12Cr Alloy steel for a turbine rotor

• US 20030145916A1
• Filed: 10/25/2002
• Published: 08/07/2003
• Est. Priority Date: 10/25/2001
• Status: Abandoned Application

• Current Assignee: Mitsubishi Heavy Industries, Ltd.
• Original Assignee: Mitsubishi Heavy Industries, Ltd.
• Inventors: Saito, Masahiro, Takano, Yusaku, Fujita, Akitsugu, Kamada, Masatomo
• Application Number:
  US10/280,052
• Publication Number:
  US 20030145916A1
• Time in Patent Office: Days
• US Class Current: 148/542
• CPC Class Codes: C21D 1/18 Hardening C21D1/02 takes precedence; Quenching with or without subsequent tempering quenching devices C21D1/62
• CPC Class Codes: C21D 6/004 containing Cr and Ni
• CPC Class Codes: C22C 38/002 containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
• CPC Class Codes: C22C 38/008 containing tin
• CPC Class Codes: C22C 38/44 with molybdenum or tungsten
• CPC Class Codes: C22C 38/60 containing lead, selenium, tellurium, or antimony, or more than 0.04% by weight of sulfur

Abstract

A turbine rotor material, that has sufficient corrosion resistance and stress corrosion cracking resistance and appropriate strength and toughness in a good balance, and a manufacturing method thereof are provided. The turbine rotor material is a 12Cr alloy steel that contains: C of 0.01 to 0.10%, Si of 0.01 to 0.50%, Mn of 0.1 to 1.0%, Cr of 9 to 13%, Ni of 2 to 7%, Mo of 0.3 to 3%, N of 0.01 to 0.10%, all in weight percent, and remains of Fe and incidental impurities.

Claims

1. A 12Cr alloy steel for a turbine rotor, containing:

C of 0.01 to 0.10%, Si of 0.01 to 0.50%, Mn of 0.1 to 1.0%, Cr of 9 to 13%, Ni of 2 to 7%, Mo of 0.3 to 3%, N of 0.01 to 0.10%, all in weight percent, and remains of Fe and incidental impurities.

2. A 12Cr alloy steel for a turbine rotor as claimed in claim 1, further containing any one or more of rare earth elements of 0.003 to 0.03%, Ca of 0.001 to 0.009% and B of 0.0005 to 0.005%, all in weight percent.

3. A 12Cr alloy steel for a turbine rotor as claimed in claim 1 or 2, wherein a quantity of impurity elements of said incidental impurities is controlled so as to contain:

P of 0.0012% or less, S of 0.005% or less, Al of 0.015% or less, As of 0.008% or less, Sn of 0.008% of less and Sb of 0.005% or less, all in weight percent.

4. A 12Cr alloy steel for a turbine rotor as claimed in claim 1 or 2, wherein a Cr equivalent weight shown by “

[Cr %]+2[Si %]+1.5[Mo %]−

2[Ni %]−

[Mn %]−

15[C %+N %]”

is −

2.0 or more and +8.0 or less.

5. A 12Cr alloy steel for a turbine rotor as claimed in claim 3, wherein a Cr equivalent weight shown by “

[Cr %]+2[Si %]+1.5[Mo %]−

2[Ni %][Mn %]−

15[C %+N %]”

is −

2.0 or more and +8.0 or less.

6. A manufacturing method of a 12Cr alloy steel for a turbine rotor as mentioned in claim 1 or 2, wherein, in a manufacturing process of said alloy steel, there is carried out neither an adjustment of chemical components in a solidifying process of molten metal when said molten metal, adjusted to predetermined chemical components, is cast in a mold for making a steel ingot nor a re-smelting treatment of said steel ingot once solidified.

7. A manufacturing method of a 12Cr alloy steel for a turbine rotor as mentioned in claim 3, wherein, in a manufacturing process of said alloy steel, there is carried out neither an adjustment of chemical components in a solidifying process of molten metal when said molten metal, adjusted to predetermined chemical components, is cast in a mold for making a steel ingot nor a re-smelting treatment of said steel ingot once solidified.

8. A manufacturing method of a 12Cr alloy steel for a turbine rotor as mentioned in claim 4, wherein, in a manufacturing process of said alloy steel, there is carried out neither an adjustment of chemical components in a solidifying process of molten metal when said molten metal, adjusted to predetermined chemical components, is cast in a mold for making a steel ingot nor a re-smelting treatment of said steel ingot once solidified.

9. A manufacturing method of a 12Cr alloy steel for a turbine rotor as mentioned in claim 1 or 2, wherein, in a heat treatment process of said alloy steel, there are carried out tempering treatments two times or more in a temperature range of 500 to 700°

C. after a quenching treatment.

10. A manufacturing method of a 12Cr alloy steel for a turbine rotor as mentioned in claim 3, wherein, in a heat treatment process of said alloy steel, there are carried out tempering treatments two times or more in a temperature range of 500 to 700°

C. after a quenching treatment.

11. A manufacturing method of a 12Cr alloy steel for a turbine rotor as mentioned in claim 4, wherein, in a heat treatment process of said alloy steel, there are carried out tempering treatments two times or more in a temperature range of 500 to 700°

C. after a quenching treatment.

12. A manufacturing method of a 12Cr alloy steel for a turbine rotor as mentioned in claim 5, wherein, in a heat treatment process of said alloy steel, there are carried out tempering treatments two times or more in a temperature range of 500 to 700°

C. after a quenching treatment.

13. A turbine rotor made of an alloy steel mentioned in claim 1 or 2.

14. A turbine rotor made of an alloy steel mentioned in claim 3.

15. A turbine rotor made of an alloy steel mentioned in claim 4.

16. A turbine rotor made of an alloy steel mentioned in claim 5.

17. A turbine rotor made of an alloy steel mentioned in claim 6.