Austenite steel, and austenite steel casting using same

Patent metadata

Field	Value
Publication number	US-10415423-B2
Application number	US-201615349383-A
Country	US
Kind code	B2
Filing date	Nov 11, 2016
Priority date	Nov 11, 2015
Publication date	Sep 17, 2019
Grant date	Sep 17, 2019

Abstract

Provided herein are an austenite steel that satisfies desirable strength and desirable castability at the same time, and an austenite steel casting using same. The austenite steel according to an embodiment of the present invention contains Ni: 25 to 50%, Nb: 3.8 to 6.0%, Zr: 0.5% or less, B: 0.001 to 0.05%, Cr: 12 to 25%, Ti: 1.6% or less, Mo: 4.8% or less, and W: 5.2% or less in mass %, and the balance Fe and unavoidable impurities, wherein the parameter Ps represented by the following formula (1) satisfies Ps≤38,

Ps=8.3[Nb]−7.5[Ti]+2.4[Mo]+3.5[W]  formula (1),

where [Nb], [Ti], [Mo], and [W] represent the contents of Nb, Ti, Mo, and W, respectively, in mass %.

First claim

What is claimed is:

1. An austenite steel consisting of:
Ni in an amount of 25 to 50% by mass;
Nb in an amount of 3.8 to 6.0% by mass;
Zr in an amount of 0.5% or less by mass;
B in an amount of 0.001 to 0.05% by mass;
Cr in an amount of 12 to 25% by mass;
Ti in an amount of 1.6% or less by mass;
Mo in an amount of 4.8% or less by mass;
W in an amount of 5.2% or less by mass; and
Fe and unavoidable impurities in an amount of a remaining balance of the austenite steel,
wherein the austenite steel satisfies:
Ps≤38, and
Ps=8.3[Nb]−7.5[Ti]+2.4[Mo]+3.5[W]

where [Nb], [Ti], [Mo], and [W] represent mass % of Nb, Ti, Mo, and W, respectively.

2. An austenite steel consisting of:
Ni in an amount of 30 to 45% by mass;
Nb in an amount of 3.8 to 5.0% by mass;
B in an amount of 0.001 to 0.05% by mass;
Cr in an amount of 12 to 25% by mass;
Ti in an amount of 1.0% or less by mass;
Mo in an amount of 4.8% or less by mass; and
W in an amount of 5.2% or less by mass; and
Fe and unavoidable impurities in an amount of a remaining balance of the austenite steel,
wherein the austenite steel satisfies
27≤Ps≤38, and
Ps=8.3[Nb]−7.5[Ti]+2.4[Mo]+3.5[W]

where [Nb], [Ti], [Mo], and [W] represent mass % of Nb, Ti, Mo, and W, respectively.

3. An austenite steel consisting of:
Ni in an amount of 30 to 40% by mass;
Nb in an amount of 3.8 to 4.9% by mass;
B in an amount of 0.001 to 0.05% by mass;
Cr in an amount of 15 to 20% by mass;
Ti in an amount of 1.0% or less by mass;
Mo in an amount of 3.4% or less by mass;
W in an amount of 3.2% or less by mass; and
Fe and unavoidable impurities in an amount of a remaining balance of the austenite steel,
wherein the austenite steel satisfies:
27≤Ps≤38, and
Ps=8.3[Nb] −7.5[Ti]+2.4[Mo]+3.5[W],

where [Nb], [Ti], [Mo], and [W] represent mass % of Nb, Ti, Mo, and W, respectively.

4. A austenite steel casting formed from the austenite steel of claim 1 .

5. The austenite steel casting according to claim 4 , wherein the austenite steel casting has a thickness of 50 mm or more.

6. The austenite steel casting according to claim 4 , wherein the austenite steel casting weighs at least 1 ton.

7. The austenite steel casting according to claim 4 , wherein the austenite steel casting is a constituent member of a steam turbine for power generating plants.

8. The austenite steel casting according to claim 7 , wherein the constituent member is a turbine casing or a valve casing.

9. A austenite steel casting formed from the austenite steel of claim 2 .

10. The austenite steel casting according to claim 9 , wherein the austenite steel casting has a thickness of 50 mm or more.

11. The austenite steel casting according to claim 9 , wherein the austenite steel casting weighs at least 1 ton.

12. The austenite steel casting according to claim 9 , wherein the austenite steel casting is a constituent member of a steam turbine for power generating plants.

13. The austenite steel casting according to claim 12 , wherein the constituent member is a turbine casing or a valve casing.

14. A austenite steel casting formed from the austenite steel of claim 3 .

15. The austenite steel casting according to claim 14 , wherein the austenite steel casting has a thickness of 50 mm or more.

16. The austenite steel casting according to claim 14 , wherein the austenite steel casting weighs at least 1 ton.

17. The austenite steel casting according to claim 14 , wherein the austenite steel casting is a constituent member of a steam turbine for power generating plants.

18. The austenite steel casting according to claim 17 , wherein the constituent member is a turbine casing or a valve casing.

Assignees

• Mitsubishi Hitachi Power Sys
• Tokyo Inst Tech

Inventors

• Kamoshida Hironori
• Imano Shinya
• Takeyama Masao

Classifications

• F01K7/00

  Steam engine plants characterised by the use of specific types of engine (F01K3/02 takes precedence); Plants or engines characterised by their use of special steam systems, cycles or processes (reciprocating-piston engines using uniflow principle F01B17/04); Control means specially adapted for such systems, cycles or processes; Use of withdrawn or exhaust steam for feed-water heating · CPC title

• C22C38/54 Primary

  with boron · CPC title

• C22C38/50

  with titanium or zirconium · CPC title

• C22C38/48

  with niobium or tantalum · CPC title

• C22C38/44

  with molybdenum or tungsten · CPC title