stainless steel fiber felt blank: Pretreat the stainless steel fiber felt blank by a pre-sintering method to form a semi-sintered felt with a thickness of 0.4 to 0.7 times that of the original felt blank. The pre-sintering temperature is 300 to 800° C. and the time is 20 to 60 minutes.

[0045] The stainless steel fiber felt blank has a thickness of 1.0 to 2.0 mm and is made of stainless steel fibers with a wire diameter of 6 to 10 μm.

[0046] Pre-sintering is to reduce the thickness of the stainless steel fiber felt blank to ensure that the bulging and softening caused by the large deformation due to excessive thickness of the felt blank during the sintering process will not be solved. Other methods are not used to reduce the thickness in order to ensure that the overlap of the fibers is not damaged and to ensure the randomness of the fiber felt pore structure as much as possible.

[0047] Step 3: Load the pre-treated high-precision stainless steel fiber felt into the furnace. Figure 1 As shown, the specific steps are as follows:

[0048] Step 1: Place a molybdenum plate interlayer 3, 1 to 2 stainless steel metal meshes 4 and a molybdenum plate interlayer 3 in order from bottom to top on the bottom layer of the furnace frame 1; wherein the thickness of the molybdenum plate interlayer 3 is 0.6 to 1.2 mm, and the size of the molybdenum plate interlayer should be 1 to 25 cm larger than the size of the felt blank; the stainless steel metal mesh 4 is a metal mesh made of stainless steel wire with a wire diameter of 0.03 to 0.1 mm, and the mesh number is 100 to 150 meshes; this step plays a protective role, protecting the impurities volatilized during the sintering process of the stainless steel fiber felt from being adsorbed by the dense mesh;

[0049] In the second step, a pre-sintered stainless steel fiber felt blank 2 or a stainless steel fiber felt blank 2 covered with mesh on both sides is placed on the molybdenum plate interlayer 3 placed in the first step, and the stainless steel fiber felt blank or the stainless steel fiber felt blank 2 covered with mesh on both sides and a molybdenum plate interlayer 3 are stacked and placed in the order of one stainless steel fiber felt blank or one stainless steel fiber felt blank 2 covered with mesh on both sides and one molybdenum plate interlayer 3, the number of stainless steel fiber felt blanks 2 is 1 to 30, and 1 to 2 stainless steel metal meshes 4 and a molybdenum plate interlayer 3 are placed on the top in sequence;

[0050] The third step is to pressurize the installed stainless steel fiber felt blank, specifically:

[0051] 1 to 10 perforated molybdenum plates 5 are placed on the top molybdenum plate interlayer 3 and pressurized; Figure 2 As shown, the perforated molybdenum plate is 1-15 cm larger than the stainless steel fiber felt blank, weighs 5-30 kg, has a thickness of 3-15 mm, a perforated diameter of 12-24 mm, and a hole spacing of 30-100 mm.

[0052] The purpose of pressurizing is to make the fiber felt bear the force as a whole, so that sintering necks can be formed more easily between the fibers and the fiber felt is flat as a whole. Failure to apply pressure will cause defects such as bulging, softening, and fluffing of the fiber felt.

[0053] Step 4: The assembled stainless steel fiber felt blank is transferred to a vacuum sintering furnace for sintering, wherein the sintering temperature is 750-1250°C, the holding time is 1-8h, the heating rate is 1-15°C / min, and the vacuum degree is 5×10 -3 ~1×10 -1 Pa.

[0054] If the sintering process exceeds this range, the sintering neck of the fiber felt will grow abnormally, causing it to become hard and brittle; if it is below this range, the fibers and between the fibers and the covering mesh cannot be completely sintered, resulting in defects such as softening and bulging.

[0055] Example 1

[0056] The method of the present invention is used to prepare stainless steel fiber felt, comprising the following steps:

[0057] Step 1: Temper the screen in a vacuum sintering furnace at a temperature of 500°C, a holding time of 6 hours, a cooling rate of 25°C / min, and a vacuum degree of 8×10 -2 ~3×10 -2 Pa, after tempering, the covered mesh needs to be hot rolled, and the rolling temperature needs to be 1100℃;

[0058] Step 2: Pre-treat the 5μm high-precision stainless steel fiber felt blank: pre-sinter the felt blank by a pre-sintering method to form a semi-sintered felt with a thickness of 0.7 times that of the original felt blank. The pre-sintering temperature is 800°C, the holding time is 60min, the quantity is 20 sheets, and the size is 800×1300mm.

[0059] Step 3: Load the pre-treated 5μm high-precision stainless steel fiber felt into the furnace. The specific steps are as follows:

[0060] Step 1: Place a molybdenum plate interlayer with a thickness of 1.2mm on the furnace frame, and place two stainless steel metal meshes with a mesh number of 150 and a wire diameter of 0.06mm on the molybdenum plate interlayer, and then cover it with another molybdenum plate interlayer;

[0061] Step 2: Place a 5μm high-precision stainless steel fiber felt blank with a mesh on both sides on top of the molybdenum plate interlayer placed in the first step, and stack them in the order of a 5μm high-precision stainless steel fiber felt blank with a mesh on both sides and a molybdenum plate interlayer. The size of the molybdenum plate interlayer is 820×1320mm. After the fiber felt is installed, place two protective stainless steel metal meshes on top and continue to cover a molybdenum plate interlayer. The specification requirements are the same as in the first step;

[0062] Step 3: After the felt blank is installed, 5 perforated molybdenum plates are placed on the top layer for pressure. The perforated molybdenum plates are 815×1315mm in size, 22kg in weight, 5mm in thickness, 20mm in diameter, and 70mm in spacing.

[0063] Step 4: Transfer the assembled high-precision stainless steel fiber felt to the vacuum sintering furnace and set the sintering process to 1250°C, 5h holding time, 15°C / min heating rate, and 3×10 -2 ~8×10 -2 Pa, that’s it.

[0064] The stainless steel fiber felt prepared in Example 1 was inspected on the surface, and it was found that the surface had no softness or fuzzing defects. The performance test results were shown in Table 1, and the filtration accuracy was 4.98 μm and the air permeability was 55 L / dm 2 ·min, tensile strength 249.17N, elongation 14.12%, it can be seen that the mechanical properties and air permeability are higher than the design requirements.

[0065] Table 1 Performance test results of stainless steel fiber felt prepared in Example 1

[0066]

[0067] The stainless steel fiber felt prepared in Example 1 was subjected to a pleated wave filtration test. Figure 3As shown, 6 is air bubble, 7 is filter medium, 8 is pleated filter element. It is found that the bubbling is uniform when pleated and the bubble point meets the use requirements.

[0068] Example 2

[0069] The method of the present invention is used to prepare stainless steel fiber felt, comprising the following steps:

[0070] Step 1: Temper the screen in a vacuum sintering furnace at 200°C for 3 hours, cooling rate of 10°C / min, and vacuum degree of 8×10 -2 ~3×10 -2 Pa, after tempering, the covered mesh needs to be hot rolled, and the rolling temperature needs to be 1000℃;

[0071] Step 2: Pre-treat the 5μm high-precision stainless steel fiber felt blank: pre-sinter the felt blank by a pre-sintering method to form a semi-sintered felt with a thickness of 0.5 times that of the original felt blank. The pre-sintering temperature is 400°C, the holding time is 50min, the quantity is 25 sheets, and the size is 800×1300mm;

[0072] Step 3: Load the pre-treated 5μm high-precision stainless steel fiber felt into the furnace. The specific steps are as follows:

[0073] Step 1: Place a molybdenum plate interlayer with a thickness of 0.6mm on the furnace frame, and place a stainless steel metal mesh with a mesh number of 100 and a wire diameter of 0.06mm on the molybdenum plate interlayer, and then cover it with another molybdenum plate interlayer;

[0074] Step 2: Place a 5μm high-precision stainless steel fiber felt blank with a mesh on both sides on top of the molybdenum plate interlayer placed in the first step, and stack them in the order of a 5μm high-precision stainless steel fiber felt blank with a mesh on both sides and a molybdenum plate interlayer. The size of the molybdenum plate interlayer is 820×1320mm. After the fiber felt is installed, place a stainless steel metal mesh for protection on top, and continue to cover a molybdenum plate interlayer. The specification requirements are the same as in the first step;

[0075] Step 3: After the felt blank is installed, place two perforated molybdenum plates on the top layer for pressure. The perforated molybdenum plates have a size of 815×1315mm, a weight of 30kg, a thickness of 10mm, a perforated diameter of 12mm, and a hole spacing of 100mm.

[0076] Step 4: Transfer the assembled high-precision stainless steel fiber felt to the vacuum sintering furnace and set the sintering process to 750°C, 8h holding time, 1°C / min heating rate, and 3×10 -2 ~8×10 -2 Pa, that’s it.

[0077] The stainless steel fiber felt prepared in Example 2 was inspected on the surface, and it was found that the surface had no softness or fuzzing defects. The performance test results were shown in Table 2, and the filtration accuracy was 4.83 μm and the air permeability was 51 L / dm 2 ·min, tensile strength 212.33N, elongation 15.36%, it can be seen that the mechanical properties and air permeability are higher than the design requirements.

[0078] Table 2 Performance test results of stainless steel fiber felt prepared in Example 2

[0079]

[0080] The stainless steel fiber felt prepared in Example 2 was subjected to a pleated wave filtration test. Figure 3 As shown, it was found that the bubbling was uniform when folding and the bubble point met the use requirements.

[0081] Example 3

[0082] The method of the present invention is used to prepare stainless steel fiber felt, comprising the following steps:

[0083] Step 1: Temper the screen in a vacuum sintering furnace at a temperature of 300°C, a holding time of 1h, a cooling rate of 15°C / min, and a vacuum degree of 8×10 -2 ~3×10 -2 Pa, after tempering, the covered mesh needs to be hot rolled, and the rolling temperature needs to be 1050℃;

[0084] Step 2: Pre-treat the 5μm high-precision stainless steel fiber felt blank: pre-sinter the felt blank by a pre-sintering method to form a semi-sintered felt with a thickness of 0.6 times that of the original felt blank. The pre-sintering temperature is 600°C, the holding time is 40min, the quantity is 30 sheets, and the size is 800×1300mm;

[0085] Step 3: Load the pre-treated 5μm high-precision stainless steel fiber felt into the furnace. The specific steps are as follows:

[0086] Step 1: Place a molybdenum plate interlayer with a thickness of 0.8mm on the furnace frame, and place two stainless steel metal meshes with a mesh number of 110 and a wire diameter of 0.08mm on the molybdenum plate interlayer, and then cover it with another molybdenum plate interlayer;

[0087] Step 2: Place a 5μm high-precision stainless steel fiber felt blank with a mesh on both sides on top of the molybdenum plate interlayer placed in the first step, and stack them in the order of a 5μm high-precision stainless steel fiber felt blank with a mesh on both sides and a molybdenum plate interlayer. The size of the molybdenum plate interlayer is 820×1320mm. After the fiber felt is installed, place two protective stainless steel metal meshes on top and continue to cover a molybdenum plate interlayer. The specification requirements are the same as in the first step;

[0088] Step 3: After the felt blank is installed, 8 perforated molybdenum plates are placed on the top layer for pressure. The perforated molybdenum plates have a size of 815×1315mm, a weight of 10kg, a thickness of 8mm, a perforated diameter of 24mm, and a hole spacing of 30mm.

[0089] Step 4: Transfer the assembled high-precision stainless steel fiber felt to the vacuum sintering furnace and set the sintering process to 900°C, 6h holding time, 8°C / min heating rate, and 3×10 -2 ~8×10 -2 Pa, that’s it.

[0090] The surface of the stainless steel fiber felt prepared in Example 3 was inspected, and it was found that the surface had no softness or fuzzing defects. The performance test results were shown in Table 3, and the filtration accuracy was 4.82 μm and the air permeability was 53 L / dm 2 ·min, tensile strength 226.82N, elongation 14.84%, it can be seen that the mechanical properties and air permeability are higher than the design requirements.

[0091] Table 3 Performance test results of stainless steel fiber felt prepared in Example 3

[0092]

[0093] The stainless steel fiber felt prepared in Example 3 was subjected to a pleated wave filtration test. Figure 3 As shown, it was found that the bubbling was uniform when folding and the bubble point met the use requirements.

[0094] Example 4

[0095] The method of the present invention is used to prepare stainless steel fiber felt, comprising the following steps:

[0096] Step 1: Pre-treat the 5μm high-precision stainless steel fiber felt blank: pre-sinter the felt blank by a pre-sintering method to form a semi-sintered felt with a thickness of 0.4 times that of the original felt blank. The pre-sintering temperature is 500°C, the holding time is 50min, the quantity is 10 sheets, and the size is 800×1300mm;

[0097] Step 2: Load the pre-treated 5μm high-precision stainless steel fiber felt into the furnace. The specific steps are as follows:

[0098] Step 1: Place a molybdenum plate interlayer with a thickness of 0.9mm on the furnace frame, and place two stainless steel metal meshes with a mesh number of 120 and a wire diameter of 0.03mm on the molybdenum plate interlayer, and then cover it with another molybdenum plate interlayer;

[0099] Step 2: Place a 5μm high-precision stainless steel fiber felt blank on top of the molybdenum plate interlayer placed in the first step, and stack them in the order of one stainless steel fiber felt blank and one molybdenum plate interlayer. The size of the molybdenum plate interlayer is 820×1320mm. After the fiber felt is installed, place two protective stainless steel metal meshes on top and continue to cover a molybdenum plate interlayer. The specification requirements are the same as in the first step.

[0100] Step 3: After the felt blank is installed, place 3 perforated molybdenum plates on the top layer for pressure. The perforated molybdenum plates have a size of 815×1315mm, a weight of 22kg, a thickness of 5mm, a perforated diameter of 20mm, and a hole spacing of 70mm.

[0101] Step 3: Transfer the assembled high-precision stainless steel fiber felt to the vacuum sintering furnace and set the sintering process to 1000°C, 4h holding time, 10°C / min heating rate, and 3×10 -2 ~8×10 -2 Pa, that’s it.

[0102] The surface of the stainless steel fiber felt prepared in Example 4 was inspected, and it was found that the surface had no softness or fuzzing defects. The performance test results were shown in Table 4, and the filtration accuracy was 4.86 μm and the air permeability was 58 L / dm 2 ·min, tensile strength 180.23N, elongation 11.23%, it can be seen that the mechanical properties and air permeability are higher than the design requirements.

[0103] Table 4 Performance test results of stainless steel fiber felt prepared in Example 4

[0104]

[0105] The stainless steel fiber felt prepared in Example 4 was subjected to a pleated wave filtration test. Figure 3 As shown, it was found that the bubbling was uniform when folding and the bubble point met the use requirements.

[0106] Example 5

[0107] The method of the present invention is used to prepare stainless steel fiber felt, comprising the following steps:

[0108] Step 1: Pre-treat the 5μm high-precision stainless steel fiber felt blank: pre-sinter the felt blank by a pre-sintering method to form a semi-sintered felt with a thickness of 0.7 times that of the original felt blank. The pre-sintering temperature is 300°C, the holding time is 50min, the quantity is 20 sheets, and the size is 800×1300mm;

[0109] Step 2: Load the pre-treated 5μm high-precision stainless steel fiber felt into the furnace. The specific steps are as follows:

[0110] Step 1: Place a molybdenum plate interlayer with a thickness of 0.7mm on the furnace frame, and place a stainless steel metal mesh with a mesh number of 130 and a wire diameter of 0.05mm on the molybdenum plate interlayer, and then cover it with another molybdenum plate interlayer;

[0111] Step 2: Place a 5μm high-precision stainless steel fiber felt blank on top of the molybdenum plate interlayer placed in the first step, and stack them in the order of one stainless steel fiber felt blank and one molybdenum plate interlayer. The size of the molybdenum plate interlayer is 820×1320mm. After the fiber felt is installed, place two protective stainless steel metal meshes on top and continue to cover a molybdenum plate interlayer. The specification requirements are the same as in the first step.

[0112] Step 3: After the felt blank is installed, 10 perforated molybdenum plates are placed on the top layer for pressure. The perforated molybdenum plates have a size of 815×1315mm, a weight of 5kg, a thickness of 15mm, a perforated diameter of 18mm, and a hole spacing of 50mm.

[0113] Step 3: Transfer the assembled high-precision stainless steel fiber felt to the vacuum sintering furnace and set the sintering process to 1100°C, 3h holding time, 5°C / min heating rate, and 3×10 -2 ~8×10 -2 Pa, that’s it.

[0114] The surface of the stainless steel fiber felt prepared in Example 5 was inspected, and it was found that the surface had no softness or fuzzing defects. The performance test results were shown in Table 5, and the filtration accuracy was 4.91 μm and the air permeability was 56 L / dm 2 ·min, tensile strength 181.36N, elongation 10.28%, it can be seen that the mechanical properties and air permeability are higher than the design requirements.

[0115] Table 5 Performance test results of stainless steel fiber felt prepared in Example 5

[0116]

[0117] The stainless steel fiber felt prepared in Example 5 was subjected to a pleated wave filtration test. Figure 3 As shown, it was found that the bubbling was uniform when folding and the bubble point met the use requirements.

[0118] Example 6

[0119] The method of the present invention is used to prepare stainless steel fiber felt, comprising the following steps:

[0120] Step 1: Pre-treat the 5μm high-precision stainless steel fiber felt blank: pre-sinter the felt blank by a pre-sintering method to form a semi-sintered felt with a thickness of 0.6 times that of the original felt blank. The pre-sintering temperature is 700°C, the holding time is 20min, the quantity is 25 sheets, and the size is 800×1300mm;

[0121] Step 2: Load the pre-treated 5μm high-precision stainless steel fiber felt into the furnace. The specific steps are as follows:

[0122] Step 1: Place a molybdenum plate interlayer with a thickness of 0.8mm on the furnace frame, and place a stainless steel metal mesh with a mesh number of 140 and a wire diameter of 0.07mm on the molybdenum plate interlayer, and then cover it with another molybdenum plate interlayer;

[0123] Step 2: Place a 5μm high-precision stainless steel fiber felt blank on top of the molybdenum plate interlayer placed in the first step, and stack them in the order of one stainless steel fiber felt blank and one molybdenum plate interlayer. The size of the molybdenum plate interlayer is 820×1320mm. After the fiber felt is installed, place a stainless steel metal mesh for protection on top, and then cover it with a molybdenum plate interlayer. The specification requirements are the same as in the first step.

[0124] Step 3: After the felt blank is installed, 7 perforated molybdenum plates are placed on the top layer for pressure. The perforated molybdenum plates are 815×1315mm in size, 12kg in weight, 3mm in thickness, 15mm in diameter, and 80mm in spacing.

[0125] Step 3: Transfer the assembled high-precision stainless steel fiber felt to the vacuum sintering furnace and set the sintering process to 1200°C, 1h holding time, 12°C / min heating rate, and 3×10 -2 ~8×10 -2 Pa, that’s it.

[0126] The surface of the stainless steel fiber felt prepared in Example 6 was inspected, and it was found that the surface had no softness or fuzzing defects. The performance test results were shown in Table 6, and the filtration accuracy was 4.99 μm and the air permeability was 52 L / dm 2 ·min, tensile strength 185.65N, elongation 12.43%, it can be seen that the mechanical properties and air permeability are higher than the design requirements.

[0127] Table 6 Performance test results of stainless steel fiber felt prepared in Example 6

[0128]

[0129] The stainless steel fiber felt prepared in Example 6 was subjected to a pleated wave filtration test. Figure 3 As shown, it was found that the bubbling was uniform when folding and the bubble point met the use requirements.

[0130] The above technical solution is only one implementation mode of the present invention. For those skilled in the art, it is easy to make various types of improvements or modifications based on the principles disclosed in the present invention, and it is not limited to the technical solution described in the above specific embodiments of the present invention. Therefore, the above description is only preferred and does not have a restrictive meaning.

Claims

1. A method for preparing stainless steel fiber felt, characterized in that: The stainless steel fiber felt blank is pre-sintered and then loaded into a furnace, and then transferred to a vacuum sintering furnace for sintering to obtain; The stainless steel fiber felt blank has a thickness of 1.0 to 2.0 mm and is made of stainless steel fibers with a wire diameter of 6 to 10 μm. The pre-sintered stainless steel fiber felt blank is loaded into the furnace. The specific steps are as follows: Step 1: Place a molybdenum plate interlayer, 1 to 2 stainless steel metal meshes and a molybdenum plate interlayer on the bottom layer of the furnace rack from bottom to top; The second step is to place a pre-sintered stainless steel fiber felt blank or a stainless steel fiber felt blank covered with mesh on both sides on the molybdenum plate interlayer placed in the first step, and then stack and place the stainless steel fiber felt blank or the stainless steel fiber felt blank covered with mesh on both sides and a molybdenum plate interlayer in the order of one to 30 stainless steel fiber felt blanks, and then place 1 to 2 stainless steel metal meshes and a molybdenum plate interlayer in the order of one to 30 stainless steel fiber felt blanks on the top; The third step is to pressurize the assembled stainless steel fiber felt blank.

2. The method for preparing the stainless steel fiber felt according to claim 1, characterized in that: The pre-sintering temperature of the stainless steel fiber felt blank is 300-800°C, and the time is 20-60 minutes. After the pre-sintering, the thickness of the stainless steel fiber felt blank reaches 0.4-0.7 times of the original felt blank.

3. The method for preparing the stainless steel fiber felt according to claim 1, characterized in that: In the second step, the covering mesh is a stainless steel metal mesh made of stainless steel fiber wire with a wire diameter of 0.06-0.6 mm, and the mesh number of the stainless steel metal mesh is 20-80 meshes.

4. The method for preparing the stainless steel fiber felt according to claim 1, characterized in that: The covered mesh is tempered and hot rolled before loading into the furnace, specifically: The net is tempered in a vacuum sintering furnace at a temperature of 200-500°C, a holding time of 1h-6h, a cooling rate of 10-25°C / min, and a vacuum degree of 3×10 -3 ~3×10 -1 Pa; The tempered covered mesh is hot rolled at a temperature of 1000-1100°C.

5. The method for preparing the stainless steel fiber felt according to claim 1, characterized in that: In the third step, the assembled stainless steel fiber felt blank is pressurized, and the specific operation is as follows: Place 1 to 10 perforated molybdenum plates on the top molybdenum plate interlayer for pressurization; The perforated molybdenum plate is 1-15 cm larger than the stainless steel fiber felt blank, weighs 5-30 kg, has a thickness of 3-15 mm, a perforated diameter of 12-24 mm, and a hole spacing of 30-100 mm.

6. The method for preparing stainless steel fiber felt according to claim 1, characterized in that: The stainless steel fiber felt blank or the stainless steel fiber felt blank covered with mesh on both sides after loading is transferred to the vacuum sintering furnace for sintering. The specific parameters are: The sintering temperature is 750-1250℃, the holding time is 1-8h, the heating rate is 1-15℃ / min, and the vacuum degree is 5×10 -3 ~1×10 -1 Pa.

7. A stainless steel fiber felt, characterized in that: The stainless steel fiber felt is prepared by the method for preparing the stainless steel fiber felt according to any one of claims 1 to 6.

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