Disclosure of Invention
One of the technical problems to be solved by the invention is to provide a sintering material box for improving the consistency of the magnetic performance of the rare earth permanent magnet material, wherein the sintering material box has the advantages of improving the consistency of the residual magnetism and the intrinsic coercivity of the rare earth permanent magnet material while taking the tightness and the exhaust function into consideration, along with low manufacturing cost, simple operation steps, reduction of the production operation difficulty, no influence on the production efficiency of the sintered neodymium-iron-boron magnet, no need of using liquid sealing and no introduction of other impurities.
The technical scheme adopted by the invention for solving one of the technical problems is as follows: the utility model provides an improve sintering magazine of tombarthite permanent magnet material magnetism performance uniformity, includes upper end open-ended rectangle box body, rectangle box body pass through preceding curb plate, posterior lateral plate, left side board, right side board and bottom plate and arrange and connect gradually the constitution according to the position under the front and back, posterior lateral plate left side board right side board and the bottom plate between enclose into the rectangle material chamber, the upper end middle part of preceding curb plate be provided with the first recess of undercut, the upper end middle part of posterior lateral plate be provided with the second recess of undercut, the upper end middle part of left side board be provided with the third recess of undercut, the upper end middle part of right side board be provided with the fourth recess of undercut.
The cross sections of the first groove, the second groove, the third groove and the fourth groove along the vertical direction are isosceles trapezoids, and the lower bottoms of the isosceles trapezoids are positioned above the upper bottoms of the first groove, the second groove, the third groove and the fourth groove. In this structure, when a plurality of sintering magazine of range upon range of, because sintering magazine is loaded with the weight after the product is heavier, the sintering magazine of upper strata can generally be shelved earlier at next layer sintering magazine top and forward promotion again, makes upper layer sintering magazine and next layer sintering magazine align the range upon range of from top to bottom, and first recess, second recess, third recess and fourth recess are isosceles trapezoid along the cross-section of vertical direction, can avoid the last layer sintering magazine to appear blocking in the promotion in-process, and the operation is more quick and handy.
The height of the cross sections of the first groove, the second groove, the third groove and the fourth groove along the vertical direction is not more than 5mm, the difference between the bottoms and the bottoms of the cross sections of the first groove, the second groove, the third groove and the fourth groove along the vertical direction is not more than 50mm, the area of the cross section of the first groove is 1% -3% of the area of the front side surface of the rectangular material cavity, the area of the cross section of the second groove is 1% -3% of the area of the rear side surface of the rectangular material cavity, the area of the cross section of the third groove is 1% -3% of the area of the left side surface of the rectangular material cavity, and the area of the cross section of the fourth groove is 1% -3% of the area of the right side surface of the rectangular material cavity.
The bottom of bottom plate be provided with first annular groove, first annular groove's degree of depth be less than first recess second recess third recess and fourth recess's degree of depth, when a plurality of sintering magazine stacks from top to bottom, the top embedding that is located anterior board, posterior lateral plate, left side board and the right side board of the sintering magazine of next floor is located in the first annular groove that the bottom of the sintering magazine of upper strata set up.
The sintering material box for improving the consistency of the magnetic properties of the rare earth permanent magnetic materials further comprises a cover plate, a second annular groove is formed in the bottom of the cover plate, the depth of the second annular groove is smaller than that of the first groove, the second groove, the third groove and the fourth groove, and when the cover plate is arranged above the front side plate, the rear side plate, the left side plate and the right side plate, the front side plate, the rear side plate, the left side plate and the top of the right side plate can be embedded into the second annular groove.
The length of the front side plate along the left-right direction is 250-500mm, the height of the rear side plate along the up-down direction is 30-80mm, the thickness of the rear side plate along the front-back direction is 5-12mm, the length of the rear side plate along the left-right direction is equal to the length of the front side plate along the left-right direction, the height of the rear side plate along the up-down direction is equal to the height of the front side plate along the up-down direction, and the thickness of the rear side plate along the front-back direction is equal to the thickness of the front side plate along the front-back direction; the length of the left side plate along the front-back direction is 250-500mm, the height of the left side plate along the up-down direction is 30-80mm, the thickness of the right side plate along the left-right direction is 5-12mm, the length of the right side plate along the front-back direction is equal to the length of the left side plate along the front-back direction, the height of the right side plate along the up-down direction is equal to the height of the left side plate along the up-down direction, and the thickness of the right side plate along the left-right direction is equal to the thickness of the left side plate along the left-right direction.
The front side plate, the rear side plate, the left side plate, the right side plate and the bottom plate are made of graphite or carbon fiber.
Compared with the prior art, the sintering material box has the advantages that the middle part of the upper end of the front side plate of the sintering material box is provided with the first concave groove which is concave downwards, the middle part of the upper end of the rear side plate is provided with the second concave groove which is concave downwards, the middle part of the upper end of the left side plate is provided with the third concave groove which is concave downwards, the middle part of the upper end of the right side plate is provided with the fourth concave groove which is concave downwards, so that the exhaust channel of blanks during sintering is effectively increased, impurity gas is exhausted from the first concave groove, the second concave groove, the third concave groove and the fourth concave groove in the stage of massive air release of the blanks, the exhaust efficiency and the uniformity of blank exhaust at different positions are improved, the carbon content of the blanks is reduced, the consistency of the carbon content of the blanks is also improved, the consistency of the residual magnetic intrinsic coercive force of rare earth permanent magnet materials of neodymium-iron-boron materials is improved, meanwhile, the bottom plate of the sintering material box is provided with the first annular groove, the cover plate of the sintering material box is provided with a second annular groove, the depths of the first annular groove and the second annular groove are smaller than the depths of the first groove, the second groove, the third groove and the fourth groove, when a plurality of sintering material boxes are stacked up and down and the cover plate is covered on the uppermost sintering material box, the tops of the front side plate, the rear side plate, the left side plate and the right side plate of the uppermost sintering material box are embedded into the second annular groove on the cover plate, and the tops of the front side plate, the rear side plate, the left side plate and the right side plate of the next sintering material box are embedded into the first annular groove arranged at the bottom plate of the sintering material box on the upper layer in other layers of sintering material boxes, so that the blank and air can be prevented from being directly contacted in a large area in the process of entering the sintering furnace, the sealing performance is considered, therefore, the sintering material box of the invention has both the sealing performance and the exhaust function, the consistency of the remanence and intrinsic coercivity of the rare earth permanent magnet material is improved, the manufacturing cost is low, the operation steps are simple, the production operation difficulty is reduced, the production efficiency of the sintered neodymium-iron-boron magnet is not affected, liquid sealing is not needed, and other impurities are not introduced. The second technical problem to be solved by the invention is to provide a method for improving the consistency of the magnetic properties of rare earth permanent magnetic materials. According to the method, the sintering process is adjusted, so that the degassing temperature of the degassing agent is changed from the original fixed temperature to the fluctuation temperature, the degassing process of the neodymium-iron-boron blank is increased, the degassing effect is further improved, impurities are effectively removed, the consistency of the residual magnetism and the intrinsic coercivity of the rare earth permanent magnet material is further improved, meanwhile, the sintering material box is improved, the tightness and the degassing function are both considered, the consistency of the residual magnetism and the intrinsic coercivity of the rare earth permanent magnet material is improved, meanwhile, the manufacturing cost is low, the operation steps are simple, the production operation difficulty is reduced, the production efficiency of the sintered neodymium-iron-boron magnet is not affected, and the impurities are not introduced.
The second technical scheme adopted for solving the technical problems is as follows: a method for improving consistency of magnetic properties of rare earth permanent magnet materials comprises the following steps:
(1) Preparing a material according to a formula of the rare earth permanent magnet material, and obtaining a cast sheet through a rapid hardening and sheet throwing technology;
(2) Hydrogen crushing the cast sheet to obtain alloy coarse powder, and then filling the alloy coarse powder into a tank body protected by inert gas for preservation;
(3) Transferring the alloy coarse powder into an air flow grinding device for grinding to obtain fine powder with the granularity D50 of 4.0-4.5 mu m, and then filling the fine powder into a tank body protected by inert gas, wherein oxygen supplementing is carried out according to the process requirements during the grinding process of the air flow grinding device, and the online oxygen content of the air flow grinding device is kept between 0 and 50 ppm;
(4) Transferring the fine powder to a forming workshop, performing compression forming on the fine powder through a press to obtain a blank, packaging the blank with a vacuum packaging bag, and packaging with a vacuum packaging machine, wherein inert gas is always filled into the press in the compression forming process, and the oxygen content is always lower than 0.02%;
(5) The packaged blank is sent into a sintering film stripping glove box after being subjected to water isostatic pressing treatment, and the oxygen content in the sintering film stripping glove box is reduced to below 0.02 percent;
(6) In a sintering film stripping glove box, film stripping treatment is carried out on blanks, the blanks are taken out from a vacuum packaging bag and then are arranged in a sintering material box which is placed in the sintering film stripping glove box in advance, the sintering material box comprises a rectangular box body with an opening at the upper end, the rectangular box body is formed by splicing a front side plate, a rear side plate, a left side plate, a right side plate and a bottom plate according to the directions of front, rear, left and right sides, rectangular material cavities for arranging the blanks are formed between the front side plate, the rear side plate, the right side plate and the bottom plate in a surrounding manner, a first concave groove which is downwards concave is formed in the middle of the upper end of the front side plate, a second concave groove which is downwards concave is formed in the middle of the upper end of the rear side plate, a third concave groove which is downwards concave is formed in the middle of the upper end of the left side plate, and a fourth concave groove which is downwards concave is formed in the middle of the upper end of the right side plate;
(7) Under the protection of nitrogen, stacking the sintering material boxes filled with blanks up and down according to the furnace loading amount, covering a cover plate on the uppermost sintering material box, and then orderly arranging the stacked sintering material boxes in a furnace chamber of a sintering furnace for high-temperature sintering in a furnace back feeding mode, wherein the high-temperature sintering process adopts a vibration sintering process, and the specific process is as follows: heating for 20min-50min to 330-430 ℃, then repeating the cooling and heating process for 2-5 times, then continuously heating for 60min-120min to 540-650 ℃ and preserving heat for 1h-3h, then heating for 60min-120min to 780-900 ℃ and preserving heat for 1h-3h, continuously heating for 20min-50min to 900-980 ℃ and preserving heat for 1h-3h, then continuously heating for 30min-60min to 1000-1100 ℃ and preserving heat for 3h-8h, finally performing subsequent aging treatment, and discharging after the aging treatment is finished to obtain a sintered neodymium iron boron magnet, namely a rare earth permanent magnet material, wherein the cooling and heating process each time is as follows: firstly cooling for 20min-50min, wherein the cooling amplitude is 40-80 ℃, and then heating for 20min-50min to 330-430 ℃.
The cross sections of the first groove, the second groove, the third groove and the fourth groove along the vertical direction are isosceles trapezoids, and the lower bottoms of the isosceles trapezoids are positioned above the upper bottoms of the first groove, the second groove, the third groove and the fourth groove. The height of the cross sections of the first groove, the second groove, the third groove and the fourth groove along the vertical direction is not more than 5mm, the difference between the bottoms and the bottoms of the cross sections of the first groove, the second groove, the third groove and the fourth groove along the vertical direction is not more than 50mm, the area of the cross section of the first groove is 1% -3% of the area of the front side surface of the rectangular material cavity, the area of the cross section of the second groove is 1% -3% of the area of the rear side surface of the rectangular material cavity, the area of the cross section of the third groove is 1% -3% of the area of the left side surface of the rectangular material cavity, and the area of the cross section of the fourth groove is 1% -3% of the area of the right side surface of the rectangular material cavity.
Compared with the prior patent, the method has the advantages that the middle part of the upper end of the front side plate of the sintering material box is provided with the first concave groove which is downwards concave, the middle part of the upper end of the rear side plate is provided with the second concave groove which is downwards concave, the middle part of the upper end of the left side plate is provided with the third concave groove which is downwards concave, the middle part of the upper end of the right side plate is provided with the fourth concave groove which is downwards concave, thus effectively increasing the exhaust passage of blanks during sintering, and in the stage of discharging a large amount of blanks, impurity gas is discharged from the first concave groove, the second concave groove, the third concave groove and the fourth concave groove, improving the exhaust efficiency and the uniformity of blank exhaust at different positions, reducing the carbon content of the blanks and improving the consistency of the carbon content of the blanks, therefore, the consistency of residual magnetic intrinsic coercive force of the rare earth permanent magnetic material of the neodymium iron boron material is improved, meanwhile, a first annular groove is arranged at the bottom of the bottom plate of the sintering material box, a second annular groove is arranged at the cover plate of the sintering material box, the depths of the first annular groove and the second annular groove are smaller than those of the first groove, the second groove, the third groove and the fourth groove, when a plurality of sintering material boxes are stacked up and down and the cover plate is covered on the uppermost sintering material box, the tops of the front side plate, the rear side plate, the left side plate and the right side plate of the uppermost sintering material box are embedded into the second annular groove on the cover plate, and in other layers of sintering material boxes, the front side plate, the third groove and the fourth groove of the sintering material box on the next layer are embedded into the second annular groove, The tops of the rear side plate, the left side plate and the right side plate are embedded into a first annular groove arranged at the bottom of the bottom plate of the sintering material box at the upper layer, so that blanks can be prevented from being in direct contact with air in a large area in the process of entering a sintering furnace, tightness is considered, the stacked sintering material boxes are fed into the furnace after the sintering (the mode of feeding the furnace after the furnace refers to that a film stripping glove box is connected with a sintering furnace back door, the sintering furnace back door is opened, the stacked sintering material boxes in the film stripping glove box are transferred into the sintering furnace under the nitrogen protection atmosphere), and the stacked sintering material boxes are orderly arranged in the furnace chamber of the sintering furnace to be sintered at high temperature, so that the blanks are prevented from contacting with the air, and the blanks are prevented from being oxidized; In addition, the sintered NdFeB magnet is added with an antioxidant, a lubricant and other additives which ensure that powder is not oxidized and help the powder to be ground by air flow grinding, the additives such as the lubricant, a release agent and the like are also used for improving the powder formability in the stirring and forming stages, the orientation degree of powder particles in a magnetic field is improved, the types of the existing additives are various, the use of the powder modification additive can improve the performance of the sintered NdFeB magnet, so the addition amount of the powder modification additive in the industry is gradually increased, but the additives are a multi-component organic compound, a large amount of C element and O element are introduced, the performance of the NdFeB permanent magnet material is affected if the excessive C element and O element are not discharged in time, Therefore, the invention further improves the sintering process into a vibration sintering process, and specifically: heating for 20min-50min to 330-430 ℃, then repeating the cooling and heating process for 2-5 times, then continuously heating for 60min-120min to 540-650 ℃ and preserving heat for 1h-3h, then continuously heating for 60min-120min to 780-900 ℃ and preserving heat for 1h-3h, continuously heating for 20min-50min to 900-980 ℃ and preserving heat for 1h-3h, then continuously heating for 30min-60min to 1000-1100 ℃ and preserving heat for 3h-8h, Finally, carrying out subsequent aging treatment, and discharging after the aging treatment is finished to obtain a sintered neodymium-iron-boron magnet, namely a rare earth permanent magnet material, wherein the temperature reducing and then increasing process each time is as follows: firstly cooling for 20min-50min, wherein the cooling amplitude is 40-80 ℃, then heating for 20min-50min to 330-430 ℃, discharging C and O (wherein the temperature stage of 330-430 ℃ is the optimal temperature interval for discharging C and O) through the alternation of heating and cooling in the vibration sintering process, thereby changing the degassing temperature of the degassing agent from the original fixed temperature to the fluctuation temperature through adjusting the sintering process, increasing the degassing process of the neodymium iron boron green body, The method further improves the stripping effect, effectively eliminates impurities, improves the consistency of residual magnetism and intrinsic coercivity of the rare earth permanent magnet material, combines the improved sintering material box, ensures that the sealing performance and the exhaust function are both considered, improves the consistency of residual magnetism and intrinsic coercivity of the rare earth permanent magnet material, and has the advantages of low manufacturing cost, simple operation steps, reduced production and operation difficulty, no influence on the production efficiency of the sintered neodymium-iron-boron magnet and no impurity introduction.
Detailed Description
The invention discloses a sintering material box for improving consistency of magnetic properties of rare earth permanent magnet materials, and the sintering material box is further described in detail below with reference to the embodiment of the drawings.
Embodiment one: as shown in fig. 1 to 5, a sintering magazine for improving the consistency of magnetic properties of rare earth permanent magnet materials comprises a rectangular box body with an opening at the upper end, wherein the rectangular box body is formed by arranging and sequentially connecting a front side plate 1, a rear side plate 2, a left side plate 3, a right side plate 4 and a bottom plate 5 according to the front-back left-right lower directions, a rectangular material cavity 6 is formed by encircling between the front side plate 1, the rear side plate 2, the left side plate 3, the right side plate 4 and the bottom plate 5, a first concave groove 7 which is concave downwards is arranged in the middle of the upper end of the front side plate 1, a second concave groove 8 which is concave downwards is arranged in the middle of the upper end of the rear side plate 2, a third concave groove 9 which is concave downwards is arranged in the middle of the upper end of the left side plate 3, and a fourth concave downwards is arranged in the middle of the upper end of the right side plate 4.
In this embodiment, the front side plate 1, the rear side plate 2, the left side plate 3, the right side plate 4 and the bottom plate 5 are made of graphite.
Embodiment two: this embodiment is substantially the same as embodiment one, except that: in this embodiment, the cross sections of the first groove 7, the second groove 8, the third groove 9 and the fourth groove 10 along the vertical direction are isosceles trapezoids, and the lower bottoms of the isosceles trapezoids are located above the upper bottoms thereof.
In this embodiment, the heights of the cross sections of the first groove 7, the second groove 8, the third groove 9 and the fourth groove 10 along the vertical direction are 3mm, the difference between the bottoms and the bottoms of the cross sections of the first groove 7, the second groove 8, the third groove 9 and the fourth groove 10 along the vertical direction is 50mm, the area of the cross section of the first groove 7 is 1% of the front side surface area of the rectangular material cavity 6, the area of the cross section of the second groove 8 is 1% of the rear side surface area of the rectangular material cavity 6, the area of the cross section of the third groove 9 is 1% of the left side surface area of the rectangular material cavity 6, and the area of the cross section of the fourth groove 10 is 1% of the right side surface area of the rectangular material cavity 6.
In this embodiment, the bottom of the bottom plate 5 is provided with a first annular groove 11, the depth of the first annular groove 11 is smaller than the depths of the first groove 7, the second groove 8, the third groove 9 and the fourth groove 10, and when a plurality of sintering cartridges are stacked up and down, the top of the front side plate 1, the rear side plate 2, the left side plate 3 and the right side plate 4 of the sintering cartridge located in the next layer is embedded into the first annular groove 11 provided at the bottom of the sintering cartridge located in the previous layer.
In this embodiment, a sintering magazine for improving consistency of magnetic properties of rare earth permanent magnetic materials further includes a cover plate 12, a second annular groove 13 is provided at the bottom of the cover plate 12, the depth of the second annular groove 13 is smaller than the depth of the first groove 7, the second groove 8, the third groove 9 and the fourth groove 10, and when the cover plate 12 is disposed above the front side plate 1, the rear side plate 2, the left side plate 3 and the right side plate 4, the top of the front side plate 1, the rear side plate 2, the left side plate 3 and the right side plate 4 can be embedded into the second annular groove 13, and the cover plate 12 is made of graphite.
In the present embodiment, the length of the front side plate 1 in the left-right direction is 500mm, the height in the up-down direction is 80mm, the thickness in the front-back direction is 5mm, the length of the rear side plate 2 in the left-right direction is equal to the length of the front side plate 1 in the left-right direction, the height of the rear side plate 2 in the up-down direction is equal to the height of the front side plate 1 in the up-down direction, and the thickness of the rear side plate 2 in the front-back direction is equal to the thickness of the front side plate 1 in the front-back direction; the length of the left side plate 3 in the front-rear direction is 300mm, the height in the up-down direction is 80mm, the thickness in the left-right direction is 5mm, the length of the right side plate 4 in the front-rear direction is equal to the length of the left side plate 3 in the front-rear direction, the height of the right side plate 4 in the up-down direction is equal to the height of the left side plate 3 in the up-down direction, and the thickness of the right side plate 4 in the left-right direction is equal to the thickness of the left side plate 3 in the left-right direction.
Embodiment III: this embodiment is substantially the same as embodiment one, except that: in this embodiment, the cross sections of the first groove 7, the second groove 8, the third groove 9 and the fourth groove 10 along the vertical direction are isosceles trapezoids, and the lower bottoms of the isosceles trapezoids are located above the upper bottoms thereof.
In this embodiment, the height of the cross sections of the first groove 7, the second groove 8, the third groove 9 and the fourth groove 10 in the vertical direction is 5mm, the difference between the bottom and the upper bottom of the cross sections of the first groove 7, the second groove 8, the third groove 9 and the fourth groove 10 in the vertical direction is 50mm, the area of the cross section of the first groove 7 is 3% of the front side area of the rectangular material cavity 6, the area of the cross section of the second groove 8 is 3% of the rear side area of the rectangular material cavity 6, the area of the cross section of the third groove 9 is 3% of the left side area of the rectangular material cavity 6, and the area of the cross section of the fourth groove 10 is 3% of the right side area of the rectangular material cavity 6.
In this embodiment, the bottom of the bottom plate 5 is provided with a first annular groove 11, the depth of the first annular groove 11 is smaller than the depths of the first groove 7, the second groove 8, the third groove 9 and the fourth groove 10, and when a plurality of sintering cartridges are stacked up and down, the top of the front side plate 1, the rear side plate 2, the left side plate 3 and the right side plate 4 of the sintering cartridge located in the next layer is embedded into the first annular groove 11 provided at the bottom of the sintering cartridge located in the previous layer.
In this embodiment, a sintering magazine for improving consistency of magnetic properties of rare earth permanent magnetic materials further includes a cover plate 12, a second annular groove 13 is provided at the bottom of the cover plate 12, the depth of the second annular groove 13 is smaller than the depth of the first groove 7, the second groove 8, the third groove 9 and the fourth groove 10, and when the cover plate 12 is disposed above the front side plate 1, the rear side plate 2, the left side plate 3 and the right side plate 4, the top of the front side plate 1, the rear side plate 2, the left side plate 3 and the right side plate 4 can be embedded into the second annular groove 13, and the cover plate 12 is made of graphite.
In the present embodiment, the length of the front side plate 1 in the left-right direction is 500mm, the height in the up-down direction is 80mm, the thickness in the front-back direction is 5mm, the length of the rear side plate 2 in the left-right direction is equal to the length of the front side plate 1 in the left-right direction, the height of the rear side plate 2 in the up-down direction is equal to the height of the front side plate 1 in the up-down direction, and the thickness of the rear side plate 2 in the front-back direction is equal to the thickness of the front side plate 1 in the front-back direction; the length of the left side plate 3 in the front-rear direction is 300mm, the height in the up-down direction is 80mm, the thickness in the left-right direction is 5mm, the length of the right side plate 4 in the front-rear direction is equal to the length of the left side plate 3 in the front-rear direction, the height of the right side plate 4 in the up-down direction is equal to the height of the left side plate 3 in the up-down direction, and the thickness of the right side plate 4 in the left-right direction is equal to the thickness of the left side plate 3 in the left-right direction.
The invention also discloses a method for improving the consistency of the magnetic properties of the rare earth permanent magnet material, and the method is further described in detail below with reference to the embodiment of the drawings.
Embodiment four: a method for improving consistency of magnetic properties of rare earth permanent magnet materials comprises the following steps:
(1) Preparing materials according to the formula of a 42SH brand neodymium-iron-boron magnet, and obtaining cast sheets through a rapid hardening and sheet throwing technology;
(2) Hydrogen crushing the cast sheet to obtain alloy coarse powder, and then filling the alloy coarse powder into a tank body protected by inert gas for preservation;
(3) Transferring the alloy coarse powder into an air flow grinding device for grinding to obtain fine powder with the granularity D50 of 4.0-4.5 mu m, and then filling the fine powder into a tank body protected by inert gas, wherein oxygen supplementing is carried out according to the process requirements during the grinding process of the air flow grinding device, and the online oxygen content of the air flow grinding device is kept between 0 and 50 ppm;
(4) Transferring the fine powder to a forming workshop, performing compression forming on the fine powder through a press to obtain a blank, packaging the blank with a vacuum packaging bag, and packaging with a vacuum packaging machine, wherein inert gas is always filled into the press in the compression forming process, and the oxygen content is always lower than 0.02%;
(5) The packaged blank is sent into a sintering film stripping glove box after being subjected to water isostatic pressing treatment, and the oxygen content in the sintering film stripping glove box is reduced to below 0.02 percent;
(6) In a sintering film peeling glove box, film peeling treatment is carried out on blanks, the blanks are taken out from a vacuum packaging bag and then are arranged in a sintering material box which is placed in the sintering film peeling glove box in advance, as shown in fig. 1 to 5, the sintering material box comprises a rectangular box body with an opening at the upper end, the rectangular box body is formed by splicing a front side plate 1, a rear side plate 2, a left side plate 3, a right side plate 4 and a bottom plate 5 according to the directions of front, rear, left and right sides, the front side plate 1, the rear side plate 2, the left side plate 3, the right side plate 4 and the bottom plate 5, a rectangular material cavity 6 for arranging the blanks is enclosed between the front side plate 1, the rear side plate 2, the left side plate 3, the right side plate 4 and the bottom plate 5, a first concave groove 7 which is downwards concave is arranged at the middle part of the upper end of the front side plate 1, a second concave groove 8 which is downwards concave is arranged at the middle part of the upper end of the rear side plate 2, a third concave groove 9 which is downwards concave is arranged at the middle part of the upper end of the left side plate 3, and a fourth concave groove 10 which is downwards concave is arranged at the middle part of the upper end of the right side plate 4; the front side plate 1, the rear side plate 2, the left side plate 3, the right side plate 4 and the bottom plate 5 are made of graphite;
(7) Under the protection of nitrogen, stacking the sintering material boxes filled with blanks up and down according to the furnace loading amount, covering a cover plate 12 on the uppermost sintering material box, wherein the cover plate 12 is made of graphite, and then arranging the stacked sintering material boxes in a furnace chamber of a sintering furnace in sequence by adopting a furnace-after-furnace feeding mode for high-temperature sintering, wherein the high-temperature sintering process adopts a vibration sintering process, and the specific process is as follows: heating for 30min to 430 ℃, repeating the cooling and heating process for 3 times, continuously heating for 90min to 600 ℃ and preserving heat for 1h, heating for 90min to 850 ℃ and preserving heat for 1h, continuously heating for 40min to 960 ℃ and preserving heat for 1.5h, then heating for 30min to 1060 ℃ and preserving heat for 4h, finally performing subsequent aging treatment, and discharging after the aging treatment is finished to obtain a sintered neodymium-iron-boron magnet, namely a rare earth permanent magnet material, wherein the cooling and heating process for each time is as follows: firstly cooling for 30min to 350 ℃, and then heating for 30min to 430 ℃.
In this embodiment, the cross sections of the first groove 7, the second groove 8, the third groove 9 and the fourth groove 10 along the vertical direction are isosceles trapezoids, and the lower bottoms of the isosceles trapezoids are located above the upper bottoms thereof.
In this embodiment, the height of the cross sections of the first groove 7, the second groove 8, the third groove 9 and the fourth groove 10 in the vertical direction is 3mm, the difference between the bottom and the upper bottom of the cross sections of the first groove 7, the second groove 8, the third groove 9 and the fourth groove 10 in the vertical direction is 50mm, the area of the cross section of the first groove 7 is 1% of the front side area of the rectangular cavity 6, the area of the cross section of the second groove 8 is 1% of the rear side area of the rectangular cavity 6, the area of the cross section of the third groove 9 is 1% of the left side area of the rectangular cavity 6, and the area of the cross section of the fourth groove 10 is 1% of the right side area of the rectangular cavity 6.
In this embodiment, the bottom of the bottom plate 5 is provided with a first annular groove 11, the depth of the first annular groove 11 is smaller than the depths of the first groove 7, the second groove 8, the third groove 9 and the fourth groove 10, and when a plurality of sintering cartridges are stacked up and down, the top of the front side plate 1, the rear side plate 2, the left side plate 3 and the right side plate 4 of the sintering cartridge located in the next layer is embedded into the first annular groove 11 provided at the bottom of the sintering cartridge located in the previous layer.
In this embodiment, the bottom of the cover plate 12 is provided with the second annular groove 13, the depth of the second annular groove 13 is smaller than the depths of the first groove 7, the second groove 8, the third groove 9 and the fourth groove 10, and when the cover plate 12 is disposed above the front side plate 1, the rear side plate 2, the left side plate 3 and the right side plate 4, the tops of the front side plate 1, the rear side plate 2, the left side plate 3 and the right side plate 4 can be embedded into the second annular groove 13.
In the present embodiment, the length of the front side plate 1 in the left-right direction is 500mm, the height in the up-down direction is 80mm, the thickness in the front-back direction is 5mm, the length of the rear side plate 2 in the left-right direction is equal to the length of the front side plate 1 in the left-right direction, the height of the rear side plate 2 in the up-down direction is equal to the height of the front side plate 1 in the up-down direction, and the thickness of the rear side plate 2 in the front-back direction is equal to the thickness of the front side plate 1 in the front-back direction; the length of the left side plate 3 in the front-rear direction is 300mm, the height in the up-down direction is 80mm, the thickness in the left-right direction is 5mm, the length of the right side plate 4 in the front-rear direction is equal to the length of the left side plate 3 in the front-rear direction, the height of the right side plate 4 in the up-down direction is equal to the height of the left side plate 3 in the up-down direction, and the thickness of the right side plate 4 in the left-right direction is equal to the thickness of the left side plate 3 in the left-right direction.
In this embodiment, during the high temperature sintering process, various impurity gases in the blank can be more rapidly and uniformly discharged through the first groove 7, the second groove 8, the third groove 9, and the fourth groove 10 in the sintering magazine. 8 sintered NdFeB magnets were selected at random positions after being discharged from the furnace and used as samples for testing magnetic properties and carbon content, and specific data are shown in Table 1.
Comparative example one: the present comparative example uses a conventional sintering process, and the sintering cartridge of example four is not used, but a conventional cartridge is used, and the other processes are the same as example four. 8 sintered NdFeB magnets of comparative example I were selected at random positions after tapping and used as samples for testing magnetic properties and carbon content, and specific data are shown in Table 2.
Table 1: example four sample magnetic Properties
Table 2: comparative example one sample magnetic Properties
As can be seen from an analysis of the data in tables 1 and 2: the sample four of example had a maximum remanence of 13.39 kGs, a minimum remanence of 13.31 kGs, a difference (. DELTA.B r) of 0.08 kGs, a maximum intrinsic coercivity H cJ of 20.60 kOe, a minimum H cJ of 20.24 kOe, and a difference (. DELTA.H cJ) of 0.36kOe. The sample of comparative example one had a maximum remanence of 13.37 kGs, a minimum remanence of 13.12 kGs, a difference (. DELTA.B r) of 0.25kGs, a maximum intrinsic coercivity H cJ of 20.54 kOe, a minimum H cJ of 19.82kOe, and a difference (. DELTA.H cJ) of 0.72kOe. Therefore, the blank residual magnetism and coercive force consistency of the fourth embodiment are improved, the carbon content is lower, the carbon content consistency is also obviously improved, and the consistency of the magnetic performance of the sintered NdFeB magnet is generally improved.
Fifth embodiment: a method for improving consistency of magnetic properties of rare earth permanent magnet materials comprises the following steps:
(1) Preparing materials according to the formula of a 45SH brand neodymium-iron-boron magnet, and obtaining cast sheets through a rapid hardening and sheet throwing technology;
(2) Hydrogen crushing the cast sheet to obtain alloy coarse powder, and then filling the alloy coarse powder into a tank body protected by inert gas for preservation;
(3) Transferring the alloy coarse powder into an air flow grinding device for grinding to obtain fine powder with the granularity D50 of 4.0-4.5 mu m, and then filling the fine powder into a tank body protected by inert gas, wherein oxygen supplementing is carried out according to the process requirements during the grinding process of the air flow grinding device, and the online oxygen content of the air flow grinding device is kept between 0 and 50 ppm;
(4) Transferring the fine powder to a forming workshop, performing compression forming on the fine powder through a press to obtain a blank, packaging the blank with a vacuum packaging bag, and packaging with a vacuum packaging machine, wherein inert gas is always filled into the press in the compression forming process, and the oxygen content is always lower than 0.02%;
(5) The packaged blank is sent into a sintering film stripping glove box after being subjected to water isostatic pressing treatment, and the oxygen content in the sintering film stripping glove box is reduced to below 0.02 percent;
(6) In a sintering film peeling glove box, film peeling treatment is carried out on blanks, the blanks are taken out from a vacuum packaging bag and then are arranged in a sintering material box which is placed in the sintering film peeling glove box in advance, as shown in fig. 1 to 5, the sintering material box comprises a rectangular box body with an opening at the upper end, the rectangular box body is formed by splicing a front side plate 1, a rear side plate 2, a left side plate 3, a right side plate 4 and a bottom plate 5 according to the directions of front, rear, left and right sides, the front side plate 1, the rear side plate 2, the left side plate 3, the right side plate 4 and the bottom plate 5, a rectangular material cavity 6 for arranging the blanks is enclosed between the front side plate 1, the rear side plate 2, the left side plate 3, the right side plate 4 and the bottom plate 5, a first concave groove 7 which is downwards concave is arranged at the middle part of the upper end of the front side plate 1, a second concave groove 8 which is downwards concave is arranged at the middle part of the upper end of the rear side plate 2, a third concave groove 9 which is downwards concave is arranged at the middle part of the upper end of the left side plate 3, and a fourth concave groove 10 which is downwards concave is arranged at the middle part of the upper end of the right side plate 4;
(7) Under the protection of nitrogen, stacking the sintering material boxes filled with blanks up and down according to the furnace loading amount, covering a cover plate 12 on the uppermost sintering material box, wherein the cover plate 12 is made of graphite, and then arranging the stacked sintering material boxes in a furnace chamber of a sintering furnace in sequence by adopting a furnace-after-furnace feeding mode for high-temperature sintering, wherein the high-temperature sintering process adopts a vibration sintering process, and the specific process is as follows: heating for 30min to 430 ℃, repeating the cooling and heating process for 3 times, continuously heating for 90min to 600 ℃ and preserving heat for 1h, heating for 90min to 850 ℃ and preserving heat for 2h, continuously heating for 40min to 960 ℃ and preserving heat for 1.5h, then heating for 30min to 1060 ℃ and preserving heat for 4h, finally performing subsequent aging treatment, and discharging after the aging treatment is finished to obtain a sintered neodymium-iron-boron magnet, namely a rare earth permanent magnet material, wherein the cooling and heating process for each time is as follows: firstly cooling for 30min to 350 ℃, and then heating for 30min to 430 ℃.
In this embodiment, the cross sections of the first groove 7, the second groove 8, the third groove 9 and the fourth groove 10 along the vertical direction are isosceles trapezoids, and the lower bottoms of the isosceles trapezoids are located above the upper bottoms thereof.
In this embodiment, the height of the cross sections of the first groove 7, the second groove 8, the third groove 9 and the fourth groove 10 in the vertical direction is 3mm, the difference between the bottom and the upper bottom of the cross sections of the first groove 7, the second groove 8, the third groove 9 and the fourth groove 10 in the vertical direction is 50mm, the area of the cross section of the first groove 7 is 1% of the front side area of the rectangular cavity 6, the area of the cross section of the second groove 8 is 1% of the rear side area of the rectangular cavity 6, the area of the cross section of the third groove 9 is 1% of the left side area of the rectangular cavity 6, and the area of the cross section of the fourth groove 10 is 1% of the right side area of the rectangular cavity 6.
In this embodiment, the bottom of the bottom plate 5 is provided with a first annular groove 11, the depth of the first annular groove 11 is smaller than the depths of the first groove 7, the second groove 8, the third groove 9 and the fourth groove 10, and when a plurality of sintering cartridges are stacked up and down, the top of the front side plate 1, the rear side plate 2, the left side plate 3 and the right side plate 4 of the sintering cartridge located in the next layer is embedded into the first annular groove 11 provided at the bottom of the sintering cartridge located in the previous layer.
In this embodiment, the bottom of the cover plate 12 is provided with the second annular groove 13, the depth of the second annular groove 13 is smaller than the depths of the first groove 7, the second groove 8, the third groove 9 and the fourth groove 10, and when the cover plate 12 is disposed above the front side plate 1, the rear side plate 2, the left side plate 3 and the right side plate 4, the tops of the front side plate 1, the rear side plate 2, the left side plate 3 and the right side plate 4 can be embedded into the second annular groove 13.
In the present embodiment, the length of the front side plate 1 in the left-right direction is 500mm, the height in the up-down direction is 80mm, the thickness in the front-back direction is 5mm, the length of the rear side plate 2 in the left-right direction is equal to the length of the front side plate 1 in the left-right direction, the height of the rear side plate 2 in the up-down direction is equal to the height of the front side plate 1 in the up-down direction, and the thickness of the rear side plate 2 in the front-back direction is equal to the thickness of the front side plate 1 in the front-back direction; the length of the left side plate 3 in the front-rear direction is 300mm, the height in the up-down direction is 80mm, the thickness in the left-right direction is 5mm, the length of the right side plate 4 in the front-rear direction is equal to the length of the left side plate 3 in the front-rear direction, the height of the right side plate 4 in the up-down direction is equal to the height of the left side plate 3 in the up-down direction, and the thickness of the right side plate 4 in the left-right direction is equal to the thickness of the left side plate 3 in the left-right direction.
In this embodiment, during the high temperature sintering process, various impurity gases in the blank can be more rapidly and uniformly discharged through the first groove 7, the second groove 8, the third groove 9, and the fourth groove 10 in the sintering magazine. 8 sintered NdFeB magnets were selected at random positions after being discharged from the furnace and used as samples for testing magnetic properties and carbon content, and specific data are shown in Table 3.
Comparative example two: the sintering magazine of example five was used in this comparative example, but a conventional sintering process was employed. 8 sintered NdFeB magnets of comparative example II were selected at random positions after being discharged from the furnace and used as samples for testing magnetic properties and carbon content, and specific data are shown in Table 4.
Table 3: example five sample magnetic Properties
Table 4: comparative example two sample magnetic Properties
From the data in tables 3 and 4, the maximum value of the residual magnetism of the sample in example five was 13.65kGs, the minimum value of the residual magnetism was 13.51kGs, and the difference (. DELTA.B r) was 0.14kGs. The intrinsic coercivity H cJ was a maximum of 21.95kOe, the H cJ minimum of 21.62kOe, and the difference (. DELTA.H cJ) was 0.33kOe. The sample of comparative example two had a maximum remanence of 13.61kGs, a minimum remanence of 13.40kGs and a difference (Δb r) of 0.21kGs. The maximum value of the intrinsic coercive force H cJ is 22.27kOe, the minimum value of H cJ is 21.39kOe, the difference (delta H cJ) is 0.88kOe, and at the moment, the oxygen content of the sample is generally increased, and the sample is easily oxidized, so that the magnetic performance is reduced. Therefore, the sintering process is combined with the proper range of the heights of the cross sections of the first groove 7, the second groove 8, the third groove 9 and the fourth groove 10 along the vertical direction, so that the consistency of the residual magnetism and the coercive force of the sintered NdFeB magnet can be improved, the carbon content is lower, the consistency of the carbon content is obviously improved, and the consistency of the magnetic performance of the sintered NdFeB magnet is generally improved.