JP2009252702A - Magnetic shield flange - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To shield a stray magnetic field up to an ultimate level with a vacuum seal of an ICF kept preserved, in relation to a magnetic shield flange interconnecting flanges formed on a pipe or vessel having a magnetic shield characteristic. <P>SOLUTION: The magnetic shield flange includes: magnetic shield flange parts each formed of a first material having a magnetic shield characteristic, and brought into press-contact with each other by a fixture; edge parts welded to the magnetic shield flange parts, vacuum-sealed by bringing gaskets into press contact therewith, and each formed of a second material not having a sufficient magnetic shield characteristic but capable of repeating sufficient press contact; first welding parts each formed at a predetermined width and a predetermined height in a part connected to the edge part and second welding parts each formed at the predetermined width and slightly higher than the predetermined height at a part connected to the magnetic shield flange part, in the inner parts of the edge part and the magnetic shield flange part at which both of them contact each other. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a magnetic shielding flange for mutually connecting flanges provided on pipes or containers having magnetic shielding properties.

  As the flange, there is a vacuum joint flange, for example, an international standard flat flange (ICF), which is used for an ultra high vacuum (UHV) related apparatus having internationally standardized dimensions. In particular, the present invention provides a vacuum seal through a gasket at the time of fixing with a flange portion made of PC (manufactured by Permalloy C having excellent magnetic shielding properties) in which the flanges of the ICF are vacuum-seal-connected with a plurality of screws. The present invention relates to a magnetic shielding flange characterized by having a SUS edge (a stainless steel edge resistant to repeated tightening) and having a magnetic shielding function by a PC, and an external magnetic field does not reach the vacuum inside the ICF.

  The magnetic shielding flange according to the present invention is used as a vacuum part for a low-speed electron beam apparatus (low acceleration SEM), a low-speed electron diffraction apparatus, a low-speed electron beam energy analyzer, and the like. These are essential in physical and chemical research fields such as surface analysis, material analysis, composite material development, and functional material analysis. In the industrial field, it is indispensable for manufacturing and quality control of minute composite materials, minute functional materials, minute parts and the like. In particular, it extends to the semiconductor field, the medical field that handles functional powders, and the energy (fuel cell material) field.

  Conventionally, the requirements for reliable vacuum sealing of ultra-high vacuum piping and ultra-high vacuum equipment are that the outgas is extremely small, the vacuum seal is reliable, and the position is reproducible during vacuum connection. As a vacuum joint that satisfies this requirement, there is an international standard ICF. ICF is generally made of SUS and satisfies the above requirements. That is, SUS has a feature that outgas is extremely small and changes due to oxidation of the surface are small and deformation is difficult.

  (1) Regarding SUS ICF: FIG. 1 shows an ICF that is a global standard. The material is SUS304 (one kind of stainless steel: JIS name, hereinafter referred to as SUS). In FIG. 1, reference numeral 1 denotes a rotational symmetry axis imaginary line. When ICF3 and ICF4 facing each other are coupled by screw 1 and nut 2 or screw tightening that can be developed around a predetermined (plurality of) flanges via a copper gasket 10, the edge 7 of the ICF bites into the gasket 10 and a vacuum seal is formed. Obtainable. Since the gasket 10 is fitted in the fitting portion 9, a portion surrounded by the edge 7, the edge inclined portion 8 and the fitting portion 9 applies high pressure to the gasket 10, and the edge 7 and the gasket 10 are vacuum-sealed. The gasket 10 digging into the edge 7 obtains a high vacuum sealing property at the edge 7 and the edge inclined portion 8. At this time, the fitted gasket 10 ensures the reproducibility of the positions of both flanges at the fitting portion 9. Thus, the vacuum pipe or the vacuum equipment outer cylinder is vacuum-sealed to form a connection. Hereinafter, piping or vacuum equipment outer cylinders connected to the ICF will be omitted from the drawings, and only the ICF will be described.

  In addition, there are many cases in which a different kind of gasket 11 that performs vacuum sealing at the inclined portion 8 of the edge of the ICF is used without using the edge for vacuum sealing ((d) in FIG. 1).

  In either case, the gasket is deformed because it is deformed, but the ICF itself is made of SUS, and there is no deformation of the edge and the inclined portion of the edge, and it can be used permanently.

However, the initial permeability μ _i of SUS is extremely small (μ _i = about 1), and the stray magnetic field passes through the ICF and reaches the inside of the vacuum. Devices such as low-speed electron beams that operate in a vacuum system are affected by stray magnetic fields. That is, according to electromagnetism, the force applied to the electrons is expressed by the vector product of the velocity and the magnetic flux density as shown in the following equation, and the electron beam is bent according to this.

mα = -e ・ v × B
Where m is the mass of the electron (9.1 x 10 ^-31 kg)
α: Acceleration vector of electrons (m / sec ² )
e: Electronic charge (1.6 × 10 ^-19 Coul)
v: electron velocity vector (m / sec)
B: Magnetic flux density vector (Teslar)
That is, an electron beam with a magnetic flux density B having a direction perpendicular to the traveling direction of the electron beam forms a circular orbit with a radius ρ on a plane perpendicular to both.

ρ = (m * v) / (e * B) (Formula 1)
Where ρ: orbital radius of rotation (m)
According to (Equation 1), for example, when the electron beam energy is reduced by two orders of magnitude, the speed is reduced by one order of magnitude, so ρ is reduced by one order of magnitude.

  In the case of a low-speed electron beam irradiation device, it reacts sensitively to the external magnetic field by (Equation 1), impairing its resolution, the electron beam vibrates at the landing point, the electron beam itself does not warp and arrives at the landing point, etc. Cause problems. The same problem occurs in measuring devices such as an electron beam energy analyzer. The degree is inversely proportional to the 1/2 power of the electron beam energy and proportional to the disturbance magnetic field. Therefore, the lower the acceleration, the greater the effect.

  For example, if a 100 eV electron beam traveling straight is subjected to a magnetic flux density of 400 Gauss (approximately the magnitude of geomagnetism) in a direction perpendicular to the traveling direction, a motion trajectory having a rotational radius of about 0.84 m is given to the electron beam, Its straightness is significantly hindered. As a result, the electron beam is disturbed, a predetermined trajectory with the electron lens cannot be obtained, and problems such as disappearance of the electron beam itself occur.

  In particular, in devices that handle low-acceleration electron beams, a method of covering the periphery of the device with a magnetic shield is used, but it is generally a great effort to place a magnetic shield material on the outer periphery of a complicated shape. Cost. In addition, there are portions where this cannot be performed due to restrictions due to piping holes, wiring, and the shape of the apparatus, and there is a problem that it is difficult to provide a perfect magnetic shield without any joints.

(2) About PC ICF: On the other hand, if ICF3, 4 etc. are made using a high magnetic shield material, for example, PC (Permalloy C: JIS standard name) having μ _i = 30,000 or more, the magnetic shield characteristics after ICF formation As a result of magnetic annealing (maximum of about 1,050 ° C.) determined by the manufacturer in order to optimize the hardness, the hardness is considerably soft as 129 HV, and the portion to be vacuum sealed with the copper gasket 10, that is, the edge 7 and the edge of the PC ICF This causes a problem that the inclined portion 8 is deformed and the function of the vacuum seal is lost.

Further, when the magnetic annealing is performed at a low temperature of 850 ° C., the hardness is sufficiently high from 159 HV to 165 HV, and a vacuum sealing function can be achieved without causing deformation, but the initial permeability μ _i at this annealing temperature is 30,000 or more. Is not guaranteed at all, and there is a problem that sufficient magnetic shielding cannot be obtained.

  In order to solve these problems, the present invention is a magnetic shielding flange for connecting flanges provided on pipes or containers having magnetic shielding properties to each other, and is formed of a first material having magnetic shielding properties, and a fixture. The second material that does not have sufficient magnetic shielding properties but is capable of repeated sufficient pressure welding, which is welded to the magnetic shielding flange portion and welded to the magnetic shielding flange portion and vacuum-sealed by pressing the gasket. And a brazing part provided with a first gap for placing a brazing to be welded, and a brazing part placed on the brazing part. And a wax reservoir having a second gap provided inside the first gap and having a smaller gap, which is drawn in and collected by surface tension when melted.

  In addition, the magnetic shielding flange is formed of a first material having magnetic shielding properties, welded to the magnetic shielding flange portion and welded to the magnetic shielding flange portion with a fixture, and has a sufficient magnetic shielding property for vacuum-sealing by pressing the gasket. The edge part made of the second material that does not have sufficient but can be repeatedly welded, and the inner part of both the edge part and the magnetic shielding flange part are in contact with each other. The first welded portion and the second welded portion are provided, and the same material as the second material or sufficient magnetic shielding properties are provided at the tip portions of both the first welded portion and the second welded portion. However, a material that can be repeatedly welded sufficiently is melted and raised to be welded.

  In addition, the magnetic shielding flange is formed of a first material having magnetic shielding properties, welded to the magnetic shielding flange portion and welded to the magnetic shielding flange portion with a fixture, and has a sufficient magnetic shielding property for vacuum-sealing by pressing the gasket. The edge part made of the second material that does not have a sufficient pressure but can be repeatedly repeated, and the inner part where the edge part and the magnetic shielding flange part are in contact with each other, the part connected to the edge part with a predetermined width A first welded portion formed at a height and a second welded portion formed at the predetermined width and slightly higher than the predetermined height at a portion connected to the magnetic shielding flange portion, and slightly higher than the second welded portion. The part is melted and welded to the first weld.

  In these cases, the second gap is gradually reduced from the width of the first gap.

  Further, the predetermined height of the first welded portion is set to a range of 1 to 3 times the predetermined width, and the predetermined height of the second welded portion is set to the predetermined height of the first welded portion, Furthermore, a range of 1 to 2 times the predetermined width is added.

  Further, after welding the first material and the second material, the temperature is lowered to a predetermined temperature for annealing the first material, and then the temperature is lowered to make the first material a high magnetic shielding material. .

  Further, the material of the magnetic shielding flange portion is Permalloy C, and the material of the edge portion is SUS.

The present invention provides an ICF having a magnetic shield by welding a SUS edge portion to a flange portion made of PC or silver brazing, or welding SUS made of the same material as the edge portion and welding them together. The stray magnetic field can be shielded to the extreme while maintaining the ICF vacuum seal. As a result, the trajectory of the low-speed electron beam useful for surface analysis and the like can be maintained.

  The present invention provides an ICF having a magnetic shield by welding a SUS edge portion to a flange portion made of PC or silver brazing, or welding SUS made of the same material as the edge portion and welding them together. , It was possible to shield the stray magnetic field to the ultimate while maintaining the ICF vacuum seal.

  FIG. 1 is an explanatory view of a flange.

  (A) of FIG. 1 shows the schematic explanatory drawing of a flange. The illustrated flange schematically shows the upper cross section around a virtual axis of one rotation symmetry.

  In FIG. 1 (a), a screw 1 and a nut 2 are coupled to each other by connecting the screw 1 to the nut 2 and rotating and tightening the two to make an ICF (International Conflat Flange). (Flange, ICF) 3 and 4 are fixed in a state of being in close contact with each other.

  The ICFs 3 and 4 are flanges for holding the ultrahigh vacuum by pressing the gasket 10 with the edge 7 constituting the flange. Here, the shape of the edge inclined portion 8 plays a role of more reliably maintaining the airtightness by the gasket 10 and the edge 7.

  The vacuum pipe or vacuum equipment outer cylinder 5 is a pipe or container connected to the ICFs 3 and 4.

  The edge 7 is for holding the ultrahigh vacuum by pressing the gaskets 10 against each other.

  The edge inclined portion 8 is an inclined portion for forming the edge 7.

  The fitting portion 9 is a portion configured such that the ICFs 3 and 4 facing each other are fitted to each other in such a manner that the gaskets 10 are pressed against each other.

  FIG. 1B shows a state in which the flange having the structure shown in FIG. 1A is fixed in such a manner that a plurality of sets of screws 1 and nuts 2 are pressed against each other. In this state, the gasket 10 is fixed in a state in which the positions facing each other at the edges 7 of the ICFs 3 and 4 are pressed against each other and an ultrahigh vacuum is maintained. The gasket 10 can be used repeatedly using pure copper or the like.

  (C) of FIG. 1 shows the state fixed using the different kind of gasket 11. FIG. The different type gasket 11 in the state shown in FIG. 1 is fixed in a state in which the gasket 10 in FIG. 1 (b) is pressed against the tip of the edge 7 and can maintain an ultra-high vacuum, whereas FIG. 7 and is fixed in a state in which an ultra high vacuum can be maintained by pressure contact with an edge inclined portion 8. In any case, it suffices that a part of one of the gaskets 10 and 11 facing each other is locally pressed so as to maintain an ultrahigh vacuum.

  Using the ICFs 3 and 4 having the above configuration, the opposing locations of the gaskets 10 and 11 are pressed against each other by the edge 7 or the edge inclined portion 8 constituting the ICFs 3 and 4 to maintain an ultra-high vacuum (ultra-high pressure). That is, it is fixed so that the leakage is kept extremely small. At this time, when the ICFs 3 and 4 are made of a material having high magnetic shielding (referred to as “first material”, for example, Permalloy C), the material having high magnetic shielding is formed as the edge 7 and the edge inclined portion 8. There is a problem that the hardness is not sufficient, the edge 7 and the edge inclined portion 8 are sagged and the airtightness cannot be sufficiently maintained, and the repeated use is impossible.

  In order to solve this problem, the present invention adopts the structure and processing method described in FIG. Details will be sequentially described below.

  FIG. 2 is an explanatory diagram (part 1) of the present invention. FIG. 2 shows an example of silver brazing.

  (A) of FIG. 2 shows the schematic explanatory drawing of this invention.

  (A-1) in FIG. 2 shows the overall configuration, and (a-2) in FIG. 2 shows an enlarged view of the SUS edge 22 and its vicinity.

  In FIGS. 2A-1 and 2A-2, the PC flange 21 is a flange made of Permalloy C, which is a material having a sufficiently high magnetic shielding.

  The SUS edge 22 is a flange made of SUS, which is a material having a sufficiently high hardness, although the magnetic shielding as the edge is not sufficiently high.

  The fitting portion 23 is a portion that fits by fitting the SUS edge 22 to the PC flange 21 in the radial direction.

  The mating surface 24 is a surface for aligning the SUS edge 22 with the PC flange 21 in the axial direction.

  The silver solder reservoir 25 is a part in which the silver solder placed in the silver solder holder 26 melts and is drawn in by surface tension to store the silver solder. The melted silver solder is drawn by the surface tension force into the contact portion between the SUS edge 22 and the PC flange 21 and the remaining silver wax remains in the silver solder reservoir 25 or the silver solder holder 26. Will be. The gap of the silver brazing reservoir 25 may be a gap sufficient for the melted silver wax to be drawn by surface tension, for example, about 0.1 to 0.5 mm.

  The silver wax placing part 26 is a place where a silver wax is placed. With the silver solder placed in the silver solder holder 26 and the PC flange 21 and the SUS edge 22 fixed with gravity or a jig, the whole is heated to a temperature at which the silver solder melts, and the melted silver solder In the same manner, the surface tension force draws the contact portion between the SUS edge 22 and the PC flange 21 through the silver solder reservoir 25 by the surface tension force. Then, by cooling, the SUS edge 22 is silver brazed to the PC flange 21, and a connection that can withstand ultra-high vacuum is made (details will be described later with reference to the flowchart of FIG. 5).

  FIG. 2B shows an enlarged view of the vicinity of the SUS edge 22 in FIG.

  2B-1 shows a state where the silver solder 27 is placed on the silver solder holder 26, and FIG. 2B-2 shows a situation where the silver solder melts and the silver solder reservoir 25 and the silver solder holder 26. Shows the state of accumulation.

  2 (b-1), the silver solder 27 shows a state in which a flat ring-shaped silver solder is placed on the silver solder holder 26 shown in FIG. 2 (a-2).

  In (b-2) of FIG. 2, the melted silver solder 28 is heated in the state of (b-1) of FIG. 2 to melt the silver solder 27. The reservoir 25 and the SUS edge 22 are drawn into the portion in contact with the PC flange 21 to be soldered with silver, and the remaining silver solder remains in the silver solder holder 26 and is solidified.

  As shown in FIGS. 2A and 2B described above, in the state where the silver solder is placed in the silver solder placing portion 26, the whole is heated to melt the silver solder and is made of SUS by the force of surface tension. It is possible to braze the edge 22 to the portion where the PC flange 21 is in contact, and the remaining silver solder is retained in the silver solder reservoir 25 and further in the silver solder holder 26, so that sufficient silver solder can be obtained. Can be supplied to the joint surface between the SUS edge 22 and the PC flange 21 to completely braze the silver.

  FIG. 2C shows another example.

  FIG. 2 (c-1) shows a structural example in which the width of the silver solder reservoir 25 is gradually narrowed from the width of the silver solder holder 26. By providing the structure shown in the figure, when the silver wax placed in the silver solder placing portion 26 melts, all of the melted silver solder is easily attracted in the direction of the silver solder reservoir portion 25 by the force of surface tension. Thus, it is possible to prevent silver brazing from being performed at unnecessary locations.

  (C-2) of FIG. 2 shows a structural example in which baffle plates 28 and 29 are arranged outside the silver brazing part 26 so that the melted silver wax does not evaporate outside. By using the structure shown in the figure, when the silver solder placed in the silver solder holder 26 is melted, it is prevented from evaporating to the outside and sticking to an unnecessary place or being guided to the outside through the surface. In addition, it is possible to reduce the work of removing the silver brazing adhered to the unnecessary place after the silver brazing.

  FIG. 3 is an explanatory diagram (part 2) of the present invention. FIG. 3 shows an example in which a SUS welding rod is melted in the welded portion 35 between the SUS edge 32 and the PC flange 31 to weld them together.

  (A) of FIG. 3 shows the schematic explanatory drawing before welding.

  In FIG. 3A, a PC flange 31 is a flange made of Permalloy C having high magnetic shielding.

  The SUS edge 32 is an edge made of SUS having high hardness.

  The fitting portion 33 is a portion where the SUS edge 32 is fitted to the PC flange 31 in the radial direction.

  The mating surface 34 is a surface for aligning the SUS edge 32 with the PC flange 31 in the axial direction.

  The welded portion 35 is a convex welded portion formed in substantially the same shape on both the SUS edge 32 and the PC flange 31, and has a width a, a height b (PC flange 31 side), and a height c ( SUS edge 32 side), and these relations have the following relations.

b, c = a × (1-3) (Equation 2)
Here, b and c are the heights of the PC flange 31 side and the SUS edge 32 side, and a is the width of both. That is, it is desirable that the heights b and c on the PC flange 31 side and the SUS edge 32 side be created within a range of 1 to 3 times the width. The welded portion 35 created within this range is a range in which good welding is performed when another SUS welding rod is melted and welded to the welded portion 35. Although the width is the same in both cases, if the width is made different, the width should be widened so that when the SUS is melted and raised at the tip of the welded portion 35, it is heated to substantially the same temperature. You may adjust so that height may be made low if height is high and conversely narrowing width. This width gives the strength of the joint after welding. For example, if the ICF has a diameter of 70 mm, about 1 to 1.5 mm is sufficient.

  The stress relief portion 36 is a gap provided in a portion where the fitting portion 33 and the mating surface 34 are joined, and the mating surface is obtained by a force (stress) applied when the welded portion 35 returns to room temperature after being welded. 34, for allowing a situation in which the fitting portion 33 is separated or displaced from each other.

FIG. 3B schematically shows a state after SUS is melted and welded under the structure of FIG.

  In FIG. 3 (b), the joint portion 37 shows one cross section after being welded for one round for the first time from a certain point so as to have a substantially semicircular shape while melting SUS. Here, swelling the SUS welding rod into a substantially semicircular shape in the welded portion 35 of FIG. 3A is welded over one turn for the first time from a certain point, and a cross-sectional view of the point is shown in the illustrated welded portion. 36 (details will be described later with reference to FIG. 6).

  As described above, the welding portion 35 shown in FIG. 3 (a) is provided, and welding is performed over the entire circle for the first time from the point that the SUS welding rod is being melted in a semicircular shape on the welding portion 35. 3 (b) can be raised and welded (SUS rich welding) to the welded portion 35 in which the PC flange 31 and the SUS edge 32 are in contact with each other. Here, a SUS welding rod is melted and raised to a semicircular shape in the welded portion 35 to form a joint 36 (SUS rich joint 36). On the contrary, when PC (Permalloy C) is melted and the welded portion 35 is raised in a semicircular shape to form a joint 36 (PC-rich joint 36) and welded together, the cracks are caused after cooling. As a result, good results that can withstand ultra-high vacuum could not be obtained. Here, when the SUS rich joint portion 36 is formed, the joint portion 36 is not cracked after being subjected to magnetic annealing (about 1050 ° C.) after welding.

  In addition, when forming the joint part 37 by welding up a welded part, SUS is very good compatibility as described above, but the PC part and the PB material are welded up to form the joint part 37. In the case of welding, good welding results cannot be obtained. This is because the SUS edge 32 side of the joint 37 is SUS rich, and as it reaches the PC flange 31 side, the SUS component gently fades to become PC rich, and further connected to the PC flange 31 which is the PC base material. It is thought that there is.

  Further, the width a of the welded portion 35 determines the thickness of the welded portion 35, and if the thickness is thick, the strength is strong, and if the thickness is thin, the strength is weak. The heights (welding allowances) b and c of the welded portion 35 serve to extremely reduce the probability of occurrence of cracks and the like in the joint portion 36 and the welded portion 35 by relaxing thermal stress during welding and magnetic annealing. . In actual use, it is used as an ultra-high vacuum device, and in order to obtain an ultra-high vacuum, a vacuum is drawn while baking out (depending on the purpose, 150 ° C. to 250 ° C.). However, in the case of the SUS rich joint 36 described above, problems such as vacuum leakage and deformation do not occur.

  Further, if the height (welding allowance) b, c of the welded portion 35 is made too short, heat conduction from the welded portion 35 to the periphery increases, and it is difficult to sufficiently raise the temperature of the welded portion 35 with a limited amount of heat. Therefore, it becomes difficult to obtain sufficient bonding strength.

  FIG. 4 shows an explanatory diagram (part 3) of the present invention. FIG. 4 shows an example in which the height of the welded portion 45 between the SUS edge 42 and the PC flange 41 is made different to melt the higher SUS and weld them together. In particular, in the case of welding in a narrow space, in the example of FIG. 3, a certain amount is melted and raised to a semicircular shape while pressing the raised SUS rod against the welded portion 55 for a first time from a certain point. However, if the raised SUS rod shown in FIG. 4 is not used, welding can be simplified. This will be described in detail below.

  (A) of FIG. 4 shows the schematic explanatory drawing before welding.

  4A-1 is an overall cross-sectional view, and FIG. 4A-2 is an enlarged view of the SUS edge 42 portion.

  In (a-1) and (a-2) of FIG. 4, the PC flange 41 is a flange made of Permalloy C having high magnetic shielding.

  The SUS edge 42 is an edge made of SUS having high hardness.

  The fitting portion 43 is a portion that fits by fitting the SUS edge 42 to the PC flange 41 in the radial direction (any one may be used).

  The mating surface 44 is a surface for aligning the SUS edge 42 with the PC flange 41 in the axial direction.

  The welded portion 45 is a convex welded portion formed by increasing the height of the SUS edge 42 and decreasing the height of the PC flange 41, and has a width a and a height b (on the PC flange 41 side). ), A portion having a height c (SUS edge 42 side), and these relations have the following relations.

b = a × (1-3)
c = b + a × (1-2) (Equation 3)
Here, b and c are the heights of the PC flange 41 side and the SUS edge 42 side, and a is the width of both. That is, the height b on the PC flange 41 side is desirably created in the range of 1 to 3 times the width a. It is desirable that the height c on the SUS edge 42 side is created within a range of height obtained by adding 1 to 2 times the width to the height b on the PC flange 41 side. In the welded portion 45 created within this range, a range in which satisfactory welding is performed when SUS of the base material of the high SUS edge 42 described later is melted and the welded portion 45 is welded to a semicircular shape. It is. Although the widths are the same in both cases, if they are different, the SUS of the base material of the high SUS edge 42 is melted and raised at the tips of the welded portions 45 of both, and heated to substantially the same temperature. Thus, the height may be adjusted to be higher if the width is increased, and the height may be decreased if the width is decreased.

  It should be noted that the height of the overlength portion (a portion where c is higher than b) of (Equation 3) (the portion where c is higher than b) is just welded in a semicircular shape by melting the overlength portion. The height is determined by experiment so that it can be done.

  FIG. 4B shows an example in which the direction of the welded portion 45 in FIG. 4A is changed to a radial welded portion 55. Since others are the same, description is abbreviate | omitted.

  FIG. 5 shows a flowchart (part 1) for explaining welding according to the present invention. This is a flowchart illustrating the welding of FIG.

  In FIG. 5, S1 processes a flange part and an edge part. This processes the PC flange 21 and the SUS edge 22 of FIG.

  In S2, borax is applied. This applies borax to the welded portions of the PC flange 21 and the SUS edge 22 of FIG. 2 processed in S1. For example, a material obtained by dissolving borax in water (actually, a welding auxiliary material in which a material for improving welding is mixed into borax) is subjected to silver brazing, as shown in FIG. It is applied to the reservoir 25, the silver brazing part 26, and the silver brazing 27.

  S3 fits and puts silver wax. This is because, as shown in FIG. 2 (b-1), silver is applied to the PC flange 21 in a state in which force is applied in the direction in which the SUS edges 22 are brought into close contact with each other by gravity or a jig. A wax 27 (for example, a ring shape) is placed in the silver wax holder 26. Note that the amount of silver wax is determined in advance by experiments so that the silver wax does not adhere to unnecessary portions.

  S4 is heated to 600 ° C. order in a furnace. In S1 to S3, the SUS edge 22 is attached to the PC flange 21, and the whole is heated to about 600 ° C. with the silver solder 27 placed in the silver solder holder 26.

  In S5, it is confirmed that the silver wax has melted, and the temperature is lowered. This is because the whole is heated in S4 to melt the silver wax 27 of (b-1) of FIG. 2, and the melted silver wax is replaced with the silver wax placing portion 26, as shown in (b-2) of FIG. After confirming that the silver brazing reservoir 25, the fitting portion 23, and the mating surface 24 have been distributed by surface tension, the temperature is lowered.

  S6 completes welding. The welding is completed when the temperature of S5 drops to room temperature. The PC flange 41 is previously annealed.

  After processing the PC flange 21 and the SUS edge 22 in FIG. 2 and putting the silver solder 27 in the silver solder holder 26 as shown in FIG. 2 (b-1), the whole is heated. By melting the silver solder, the PC flange 21 and the SUS edge 22 can be welded by silver brazing.

  FIG. 6 shows a welding explanation flowchart (No. 2) of the present invention. This is an explanatory view for explaining the welding in FIG. 3.

  In FIG. 6, S11 processes a flange part and an edge part. This processes the PC flange 31 and the SUS edge 32 of FIG.

  S12 fixes both with gravity or a jig. This fixes the portion to be welded of the PC flange 31 and the SUS edge 32 of FIG. 3 processed in S11 so that force is applied in the direction in which they are brought into close contact with each other by gravity or a jig.

  In S13, one round welding is performed for the first time from one point while applying a SUS material for prime. This is because an arc is generated by electric welding while blowing an inert gas (for example, argon) on the welded portion 35 in FIG. 3, and the same material as the SUS edge 32 is formed on the welded portion 35 heated by the arc. A SUS rod is brought close and melted, raised to a semicircular shape and welded. At this time, the SUS material is melted from one point of the welded portion 35 and continuously formed over one round while being raised in a semicircular shape, and the welding is finished after returning to the first point.

  S14 is magnetically annealed. This performs known magnetic annealing on the PC edge 32 so that the original magnetic characteristics of the PC are exhibited (see FIG. 9).

  S15 completes welding.

  By processing the PC flange 31 and the SUS edge 32 in FIG. 3 and melting the SUS in the welded portion 35 and raising it into a semicircular shape, the PC flange 31 and the It becomes possible to weld the SUS edge 32 with SUS.

  FIG. 7 shows a welding explanation flowchart (part 3) of the present invention. This is a flowchart illustrating the welding of FIG.

  In FIG. 7, S21 processes a flange part and an edge part. This processes the PC flange 41 and the SUS edge 42 of FIG.

  S22 fixes both with gravity or a jig. This is because, after applying borax to the welded portions of the PC flange 41 and the SUS edge 42 of FIG. 4 processed in S21, a force is applied in a direction in which the two are brought into close contact with each other by gravity or a jig. Secure to.

  In S23, welding is performed using the over-long portion of SUS as a margin. This is because an arc is generated by electric welding in a reducing atmosphere while blowing an inert gas (for example, argon) on the welded portion 45 in FIG. 4A-2, and the welded portion 45 heated by the arc is heated. The long overlong portion (excess portion of the SUS edge 42) is melted and welded into a semicircular shape. At this time, the overlength portion is melted from one point of the welded portion 45 to make a semicircular shape continuously, and the welding is finished after returning to the first point.

  S24 performs magnetic annealing. This performs a known magnetic annealing on the PC flange 41 so as to exhibit the original magnetic characteristics of the PC (see FIG. 9).

  S25 completes welding.

  As described above, the PC flange 41 and the SUS edge 42 in FIG. 4 are processed, and the over-long portion (SUS) of the SUS edge 2 of the welded portion 45 is melted to form a semicircular shape for the first time from one point. By welding, the PC flange 41 and the SUS edge 42 can be welded with SUS which is a base material of the SUS edge 42.

  FIG. 8 shows a welded cross section of the present invention. The cross-sectional view of FIG. 8 shows a micrograph of a cross-section in which the test piece processed into the structure of FIG. 4 described above is welded according to the flowchart of FIG. 7 described above and the welded surface is cut after welding.

  In FIG. 8, SUS is stainless steel (SUS304), and the height of the welded portion is initially (before welding) and is formed to be higher than the height of the PC by about the width (c in (Equation 3)). Height range).

  PC is permalloy (permalloy C), and the height of the welded portion is initially (before welding) and is formed to be lower than the height of SUS by about a width (the height of b in (Equation 3)). Range).

  The welded part is welded over a circle for the first time from a certain point in a shape where the part formed higher by the width of SUS is melted by welding and raised to the joint part of SUS and PC as shown in the figure. It is the microscope picture of what was cut (refer the flowchart of FIG. 7, and its description).

  The stress relief portion is a gap for reducing stress (distortion) due to a difference in coefficient of thermal expansion of each portion when the welded welded portion is cooled.

  Note that the widths of SUS and PC constituting the welded portion are about 1 mm in width and about 2 mm and 1 mm in height, respectively.

  As can be seen from the photograph of the cross section of the welded portion, it has been found from the photograph that satisfactory welding is possible by melting SUS and raising the SUS and PC joint as shown in the figure. Conversely, when PC is melted and raised at the joint between PC and SUS, good welding is impossible, cracking occurs after cooling, etc., and it cannot be used for welding ultra-high vacuum flanges. Met.

  FIG. 9 is an explanatory diagram of the present invention.

  FIG. 9A shows an example of the physical characteristics of permalloy and SUS.

  In FIG. 9A, permalloy is PC. PB and the like are as shown in the figure, and have characteristics that the initial permeability is extremely high and magnetic shielding is effective. On the other hand, the hardness HV is low, for example, 129 HV (PC when annealed at 1050 ° C. to improve the initial magnetic permeability) and cannot be used for the edge of the ICF described above.

  SUS includes 304, 316, 310, etc. Usually, the initial magnetic permeability is extremely small compared to permalloy, and there is a characteristic that is not effective for magnetic shielding. On the other hand, the hardness HV is high. For example, even when permalloy is annealed at 1050 ° C. to improve the initial permeability, it is 156 HV (SUS304), and can be used for the ICF edge described above, and has physical characteristics that can withstand repeated operations. It is what.

  FIG. 9B shows an explanatory diagram of conditions under which both the hardness HV and the magnetic permeability characteristics are established.

In FIG. 9B,
(1) SUS alone is not magnetically established.

  (2) With PC alone, magnetic annealing can be used if magnetic annealing is performed at 850 ° C.

  (3) 1050 ° C. annealing is established by a combination of PC and SUS.

  In the present invention, the combination of PC and SUS (3) ensures a sufficient initial permeability in the PC even when annealing is performed at an annealing temperature of 1050 ° C. which increases the initial permeability of the PC. The initial permeability of the PC flanges 21, 31, 41 is extremely high to increase the magnetic shielding, and the hardness of the SUS edges 22, 32, 42 of FIGS. It is possible to create an ICF with good magnetic shielding by brazing silver and welding and welding the welded portions 35 and 45 with SUS.

  The present invention provides an ICF having a magnetic shield by welding or silver brazing a SUS edge portion to a PC flange portion or welding SUS made of the same material as the edge portion as a welding material. The present invention relates to a magnetic shielding flange that shields stray magnetic fields to the ultimate while preserving them.

It is explanatory drawing of a flange. It is explanatory drawing (the 1) of this invention. It is explanatory drawing (the 2) of this invention. It is explanatory drawing (the 3) of this invention. It is a welding explanatory flowchart (the 1) of this invention. It is a welding explanatory flowchart (the 2) of this invention. It is a welding explanatory flowchart (the 3) of this invention. It is the welded sectional view of the present invention. It is explanatory drawing of this invention.

Explanation of symbols

1: Screw 2: Nut 3, 4: ICF
5, 6: Vacuum piping or vacuum equipment outer cylinder 7: Edge 8: Edge inclined part 9: Fitting part 10: Gasket 11: Different types of gaskets 21, 31, 41, 51: PC flanges 22, 32, 42, 52: SUS edges 23, 33, 43, 431, 53: mating parts 24, 34, 44, 54, 54: mating surface 25: silver solder reservoir 26: silver solder holder 27: silver solder 28: melted silver solder 29: baffle plates 35, 45, 55: welded portion 36: joined portion

Claims (8)

In the magnetic shielding flange that connects the flanges provided in pipes or containers having magnetic shielding properties to each other,
A magnetic shielding flange portion formed of a first material having magnetic shielding properties and pressed against each other by a fixture;
An edge portion made of a second material that does not have sufficient magnetic shielding properties but is sufficient to repeat the above-mentioned pressure welding, for welding to the magnetic shielding flange portion and vacuum-sealing the gasket.
A bracing part provided with a first gap for placing a brazing to be welded on the inner part of both the edge part and the magnetic shielding flange part,
And a wax reservoir having a second gap provided inside the first gap and having a small gap, which is pulled in and collected by surface tension when the wax placed in the wax holder is melted. Magnetic shielding flange. In the magnetic shielding flange that connects the flanges provided in pipes or containers having magnetic shielding properties to each other,
A magnetic shielding flange portion formed of a first material having magnetic shielding properties and press-contacted with each other by a fixture;
An edge portion made of a second material that does not have sufficient magnetic shielding properties but is capable of repeating sufficient pressure welding;
A first welded portion and a second welded portion having a predetermined width and a predetermined height are provided on the inner portions of the edge portion and the magnetic shielding flange portion in contact with each other,
Dissolve the same material as the second material, or a material that does not have sufficient magnetic shielding properties but can be repeatedly welded, at the tip of both the first welded portion and the second welded portion. Magnetic shielding flange characterized by being raised and welded. In the magnetic shielding flange that connects the flanges provided in pipes or containers having magnetic shielding properties to each other,
A magnetic shielding flange portion formed of a first material having magnetic shielding properties and press-contacted with each other by a fixture;
An edge portion made of a second material that does not have sufficient magnetic shielding properties but is capable of repeating sufficient pressure welding, welded to the magnetic shielding flange portion and vacuum-sealed with a gasket;
A first welded portion formed at a predetermined width and a predetermined height at a portion connected to the edge portion, and a portion connected to the edge portion and the magnetic shielding flange portion, and the magnetic shielding flange portion. A second weld portion formed in the portion with the predetermined width and slightly higher than the predetermined height,
A magnetic shielding flange, wherein a slightly high portion of the second welded portion is melted and welded to the first welded portion.   The magnetic shielding flange according to claim 1, wherein the second gap is gradually reduced from the width of the first gap.   3. The magnetic shielding flange according to claim 2, wherein the predetermined height is in a range of 1 to 3 times the predetermined width.   The predetermined height of the first welded portion is in the range of 1 to 3 times the predetermined width, and the predetermined height of the second welded portion is set to the predetermined height of the first welded portion. The magnetic shielding flange according to claim 3, further comprising a range of 1 to 2 times the predetermined width.   After welding the first material and the second material, the temperature is raised to a predetermined temperature for annealing the first material, and then the temperature is lowered to make the first material a high magnetic shielding material. The magnetic shielding flange according to claim 1, wherein the magnetic shielding flange is a magnetic shielding flange.   The magnetic shielding flange according to any one of claims 1 to 7, wherein the first material is Permalloy C, and the second material is SUS.

Images