JPH04190673A - Damper for superconducting rotor - Google Patents

Abstract

PURPOSE:To increase the joining area ratio and joining strength between joined members so as to improve the dimensional accuracy by joining a conductive member to a reinforcing member and reinforcing members to each other in solid-phase states and joining the reinforcing members to both end sections of the conductive member. CONSTITUTION:An intermediate Cu sleeve 11 is metallurgically joined to an outer SUS cylinder 12 and inner SUS cylinder 13 made of austenitic nonmagnetic steel by applying an isotropic pressure to the external surfaces of the cylinders 12 and 13 under a hightemperature condition. Then inner rings 14a and 14b made of austenitic nonmagnetic steel are joined to both ends of the sleeve 11 by applying an isotropic pressure under a high-temperature condition. Therefore, a low- and high-temperature damper which has a large joining area ratio, high joining strength, and high dimensional accuracy at its joined section is obtained and the vibration of the rotor of a superconducting generator can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a low-temperature damper and a room-temperature damper for a superconducting rotor used in a superconducting generator and a superconducting motor.

[Conventional technology]

FIG. 12 shows a cross-sectional structural diagram of the superconducting rotor.

The superconducting rotor includes a winding shaft 2 connected to a torque tube 1, a superconducting field winding 3 housed inside the winding shaft 2, a low-temperature damper 4 provided outside the winding shaft 2, and a room-temperature damper provided outside the winding shaft 2. Damper 5 and shafts 6.7 at both ends thereof
And a refrigerant supply bag for liquid helium, liquid nitrogen, etc.! It consists of 8th grade. The low-temperature damper 4 is used to shield radiant heat that enters from the room-temperature damper 5 side during operation, and to shield low-frequency magnetic flux that also enters from the stator side in the event of an accident in the power system. The room temperature damper 5 is for shielding high frequency magnetic flux.

Therefore, a metal with good conductivity is used as a material for the conductive members of the low-temperature damper 4 and the room-temperature damper 5.

Further, when shielding magnetic flux, a highly conductive metal generates electromagnetic force and deforms the conductive member, so it is necessary to bond a high-strength nonmagnetic metal as a reinforcing member to prevent this deformation. For this reason, the low-temperature damper 4 and the room-temperature damper 5 usually have a multilayer cylindrical structure having two or more layers. As a manufacturing method for a three-layer cylindrical structure having a structure in which a conductive metal is arranged in the middle layer and high-strength non-magnetic steel is arranged in the upper and lower layers, a conventional method for manufacturing a three-layer cylindrical structure is as shown in Japanese Patent Application Laid-Open No. 55-8265. A method of manufacturing a three-layer cylindrical structure by shrink fitting is known. Alternatively, a method is known in which a three-layer cylindrical structure is manufactured by joining cylindrical bodies together by an explosive pressure welding method using explosives.

[Problem to be solved by the invention]

However, in the former shrink-fit method, the contact surfaces of the three cylindrical layers are not metallurgically joined, so centrifugal force and electromagnetic force are superimposed, as in the low-temperature damper 4 and room-temperature damper 5 for superconducting rotors. However, there is a concern that a gap may be created between the inner and outer cylindrical bodies made of non-magnetic high-strength metal and the intermediate cylindrical body made of conductive metal, and the effect of reinforcement from the inside and outside is weak. There is. In addition, when producing the same three-layer cylindrical body using the latter explosive welding method, the contact surfaces of each cylindrical body are almost metallurgically joined, so that when centrifugal force and electromagnetic force are applied during use, the mechanical Although it has the advantage of high mechanical strength, it is difficult to apply pressure evenly when explosively welding the three-layer cylindrical body, so large deformations such as bending and buckling of the cylindrical body tend to occur. In addition, due to the uneven blast pressure distribution, the roundness and straightness of the joint interface of the three-layer cylinder deteriorate, and the density difference between the non-magnetic high-strength metal for the reinforcing member and the conductive metal for the conductive member causes superconductivity. This has the disadvantage that it causes imbalance when the rotor rotates, causing vibration. Furthermore, during explosive pressure welding, non-bonded areas tend to occur at the detonation point and other locations, resulting in a low bonding rate of 90% or less. Furthermore, in the case of the explosive welding method, there is a problem in that when materials including welded parts are explosively welded, non-bond parts are likely to occur in the welded parts.

An object of the present invention is to provide a manufacturing method for a low-temperature damper and a room-temperature damper for a rotor of a superconducting generator having a composite structure including two or more bonding members, which has a high bonding area ratio and bonding strength of the bonding members, and has good dimensional accuracy. It is about providing.

Another object of the present invention is to provide a low-temperature damper and a room-temperature damper for a rotor of a superconducting generator that can avoid dissimilar metal welding in a structure where both ends of the damper and the room-temperature damper need to be welded to another member of the rotor. The purpose is to provide the structure number of the damper.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a superconducting rotor damper having a composite structure in which a conductive member forms an intermediate layer of a three-layer cylindrical structure, and a reinforcing member forms an upper layer and a lower layer of a three-layer cylindrical structure. The conductive member and the reinforcing member are joined together, and the reinforcing members are joined together by solid phase welding by hot isostatic pressing, and the reinforcing member is joined to both ends of the conductive member. This is a damper for superconducting rotors.

In the damper, the conductive member is preferably made of copper or a copper alloy, and the reinforcing member is preferably made of austenitic nonmagnetic steel. In addition, it is preferable that the conductive member contains 99.9% or more of copper by weight, with the remainder consisting of impurities such as Fe, and the austenitic nonmagnetic steel of the reinforcing member contains 0.01 to 0.01% by weight of nitrogen. 0.40%, 15-28% Cr, Ni
8 to 15%, C 0.03% or less, and Mn 2% or less.

Contains 2% or less of Si, 0.5 to 3.0% of Mo, and the balance is F.
Preferably, it consists of e and unavoidable impurities.

In addition, the austenitic nonmagnetic steel of the reinforcing member contains 0.01 to 0.40% nitrogen, 15 to 28% Cr, and N
The austenitic nonmagnetic steel of the reinforcing member should contain 8 to 15% of i, 0.03% or less of C, 2% or less of Mn, and 2% or less of Si, with the balance consisting of Fe and unavoidable impurities. In weight percent, C is 0.08% or less, Si is 1% or less, Mn is 2% or less, Ni is 24-27%, and Cr is 13%.
~16%, Mo 1.0-1.5%, Ti 1.5-2
．． 4%, ■0.1-0.5%, AQ 0°1-0.4
%, with the remainder consisting of Fe and unavoidable impurities. Also, the copper alloy of the conductive member should contain Cr from 0.2 to 0.2% by weight.
1.0%, Zr o.

It is preferable that the copper alloy of the conductive member contains 05 to 0.3% of N, with the remainder consisting of Cu and unavoidable impurities.
i 1.2~2.8%, Si 0°3~0.7%, Zr
It is preferable to contain Ti-0.1 to 1.0%, with the remainder consisting of Cu and unavoidable impurities.

In addition, when each member of the composite structure is solid-phase joined by hot isostatic pressing, the surface roughness of the joint surface between the conductive member and the reinforcing member is set to 2 μm or less in terms of center line average roughness Ra. The surface roughness of the joint surfaces between the reinforcing members is the center line average roughness R
Formed to a thickness of 0.5 μm or less at a temperature of 750°C or higher,
It is preferable that the bonding be performed by hot isostatic pressing (HIP) at a pressure of 10 MPa or more and a temperature and pressure holding time of 60 sin or more. In addition, when joining each member of the composite structure by hot isostatic pressing, a thickness of 30 μm of Fe, Ni or Ni alloy, etc. is used to increase the bonding strength between each member.
It is preferable that one or more types of intermediate materials of m or less are interposed.

In addition, it is preferable that the conductive member of the composite structure has a roundness of 99.9% or more, a straightness of 99°95% or more, and a wall thickness uniformity of 99% or more. When joining members by hot isostatic pressing, it is preferable to join them under the hydrostatic pressure of an inert gas or a reducing gas.

That is, in order to achieve the above objective, hot isostatic pressure is applied to the outer surfaces of the inner and outer cylinders made of austenitic non-magnetic steel, and the intermediate cylinder made of copper or copper alloy and the cylinder made of austenitic non-magnetic steel are The contact surface with the body is metallurgically bonded. Furthermore, by providing an austenitic non-magnetic steel cylinder at both ends of a copper or copper alloy cylinder and joining them using hot isostatic pressure, parts such as torque tubes and shafts can be attached to low-temperature dampers and room-temperature parts. This is to avoid welding different materials when welding the damper. Therefore, the low-temperature damper and room-temperature damper of the present invention have a structure in which austenitic nonmagnetic steel, copper or a copper alloy, and austenitic nonmagnetic steel are joined together by hot isostatic pressing (HIP). When joining austenitic nonmagnetic steels together, if the surface roughness of the joint surfaces is rough, the joint strength of the joint tends to be low. In this case, in order to increase the bonding force of the bonding surfaces, the bonding is performed with an intermediate material such as Fe, Ni, or Ni alloy interposed therebetween. The maximum thickness of this intermediate material is preferably 30 μm or less from the viewpoint of diffusion.In addition, hot isostatic pressing is used to reduce the deformation of the low-temperature damper after pressurization, so it is inert. Equivalent pressurization using gas or the hydrostatic pressure of a reducing gas is preferable.

By the above method, a low-temperature damper and a room-temperature damper with high bonding area ratio and bonding strength of the bonded portions and good dimensional accuracy can be obtained, and vibrations during rotation of the superconducting generator rotor can be prevented. Furthermore, when joining other parts such as the torque tube and shaft, problems such as weld cracks can be prevented since dissimilar metal welding is avoided.

[Effect]

The present invention requires the joint area ratio and joint strength of the joint part and the dimensional accuracy of the joint parts when manufacturing a composite structure cylindrical body used for a rotating body such as a low-temperature damper for a superconducting rotor and a room-temperature damper. Therefore, as a manufacturing method, the joint parts are heated to a high temperature while applying pressure to bring the joint parts into close contact, and at the same time, the distance between the metals of the relative members at the joint surface is brought close to the distance where atomic attraction acts, This method uses a hot isostatic pressing method (hereinafter referred to as HIP) that causes thermal diffusion between relative metals. The surface to be joined by HIP has low surface roughness,
It is also desirable to have a material with less oxides and impurities.Therefore, it is necessary to reduce the surface roughness of the surface requiring bonding, keep it clean, and further evacuate the interior of the three-layer internal body to degas it. It is expected that the bonding strength of the bonding surfaces will increase as the bonding surfaces are cleaned.

HIP bonding conditions include conditions such as bonding temperature, bonding time, pressing force, and surface roughness, and it is necessary to select appropriate conditions depending on the materials to be bonded.

For this reason, conditions suitable for HIP bonding were investigated through diffusion bonding experiments described below.

Table 1 shows the chemical compositions of austenitic nonmagnetic steel 5US316LN (hereinafter referred to as SUS) and oxygen-free copper (hereinafter referred to as Cu) used to examine HIP bonding conditions. In addition, when Cu alloy is used instead of Cu and 5U
Similar results can be expected when other non-magnetic steels such as 5US304LN are used instead of S316LN.

The diffusion test was conducted by applying pressure to SUS and SUS or Cu from the top side. Diffusion bonding uses uniaxial pressure, and there is a risk that the specimen will be crushed and deformed, so a heat-resistant alloy (All
oy 800) was provided. The degree of vacuum during bonding is 1
0-”Pa.The shape of the test piece was 8 mm in diameter and 1 in length.
It was set to 0wn. The bonding temperature was 850 to 1070 degrees, the pressure was 10 to 150 MPa, and the bonding time was 60 and 18
It was set to 0+*in.

The surface roughness of the bonded surface was machined to a center line average roughness Pa of 0.8 μm, and then polished using water-resistant emery paper #800-80, with Ra ranging from 0.06 to 1°95 μm. After diffusion bonding, the plate tensile test piece taken had a parallel length of 5 m, a radius of 21111, and a thickness of 3 m. The test piece was taken so that the boundary of the joint was at the center of the parallel part. The tensile test was performed using an Instron type tensile tester (5 ton capacity).
The tensile strength was measured at IIIIII/min.

The test temperature was room temperature (10-15℃), and the gauge distance was 4mm.
And so.

FIG. 6 shows the influence of temperature on the bonding strength of SUS/Cu by diffusion bonding. The bonding conditions were a bonding time of 60 min, and a pressure of 10 and 50 MPa. The bonding strength in the range of 850 to 1030°C is approximately 190 MPa, but the bonding strength tends to decrease slightly at a bonding temperature of 1030°C or higher. All of the fracture positions of the bonded test pieces were on the Cu base metal side, and the bondability was good. Although not shown in Fig. 6, similar results can be obtained even if the junction temperature is 750°C, and therefore the H of SUS/Cu
If the IP temperature is 750° C. or higher, sufficient bonding strength can be ensured.

Ni and Fe at SUS/Cu junction interface
The change in concentration was measured. The bonding conditions are a bonding temperature of 1030℃.
℃, and the bonding time was 60 min.

Ni and Fe rapidly decrease at the joint as they move from the SUS side to the Cu side, but Ni and Fe decrease near the joint boundary.
A slight diffusion of is observed. It is thought that the vicinity of the joint is strengthened by solid solution due to the diffusion of Ni, Fe, etc.

Figures 7(a) to (Q) show Cu with the receiver in place to investigate the state of atomic diffusion from the SUS side to the Cu side.
)), junction temperature 1030°C ((b) in the same figure) and 107°C
The EDX measurement results of the Cu portion of the bonded test piece at 0° C. ((C) in the same figure) are shown. The measurement position of the bonded specimen is C from the bonding boundary.
It is 0.25 kaku to the u side. However, only Cu was detected in the test piece with the receiver in place and the bonding temperature of 1030°C.

Cr and Fe were detected in the test piece with a bonding temperature of 1070°C. When Cr and Fe diffuse to the Cu side and Cu is alloyed, the electrical resistance of Cu increases, so SUS/Cu
The HIP temperature is preferably 1070°C or less.

Figure 8 shows the effect of bonding temperature on SUS/SUS bonding characteristics.The bonding conditions are a bonding time of 60 sin;
The pressing force is 50 MPa. The bonding strength shows a higher value as the bonding temperature rises, and when the bonding temperature is 1000° C. or higher, a strength equivalent to that of the SO8 base material is obtained. Therefore, the HIP temperature of SUS/SUS is preferably 1000"C or higher. If the bonding temperature is 1050℃, the bonded test piece will break on the SUS base material side, but the bonding temperature will be 1000℃ to 1030℃.
There are cases where the base material breaks and cases where the joint breaks.
This causes variations in the fracture position. This is thought to be caused by the surface roughness of the joint surface of the test piece, as described below.

Figure 9 shows the influence of surface roughness on SUS/SUS bonding characteristics. The bonding conditions were a bonding temperature of 1050°C, a bonding time of 180 min, and a pressure of 100 MPa.
It is. Bonding strength and elongation increase as the surface roughness decreases, and when the surface roughness is less than 0.5 μm, the fracture location of the bonded specimen is the base metal fracture, and surface roughness is an important factor in increasing bonding strength. That's what I found out. Therefore S
The US surface roughness is preferably 0.5 μm or less.

FIG. 10 shows the influence of bonding temperature on the SUS/SUS bonding characteristics using a test piece with a surface roughness of 0.06 μm on the bonding surface. It was found that the bonding strength in the bonding temperature range of 985°C to 1050°C is equivalent to that of the SUS base material, but when the bonding temperature is 1030°C or higher, the fracture position becomes the base metal. Therefore.

When HIP-bonding SUS/SUS materials, more preferable joining performance can be obtained by setting the surface roughness of the SUS materials to 0.06 μm and setting the HIP temperature to 1030° C. or higher.

Figure 11 shows SUS/
The influence of pressurizing force on the bonding properties of SUS is shown. The bonding conditions are a bonding temperature of 1050°C and a bonding time of 180 min.
It is. The bonding strength in the range of 50 to 150 MPa is equivalent to that of the SUS base material, but when the pressure is 50 MPa,
In the case of a, the specimen broke at the joint, and the elongation showed a small value. On the other hand, when the applied force exceeds 100 MPa, the base material breaks, and it was found that the applied force also contributes to the bonding properties of SUS/SUS. Therefore, SUS/SUS is HI
In the case of P-joining, a pressure equal to or greater than 50 MPa can provide a bonding strength equivalent to that of the base metal, but in order to make the bonding properties stronger, the pressure is preferably greater than or equal to 100 MPa.

To summarize the results of the above diffusion bonding experiments, HIP
/To bond SUS and SUS/Cu at the same time, the bonding temperature should be 1000℃ or higher and the surface roughness Ra should be 0.5μ.
m or less, and the pressing force needs to be 50 MPa or more. The time for maintaining the bonding temperature and pressure is preferably 60 min or more.

In addition, to bond SUS/Cu together using HIP, the bonding temperature must be 750°C or higher, the bonding time must be 60 min or more,
It is preferable that the pressing force be 10 MPa or more and the surface roughness Ra be 2 μm or less.

〔Example〕

A bunch of lost seeds Example 1 of the present invention will be described below.

HIP using the test materials shown in Table 2 under the conditions shown in Table 3.
Welded. The dimensions of the test piece for HIP bonding were 32 cm in diameter and 22 cm in length. The test piece was sealed in a carbon steel capsule, heated to 400°C, degassed and sealed, and then HIP bonded. After HIP bonding, precipitation strengthened specimen material (second
2. &3 and &7) were subjected to aging treatment.

Next, a resistivity test piece with dimensions of 2×2×30 m was taken as a tensile test piece, and its properties were measured.

Table 4 shows the characteristics of each bonded test piece. Note that the specific resistance is a characteristic of the conductive member. The fracture position of the tensile test piece was on the base metal side, and good bonding properties were obtained.

According to this embodiment, when the conductive member is copper and the reinforcing member is austenitic nonmagnetic steel, when the conductive member is a copper alloy and the reinforcing member is austenitic nonmagnetic steel, and when the reinforcing member is made of austenitic nonmagnetic steel, Good bonding strength and conductivity can be obtained in any case, such as when bonding.

Table 3 Table 4 [Example 2] As Example 2 of the present invention, the conductive member had Cu purity of 99.9%.
A low-temperature damper made of the above oxygen-free copper and whose reinforcing member is made of 5US316LN with an N content of 0.12% or more will be described. Note that the same effect can be obtained by using 5US304LN as the reinforcing member.

FIG. 1 shows a configuration diagram of a low-temperature damper according to this embodiment. The main body of the low-temperature damper according to this embodiment is made of Cu sleeve 11 and SUS.
Outer cylinder 12, SUS inner cylinder 13, SUS inner cylinder 14a
Consists of 4b. The Cu sleeve 11 is a conductive member of the low-temperature damper, and the SUS outer cylinder 12, the SUS inner cylinder 13, and the SUS
The US middle ring 14a4b is the reinforcing member. FIG. 2 is a partial cross-sectional view showing the structure for attaching the low-temperature damper to the torque tube 1. The torque tube 1 is provided with a protrusion 15 at the attachment part of the low-temperature damper, and welded 16 at that part. The reinforcing members 14a and 14b are designed to prevent them from peeling off due to thermal stress during welding.

This makes it possible to weld similar materials so that copper does not get mixed into the welded area. The protrusion 15 is provided for joining to the torque tube and is also provided to enable rejoining.

FIG. 3 shows the manufacturing process of this example, and FIG. 4 shows a schematic diagram of the HIP apparatus used in the manufacturing.

The HIP device connects the Cu sleeve 11 to the SUS outer cylinder 12 and SU
S inner cylinder 3. and SUS medium reshi ring 14a4b, and SUS medium reshi ring 14a4b to SUS medium reshi ring 14a4b.
It was used to join the US outer cylinder 12 and the SUS inner cylinder 13.

In this example, the outer diameter of the SUS outer cylinder 12 is 546 m, the length of the Cu sleeve 11 is 860 mm, the wall thickness of the SUS outer cylinder 12 and the SUS inner cylinder 13 is 7.5 m, and the Cu sleeve 11 is 7.5 m thick.
The wall thickness of the SUS medium reshi ring 14a4b was 6 mm. These dimensions are determined appropriately according to the capacity of the superconducting rotor, and the S at both ends of the Cu sleeve 11 does not affect the bonding characteristics of HIP bonding.
In the US Medium Reshiring 14a4b, both ends of the low temperature damper are S.
Must be welded with US torque tube.

This was installed to avoid SUS/Cu dissimilar metal welding at that time. SUS outer cylinder 12. SUS inner cylinder 13
And the surface roughness of Reshiring 14a4b in SUS is SU
The part to be joined to the S medium reshiring 14a4b was made to be 0.05 μm or less by puff polishing, and the part to be joined to the Cu sleeve 11 was made to be 1.6 μm or less by machining. S
US outer cylinder 12/Cu sleeve 11 and Cu sleeve 1
1/The gap between the inner diameter and outer diameter of the SUS inner cylinder 13 is approximately 0.
6m - An end ring was attached by welding next to the SUS medium ring 14a4b. Although the end ring is not necessary to construct the cold damper body, it is a necessary component to form the HIP joint connector empty vessel. Therefore HIP
After bonding, the end ring is cut away. The material of the end ring may be any material that does not cause weld cracks when welding with the SUS outer cylinder 12 and the SUS inner cylinder 13. Therefore, 5US
304 was used. A degassing pipe was attached to the end ring by welding. A degassing tube is a tube for evacuation.

Gas such as air inside the end ring, SUS outer cylinder 12, and SUS inner cylinder 13 can prevent HIP bonding.
Before P processing, it was heated and degassed through a degassing tube.

The HIP bonding conditions of this example are based on the diffusion bonding test results, bonding temperature: 1050℃±15℃, pressure crab 130MP.
a, temperature and pressure holding time = 4 h was adopted.

After HIP processing, S is inspected by ultrasonic flaw detection from the SUS outer cylinder side.
US medium recyling 14a4b and SUS outer cylinder 12 and S
Connection status with US inner cylinder 13 and Cu sleeve 11 and S
Although the state of connection between the US outer cylinder 12 and the SUS inner cylinder 13 was inspected, no unattached portions were inspected.

Table 5 shows the dimensional changes of the low temperature damper due to HIP of this example. Since HIP bonding uses isostatic pressure, one of its features is that there is little risk of uneven deformation of the bonded body. However, deformation occurs due to the effects of voids between the cylindrical parts, thermal expansion differences between different materials, and uneven temperature distribution during bonding, so we measured the dimensions of the low-temperature damper before and after HIP with a micrometer and calipers. I asked for the quantity. The amount of dimensional change of the low-temperature damper is that the outer diameter of the SUS outer cylinder is on the contraction side ()ico, 5 to 0.75 mm, the inner diameter of the SUS inner cylinder is 0.7 to 1.05 m + ■ on the expansion side (+), and the length (Q
) direction is on the contraction side (-), Q, 66 mm, so isostatic pressure is applied Comparing the difference in diameter, the cylindrical HIP has a diameter difference of 0.
While it is small at less than 5mm, in cylindrical explosion contact it is about 10++
It has been reported that a very thick deformation of +++++ occurs. Therefore, it is clear that the HIP method is more suitable than the cylindrical explosion welding method for low-temperature dampers that require dimensional accuracy such as roundness and straightness of the SUS/Cu joint surface.

Figure 5 shows SUS/Cu and SUS of the low temperature damper.
/ Shows the test piece sampling position at the SUS joint.

In addition, Table 6 shows the tensile test results. Table 5 shows the joint joint trial number. Measurement position 1a, c: end, b: center, Table 6 ■ and ■ are SUS/SUS, and ■ and ■ are SUS/SUS.
It is Cu. The bonding strength of SUS/SUS is approximately 685
~705 MPa, and the fracture position of the bonded test piece is on the base metal side. In addition, the room temperature and −19
The bonding strength at 6° C. is approximately 190 to 255 MPa, and the fracture position of the bonded test piece is also on the Cu base material side.

The low-temperature damper of this embodiment has the effect of producing a low-temperature damper with a higher bonding area ratio and less deformation than the conventional cylindrical explosion welding method.

Table 7 shows the fatigue test results for the SUS/Cu boundary and Cu base material of the low-temperature damper. did. It can be seen that the crack propagation rate at the SUS/Cu interface in HIP bonding is equivalent to that in the Cu base metal, indicating that it has good fatigue properties and is superior to explosion welding.

Tables 7 and 8 show that the SUS outer cylinder 2, the SUS inner cylinder 3, and the SUS inner cylinder 4ab are used to manufacture cylinders with an N content of 0.
The results of a tensile test of a welded part of 25% or more SUS welding material and Inconel welding material used to join explosion welding material are shown.The test piece used was a diameter of 5 mm and a parallel length of 25 BII. It was carried out at a temperature of 196°C. HIP
The 0.2% yield strength of the welded joint of the SUS welding material for use is equivalent to that of the base metal, and has excellent strength at low temperatures. It is also clear that superior strength can be obtained at lower temperatures than Inconel welding materials used for joining blast welding materials.

Table 8 Table 9 shows the electrical resistivity of the sample taken from the Cu part which is the conductive member of the low temperature damper.The measurement sample was 2X2X6.
The size of the intestine was 0.0 cm. The specific resistance of 77 is reduced to about 178 at room temperature, clearly indicating that better conductivity can be obtained when used at lower temperatures.

Table 9 The low-temperature damper of this embodiment has the effect of producing a low-temperature damper with a higher bonding rate and less deformation than the conventional cylindrical explosion welding method. In addition, it has excellent electromagnetic shielding performance due to its excellent conductivity at low temperatures.

〔Effect of the invention〕

According to the present invention, in a low-temperature damper and a room-temperature damper comprising a conductive member and a reinforcing member, each member is joined by solid-phase diffusion bonding using hot isostatic pressing, so that the dimensional accuracy after joining is improved. expensive. Therefore, it has excellent balance characteristics during rotation. Furthermore, there are no unbonded parts and the joints have excellent strength, so they have excellent mechanical reliability. Furthermore, since the reinforcing member can be joined to both ends of the conductive member, weld cracking caused by welding different materials can be prevented when welding the low-temperature damper and the room-temperature damper to other parts.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of the structure of a low-temperature damper according to the present invention, and FIG.
The figure is a cross-sectional view showing the mounting structure of the low-temperature damper on the torque tube, Figure 3 is a manufacturing process diagram of HIP, Figure 4 is a schematic diagram of the same device, and Figure 5 is the low-temperature damper SUS/Cu and 5tJS. Figure 6 is a diagram showing the effect of bonding temperature on the joint strength of SUS/Cu, and Figures 7 (a) to (C) are the effects of its components. Diagrams showing S U
Effect of bonding temperature on S/Cu bonding strength 9 Surface roughness, bonding temperature. A diagram showing the influence of pressurizing force, and FIG. 12 is a cross-sectional structural diagram of a superconducting rotor. 1...torque tube, 4...thermal damper, 5...
・Normal temperature damper, 11...Cu sleeve, 12...S
US outer cylinder, 13...SUS inner cylinder.

Claims (1)

[Claims] 1. In a superconducting rotor damper having a composite structure in which the conductive member forms the middle layer of a three-layer cylindrical structure and the reinforcing member forms the upper and lower layers of the three-layer cylindrical structure, the conductive member and A superconducting rotor characterized in that the reinforcing members and the reinforcing members are solid-phase joined by hot isostatic pressing, and the reinforcing members are joined to both ends of the conductive member. Damper for use. 2. The damper for a superconducting rotor according to claim 1, wherein the conductive member is made of copper or a copper alloy, and the reinforcing member is made of austenitic nonmagnetic steel. 3. In claim 1, the conductive member contains 99.9% by weight of copper.
1. A damper for a superconducting rotor, characterized in that the damper contains 9% or more and the remainder consists of impurities such as Fe. 4. In claim 1, the austenitic nonmagnetic steel of the reinforcing member contains 0.01 to 0.40% nitrogen, 15 to 28% Cr, 8 to 15% Ni, by weight.
A damper for a superconducting rotor, comprising 0.03% or less of C, 2% or less of Mn, 2% or less of Si, 0.5 to 3.0% of Mo, and the balance consisting of Fe and inevitable impurities. 5. In claim 1, the austenitic nonmagnetic steel of the reinforcing member contains 0.01 to 0.40% nitrogen, 15 to 28% Cr, 8 to 15% Ni by weight,
A damper for a superconducting rotor, characterized in that it contains 0.03% or less of C, 2% or less of Mn, and 2% or less of Si, with the remainder consisting of Fe and unavoidable impurities. 6. In claim 1, the austenitic non-magnetic steel of the reinforcing member contains 0.08% or less of C, 1% or less of Si, 2% or less of Mn, 24 to 27% of Ni, and 13 to 13% of Cr by weight.
16%, Mo 1.0-1.5%, Ti 1.5-2.
4%, V 0.1-0.5%, Al 0.1-0.4%
A damper for a superconducting rotor, characterized in that the remainder consists of Fe and unavoidable impurities. 7. In claim 1, the copper alloy of the conductive member has C by weight%.
A damper for a superconducting rotor, characterized in that it contains 0.2 to 1.0% of r, 0.005 to 0.3% of Zr, and the remainder consists of Cu and inevitable impurities. 8. In claim 1, the copper alloy of the conductive member contains N by weight%.
i 1.2-2.8%, Si 0.3-0.7%, Zr
A damper for a superconducting rotor, characterized in that the damper contains 0.1 to 1.0% of Cu, and the remainder consists of Cu and unavoidable impurities. 9. In claim 1, when each member of the composite structure is solid-phase joined by hot isostatic pressing, the surface roughness of the joint surface between the conductive member and the reinforcing member is determined by the center line average roughness Ra representation method. So 2μ
m or less, and the surface roughness of the bonding surfaces between the reinforcing members is formed to a center line average roughness Ra of 0.5 μm or less, and the temperature and pressure are maintained at 750°C or higher and the pressing force is 10 MPa or higher. Hot isostatic pressurization for 60 min or more (
A damper for a superconducting rotor, characterized in that it is joined by HIP). 10. In claim 1, when joining each member of the composite structure by hot isostatic pressing, an intermediate material having a thickness of 30 μm or less such as Fe, Ni or Ni alloy is used to increase the bonding strength between each member. A damper for a superconducting rotor, characterized in that one or more types of are interposed therein. 11. The superconductor according to claim 1, wherein the conductive member of the composite structure has a roundness of 99.9% or more, a straightness of 99.95% or more, and a wall thickness uniformity of 99% or more. Damper for rotor. 12. The superconductor according to claim 1, wherein each member of the composite structure is bonded by hot isostatic pressing under hydrostatic pressure of an inert gas or a reducing gas. Damper for rotor.