JPH06182926A - Electromagnetic structural cladding material - Google Patents

Abstract

PURPOSE:To provide an electromagnetic structural cladding material in which mechanical strength, rigidity, thermal shrinkage are optimized and particularly a superconducting magnet-supporting collar material for a particle accelerator by laminating and integrating different type nonmagnetic materials having different thermal shrinkages. CONSTITUTION:An electromagnet supporting structural cladding material is formed by laminating and integrating a nonmagnetic steel on both or one side surface of an Al alloy material by intermetallic connection in such a manner that a tensile strength is 50kgf/mm<2> or more, a Young's modulus is 10000kgf/ mm<2> or more, a specific penneability is 1.002 or less, a thermal expansion (shrinkage) coefficient at 4K is 0.33% or less, a thickness is 0.5-5mm, and a thickness ratio of the Al material to the steel is 0.3-2.5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stainless steel-Al clad material used at extremely low temperatures, and more particularly to a non-magnetic clad material member used as a color material for a particle accelerator.

[0002]

2. Description of the Related Art A particle accelerator has a beam pipe for passing a particle beam of electrons or protons in a main ring, and an electromagnet is used to efficiently orbit the charged particles around the beam pipe. Is provided. In particular, with the recent increase in energy of particle accelerators, high-field superconducting electromagnets are becoming indispensable. Therefore, the superconducting electromagnet uses a coil winding method called a double-shell structure for the superconducting coil, but a supporting structure member commonly called a collar is required to support a strong electromagnetic force applied to the coil. Usually, this collar has a two-dimensionally complicated shape in conformity with the shape of the superconducting coil, so it has been attempted to manufacture a plate made of a nonmagnetic material and having a thickness of about 1 mm by press punching.

This color material is non-magnetic and requires sufficient strength. From this point of view, the stainless steel material was applicable, but with such a material, the ultra-low temperature of liquid helium temperature (4.2K) necessary for superconducting the coil body (Nb · Ti / Cu) was achieved. There is a problem in that it does not match the shrinkage ratio that occurs when cooled, and the supporting rigidity given during fabrication at room temperature decreases during use at extremely low temperatures.

[0004]

As described above, the collar material in the particle accelerator must support the strong electromagnetic force applied to the superconducting electromagnet. In other words, one of the most important items in the mechanical design and manufacture of superconducting electromagnets is the improvement of the magnet support rigidity. For that purpose, the coil body should be structured so that it is always properly supported and assembled at room temperature. The obtained electromagnet support rigidity must be maintained even in a cryogenic state.

The present invention satisfies the above-mentioned current requirements, and optimizes the mechanical strength, rigidity, and heat shrinkage amount by laminating and integrating different kinds of nonmagnetic materials having different heat shrinkage amounts. It is an object of the present invention to provide an improved clad material for an electromagnetic structure, particularly a collar material for supporting a superconducting electromagnet in a particle accelerator.

[0006]

In order to achieve the above-mentioned object, the gist of the present invention is to: (1) laminate non-magnetic steel on both sides or one side of an Al material by metal-to-metal joining to obtain tensile strength It is 50 kgf / mm ² or more, a Young's modulus 10000 kgf / mm ²
Above, the relative magnetic permeability is 1.002 or less, and at room temperature 4
A clad material for electromagnetic structure having a heat shrinkage ratio of 0.33% or less when cooled to K. (2) The clad material is up to 2% Mn by weight and 1.5% up to M
Al material containing at least one of g, and C on the both sides or one side of which is 0.12% or less by weight%, 1.00%
The following Si, 8.00 to 12.00% Mn, 5.00
~ 7.00% Ni, 18.0 ~ 21.00% Cr
And non-magnetic steel containing
It is preferable that the plate thickness ratio of the non-magnetic steel: Al material is 0.3 to 2.5, and the laminated plate thickness of both materials at this time is 0.5 to 5 mm, (3) The Al material described in the above items and non-magnetic steel are laminated, and hot rolling is performed at a temperature of 500 ° C. or less at a reduction ratio of the Al material of 30 to 60% to obtain a plate thickness of 0.5 to
This is a method for producing a clad material for electromagnetic structure having a plate thickness ratio of 5 mm and a non-magnetic steel: Al material of 0.3 to 2.5.

The above-mentioned material of the present invention has good workability and can be widely used as a structural material for low-temperature equipment which requires adjustment and optimization of heat shrinkage and the like, and is particularly suitable for a collar for supporting a superconducting electromagnet of a particle accelerator. is there.

The present invention will be described in detail below. The Al material constituting the clad material of the present invention includes, for example, the characteristics required when used as a support material for a superconducting electromagnet of a particle accelerator, in consideration of the relationship with a non-magnetic steel as a composite material. You have to choose. One of the characteristics that must be possessed is that the relative permeability is small in order not to disturb the magnetic field accuracy. Pure Al is suitable in this sense, but its strength is insufficient. Therefore, in the present invention, it is recommended to use an Al alloy material containing one or both of Mn 2.0% or less and Mg 1.5% or less. Mn dissolves in the Al matrix and improves corrosion resistance. Therefore, Mn can be added up to 2.0%, but the effect is saturated if it is added more. Mg is added to increase the strength, but if it is contained in an excessively large amount, cold workability deteriorates,
Further, it is preferably 1.5% or less because it accelerates the formation of the surface oxide film and lowers the bonding property. In addition, this kind of A
The l-alloy is specified in JIS A3004-O.

The non-magnetic steel used as a laminating material is required to have a high strength and a non-magnetic property at an extremely low temperature, and a preferable component composition is C: 0.12% or less by weight% and S
i: 1.00% or less, Mn: 8.00 to 12.00%,
Ni: 5.00 to 7.00%, Cr: 18.0 to 2
It is an alloy steel containing 1.00% and the balance substantially Fe. 80kgf / mm ² for alloy steel with such composition
The above tensile strength and relative permeability at 4.2K 1.00
A value of 2 or less is obtained. As the seed alloy steel, YUS (registered trademark) 130S which is already on the market can be used.

In the present invention, the above Al material is used as a base material, and non-magnetic steel is laminated on one surface or both surfaces thereof as a laminated material to form a clad material. The obtained clad material is required to have the following characteristics, for example, for a color material used at an ultralow temperature. That is, the proof stress at room temperature (σ _0.2 ) ≧ 3 in order to apply stress in advance at the time of fabrication at room temperature.
By setting 0 f / mm ² , tensile strength (TS) ≧ 50 kgf / mm ² , and Young's modulus (E) ≧ 10000 f / mm ² , it is possible to support a superconducting coil that generates a strong electromagnetic force at extremely low temperatures. Also, from room temperature to such extremely low temperature (4K
In order to synchronize with the heat shrinkage of the superconducting coil generated by cooling to (near), the heat shrinkage is 0.33% or less, and the relative permeability (μ) at the same temperature is 1.002.
It should be as follows. Furthermore, excellent workability is required so that burrs do not appear during molding.

In order to obtain the above-mentioned characteristics, it is determined by the characteristics and the lamination ratio of the Al material and the non-magnetic steel, which is important especially for specifying the shrinkage rate of the clad material at extremely low temperatures. As described above, in order to bring the superconducting coil made of Nb-Ti / Cu into a superconducting state, the contraction rate that occurs when cooled to about 4K with liquid helium from room temperature is theoretically 0.33% or less of Cu. Therefore, practically, it is in the range of 0.28% or more from the limit of the Cu ratio for maintaining the superconducting state stably. On the other hand, in the same situation, the shrinkage rate of non-magnetic steel is approximately 0.26%, which is as high as 0.4% in the Al material, and there is a large difference in the shrinkage rate that occurs at extremely low temperatures for both materials. Therefore, simply laminating and joining both metals with different characteristics like this,
It does not match the contraction rate of the superconducting coil, and it becomes difficult to reliably support the superconducting coil at a predetermined position in the extremely low temperature range.
Eventually, the magnetic field will be disturbed. Regarding the clad material obtained by laminating and joining the non-magnetic steel to the Al material, the present inventors have found that the thickness ratio (laminating ratio) of the non-magnetic steel to the Al material is related to the heat shrinkage ratio that occurs in the extremely low temperature range (4K). Upon examination, a solid line as shown in FIG. 1 was obtained. That is, as is apparent from this figure, by adjusting the stacking (cladding) ratio within the range of 0.3 to 2.5, the heat shrinkage ratio of the practical Nb-Ti / Cu coil becomes approximately equal to the range. As a result, it was found that it is extremely suitable as a color material for particle accelerators.

Further, in order to use such a clad material as a collar material for a particle accelerator, a plurality of collar materials processed into a shape having a hole for inserting a superconducting electromagnet in the central portion are spot-welded and joined. At the same time, the superconducting electromagnet is supported in parallel in the length direction of the beam pipe.

In order to manufacture the clad material, there are methods of adhering with an organic resin or joining by explosive bonding, but in the former case, it is difficult for the adhesive material to withstand a low temperature of 4K, and in the latter case. Bonding (explosion welding) is performed at the slab stage, and the hot rolling performed to form the plate material thereafter and the annealing (strain relief) after cold rolling are performed at a temperature equal to or higher than the melting point of Al. It becomes difficult to reliably obtain the excellent clad material of. Therefore, in the present invention, the rolling method, that is, the strip-shaped non-magnetic steel and Al are heated to 500 ° C. or lower and overlapped, regardless of the method such as adhesion or explosive adhesion, and the reduction ratio of Al in the atmosphere is about 30% or more. It can be obtained by rolling at a reduction rate. By carrying out the rolling at a rolling reduction of 30% or more, the bonding strength becomes large and peeling does not occur even in an extremely low temperature range. However, if the rolling reduction exceeds 60%, the non-magnetic steel will also be rolled down. Therefore, strain relief annealing at 700 ° C or higher for this is required, and therefore, the treatment above the melting point of Al is required, so that the interface Alloying occurs and the characteristics deteriorate.

Further, when the clad material is manufactured by this method, if the plate thickness is 0.5 mm or more, stable rolling is possible. On the other hand, when the final shape is punched, the plate thickness is 5 mm. Must be:

[0015]

EXAMPLES Examples of the present invention will be described below. As weight%, Cu: 0.13%, Si: 0.19%, Fe:
0.48%, Mn: 10.5%, Mg: 0.93%, Z
n: 0.01%, balance Al material consisting essentially of Al (J
IS30004) on both sides, as a weight%, C: 0.0
7%, Si: 0.6%, Mn: 1.05%, P: 0.0
24%, S: 0.001%, Ni: 5.98%, Cr:
Non-magnetic steel (YUS130S) consisting of 19.26%, N: 0.32% and the balance being substantially Fe is laminated, heated to 450 ° C., and rolled at a rolling reduction of 45% of an Al material to obtain a plate thickness of 2.5 mm. The metal-clad clad material was manufactured. At this time, the lamination ratio of the products, that is, the nonmagnetic steel / Al material was 1.27 (nonmagnetic steel-Al material-nonmagnetic steel = 0.7-1.1-0.7 mm).

Table 1 shows the characteristics of the obtained clad material. The characteristics of the Al material and the non-magnetic steel are also shown in the table.

[0017]

[Table 1]

As is clear from the above table, by setting the clad material lamination ratio to 1.27, a clad material having the desired mechanical properties can be obtained, and the shrinkage ratio which occurs at an extremely low temperature of 4K also shows a cross section. It is possible to tune the shrinkage rate of the superconducting coil of 0.29 in the area ratio of Nb: Ti: Cu to 1: 1: 1.6, and the superconducting electromagnet support rigidity due to the stress given in advance at room temperature is extremely high. It can be held even when excited at low temperature.

It is to be noted that SUS304 and 31 have mechanical properties close to those of the non-magnetic steel constituting the clad material of the present invention.
There are 6 materials, but these have poor magnetic properties at low temperatures (relative permeability of 1.01 or more), which affects magnetic field accuracy.

[0020]

As described above, the non-magnetic steel / Al of the present invention is used.
The clad material can adjust the heat shrinkage at cryogenic temperature by adjusting the composition thickness ratio to an appropriate level, and is particularly suitable for a long color material for particle accelerators. It is a great benefit to improve the performance by increasing the magnetic field.

[Brief description of drawings]

FIG. 1 is a diagram showing a relationship between a lamination (cladding) ratio and a heat shrinkage rate.

[Procedure amendment]

[Submission date] March 12, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0017

[Correction method] Change

[Correction content]

[0017]

[Table 1]

Claims (5)

[Claims] 1. A non-magnetic steel on either side or both sides of the Al material is laminated and integrated by bonding between the metal, the tensile strength of 50 kgf / mm ² or more, a Young's modulus 10000 kgf / mm ² or more, relative permeability 1.0
A clad material for an electromagnetic structure, which has a property of not more than 02 and a heat shrinkage ratio of not more than 0.33% generated when cooled from room temperature to 4K. 2. An Al material containing at least 2% by weight of Mn and at least 1.5% of Mg at least on one side and 0.1% or less by weight% of C, 1. 0
0% or less of Si, 8.00 to 12.00% of Mn, 5.
A nonmagnetic steel containing Ni of 0.000 to 7.00% and nonmagnetic steel of 18.0 to 21.00% of Cr is metal-metal bonded to be laminated and integrated, and the plate thickness ratio of the nonmagnetic steel: Al material is set to 0. The clad material for electromagnetic structure according to claim 1, wherein the clad material is 3 to 2.5. 3. The clad material for electromagnetic structure according to claim 2, wherein the laminated plate thickness is 0.5 to 5 mm. 4. A collar for supporting a superconducting electromagnet in a particle accelerator, which is suitable for processing the clad material according to each of the above claims and using it at cryogenic temperatures. 5. An Al material containing at least one of Mn up to 2% by weight and Mg up to 1.5% on both sides or one side, with C of less than 0.12% by weight and 1.00%. The following Si, 8.00 to 12.00% Mn, 5.00
Non-magnetic steel containing 7.00% Ni and 18.0 to 21.00% Cr is laminated and Al at a temperature of 500 ° C. or lower.
Hot rolling with a rolling reduction of 30% or more and 60% or less,
The plate thickness is 0.5 to 5 mm, and the plate thickness ratio of non-magnetic steel: Al material is 0.
A method for manufacturing a clad material for an electromagnetic structure, characterized in that it is 3 to 2.5.