Welded structure for use at very low temperatures

• US 4,529,669 A
• Filed: 09/15/1983
• Issued: 07/16/1985
• Est. Priority Date: 09/20/1982
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Mori, Takanobu
• Primary Examiner(s): Andrews, Melvyn J.
• Assistant Examiner(s): YEE, DEBORAH
• Application Number:
  US06/532,521
• Time in Patent Office: 670 Days
• Field of Search: 310/10, 310/52, 310/64, 310/61, 310/261, 428/683, 428/685, 75/124 B, 75/126 J, 148/127
• US Class Current: 428/683
• CPC Class Codes: B23K 35/3086 containing Ni or Mn
• CPC Class Codes: B32B 15/011 all layers being formed of iron alloys or steels
• CPC Class Codes: Y10S 505/812 Stock
• CPC Class Codes: Y10S 505/877 Rotary dynamoelectric type
• CPC Class Codes: Y10T 428/12965 Both containing 0.01-1.7% carbon [i.e., steel]
• CPC Class Codes: Y10T 428/12979 Containing more than 10% nonferrous elements [e.g., high alloy, stainless]

Abstract

A welded structure for use at very low temperatures having structural metallic members of austenitic stainless steel welded with a welding material of austenitic stainless steel. The oxygen content of the portion of the deposited metal where there is no dilution with the material of the structural metallic member is not greater than 0.06 wt %. The structural metallic members and the deposited metal have chemical compositions consisting essentially of 0.01 to 0.1 wt % of C, 0.05 to 1 wt % of Si, 1 to 10 wt % of Mn, 8 to 20 wt % of Ni, 16 to 22 wt % of Cr and the balance substantially Fe and have a fully austenite structure. The Ni equivalent of the deposited metal ranges between 17 and 22. The welded structure for use at very low temperatures can be used, for example, as the container for the magnet of a superconducting generator rotor.

Claims

1. A welded structure for use at very low temperatures of below -150°

C., said welded structure being a container housing a magnet of a superconducting generator rotor and having structural metallic members of austenitic stainless steel welded together with a deposited metal of austenitic stainless steel, wherein said structural metallic members have a chemical composition consisting essentially of 0.01 to 0.1 wt. % of C, 0.05 to 1 wt. % of Si, 1 to 10 wt. % of Mn, 8 to 20 wt. % of Ni, 16 to 22 wt. % of Cr and the balance substantially Fe and have a fully austenite structure; and

said deposited metal has a chemical composition consisting essentially of 0.01 to 0.1 wt. % of C, 0.05 to 1 wt. % of Si, 1 to 10 wt. % of Mn, 8 to 20 wt. % of Ni, 16 to 22 wt. % of Cr, not greater than 0.03 wt. % of P+S, not greater than 0.06 wt. % of oxygen, 0.005 to 0.5 wt. % of at least one of the elements selected from the group consisting of Al, Ti, Zr, Mg, Ca, Y and a rare earth element and the balance substantially Fe;

said deposited metal having a fully austenite structure.

3. A welded structure for use at very low temperatures according to claim 1, wherein the Ni equivalent of said deposited metal, determined by the following formula, ranges between 17 and 22 wt. %:

space="preserve" listing-type="equation">Ni equivalent=Ni(wt. %)+30×

C(wt. %)+20×

N(wt. %).

5. A welded structure for use at very low temperatures according to claim 1, wherein said container housing the magnet is comprised of an inner damper, vessel and a torque tube which are made of an austenitic stainless steel, and said magnet comprises a super-conducting magnetic field coil cooled by liquid helium which is accommodated between said vessel and said torque tube.

2. A welded structure for use at very low temperatures of below -150°

C., said welded structure being a container housing a magnet of a superconducting generator rotor and having structural metallic members of austenitic stainless steel welded together with a deposited metal of austenitic stainless steel, wherein said structural metallic members have a chemical composition consisting essentially of 0.01 to 0.1 wt. % of C, 0.05 to 1 wt. % of Si, 1 to 10 wt. % of Mn, 8 to 20 wt. % of Ni, 16 to 22 wt. % of Cr, at least one of 0.01 to 4 wt. % of Mo and 0.01 to 0.2 wt. % of N and the balance substantially Fe and have a fully austenite structure; and

said deposited metal has a chemical composition consisting essentially of 0.01 to 0.1 wt. % of C, 0.05 to 1 wt. % of Si, 1 to 10 wt. % of Mn, 8 to 20 wt. % of Ni, 16 to 22 wt. % of Cr, at least one of 0.01 to 4 wt. % of Mo and 0.01 to 0.2 wt. % of N, not greater than 0.03 wt. % of P+S, not greater than 0.06 wt. % of oxygen, 0.05 to 0.5 wt. % of at least one of the elements selected from the group consisting of Al, Ti, Zr, Mg, Ca, Y and a rare earth element and the balance substantially Fe and has a fully austenite structure.

4. A welded structure for use at very low temperatures according to claim 2, wherein the Ni equivalent of said deposited metal, determined by the following formula, ranges between 17 and 22 wt. %:

space="preserve" listing-type="equation">Ni equivalent=Ni(wt. %)+30×

C(wt %)+20×

N(wt %).

6. A welded structure for use at very low temperatures according to claim 2, wherein said container housing the magnet is comprised of an inner damper, vessel and a torque tube which are made of an austenitic stainless steel, and said magnet comprises a superconducting magnetic field coil cooled by liquid helium which is accommodated between said vessel and said torque tube.

7. An electric rotary machine having a superconducting rotor, wherein said superconducting rotor comprises a drive shaft having at an end thereof a flange portion, a hollow shaft confronting said drive shaft with a gap therebetween and having a flange portion, a torque tube connected between said flange portions, a magnetic field coil provided on an outer peripheral surface of said torque tube, a vessel surrounding said magnetic field coil, a coolant pool formed inside said torque tube, collant supply means for supplying a coolant to said coolant pool through said hollow shaft, a cylindrical inner damper provided so as to surround said vessel, a cylindrical outer damper disposed so as to surround said inner damper and connected between said flange portions, coolant discharge means for collecting said coolant from said coolant pool through said hollow shaft, and a power lead passing through said hollow shaft for supplying said magnetic field coil with electric power, and wherein said torque tube, said vessel and said inner damper are made of an austenitic stainless steel having a chemical composition consisting essentially of 0.01 to 0.1 wt. % of C, 0.05 to 1 wt. % of Si, 1 to 10 wt. % of Mn, 8 to 20 wt. % of Ni, 16 to 22 wt. % of Cr and the balance substantially Fe and having a fully austenite structure;

and said torque tube and said vessel and said torque tube and said inner damper are, respectively, welded together with a deposited metal of austenitic stainless steel having a chemical composition consisting essentially of 0.01 to 0.1 wt. % of C, 0.05 to 1 wt. % of Si, 1 to 10 wt. % of Mn, 8 to 20 wt. % of Ni, 16 to 22 wt. % of Cr, not greater than 0.03 wt. % of P+S, not greater than 0.06 wt. % of oxygen, 0.005 to 0.5 wt. % of at least one of the elements selected from the group consisting of Al, Ti, Zr, Mg, Ca, Y and a rare earth element and the balance substantially Fe;

said deposited metal having a fully austenite structure.