Method of manufacturing steam turbine rotor and steam turbine rotor

Patent metadata

Field	Value
Publication number	US-9856735-B2
Application number	US-200913127517-A
Country	US
Kind code	B2
Filing date	Oct 27, 2009
Priority date	Nov 4, 2008
Publication date	Jan 2, 2018
Grant date	Jan 2, 2018

Abstract

A method of manufacturing a steam turbine rotor which includes an ultra-high temperature side portion in which ultra-high temperature steam flows and a high temperature side portion in which high temperature steam flows, the manufacturing method including the steps of: preparing a first electrode having a chemical composition corresponding to a chemical composition of a heat resistant alloy making up the ultra-high temperature side portion and a second electrode having a chemical composition corresponding to a chemical composition of the high temperature side portion; tentatively joining together joints of the electrodes, with the joints of the electrodes made smaller in cross sectional area than other electrode portions; subjecting the tentatively joined first and second electrodes to an ESR process to obtain an ESR ingot and forging the ingot into a shape of a rotor to obtain a rotor forging; and heat-treating the rotor forging to obtain a rotor blank and manufacturing the steam turbine rotor from the rotor blank.

First claim

The invention claimed is:

1. A method of manufacturing a steam turbine rotor which includes an ultra-high temperature side portion in which ultra-high temperature steam flows and a high temperature side portion in which high temperature steam, having a temperature lower than the ultra-high temperature steam, flows, the steam turbine rotor manufacturing method comprising the steps of:
preparing a first electrode having a solid structure and a chemical composition corresponding to a chemical composition of a heat resistant alloy making up the ultra-high temperature side portion and a second electrode having a solid structure and a chemical composition corresponding to a chemical composition of the high temperature side portion;
providing joints on peripheral edges at facing longitudinal end surfaces of the first and second electrodes, wherein the joints are configured such that each joint located only on an outer periphery of the respective electrode protrudes in an axial direction relative to the longitudinal end surfaces;
tentatively joining together the joints of the first and second electrodes, wherein the tentatively joined joints of the first and second electrodes have a cross sectional area smaller than the cross sectional area of the facing longitudinal end surfaces;
subjecting the tentatively joined first and second electrodes to electro-slag remelting so that the tentatively joined joints of the first and second electrodes are eliminated,
forging a resulting electro-slag remelted ingot into a shape of a rotor to obtain a rotor forging; and
subsequently heat-treating the rotor forging to obtain a rotor blank and manufacturing the steam turbine rotor from the rotor blank.

2. The steam turbine rotor manufacturing method according to claim 1 , wherein the chemical composition of the second electrode is different from the chemical composition of the first electrode and the chemical composition of the high temperature side portion of the steam turbine rotor is different from the chemical composition of the ultra-high temperature side portion.

3. The steam turbine rotor manufacturing method according to claim 2 , wherein the high temperature side portion is made of a ferritic heat resistant steel.

4. The steam turbine rotor manufacturing method according to claim 2 , wherein in the heat treatment of the rotor forging, the ultra-high temperature side portion and the high temperature side portion are heat-treated simultaneously under heat treatment conditions predetermined according to the respective chemical compositions.

5. The steam turbine rotor manufacturing method according to claim 1 , wherein the chemical composition of the second electrode is same as the chemical composition of the first electrode, and the high temperature side portion of the steam turbine rotor is made of a same heat resistant alloy as the ultra-high temperature side portion.

6. The steam turbine rotor manufacturing method according to claim 5 , wherein in the heat treatment of the rotor forging, the ultra-high temperature side portion and the high temperature side portion are heat-treated simultaneously under same heat treatment conditions.

7. The steam turbine rotor manufacturing method according to claim 1 , wherein the heat resistant alloy making up the ultra-high temperature side portion is an Ni-based superalloy.

8. The steam turbine rotor manufacturing method according to claim 1 , wherein the steam turbine rotor is one of a high pressure turbine rotor, an intermediate pressure turbine rotor for a turbine having a pressure lower than the turbine of the high pressure turbine rotor, and an integrated high and intermediate pressure turbine rotor.

9. The steam turbine rotor manufacturing method according to claim 1 , wherein the facing longitudinal end surfaces of the first and second electrodes located between the tentatively joined joints are separated from one another to form a gap.

Assignees

• Yamada Masayuki
• Inukai Takao
• Imai Kiyoshi
• Miyashita Shigekazu
• Nemoto Kuniyoshi
• Takaku Reki
• Toshiba Kk

Inventors

• Yamada Masayuki
• Inukai Takao
• Imai Kiyoshi
• Miyashita Shigekazu
• Nemoto Kuniyoshi
• Takaku Reki

Classifications

• Y10T29/49316

  Impeller making · CPC title

• F05D2220/31

  in steam turbines · CPC title

• F01D5/06 Primary

  Rotors for more than one axial stage, e.g. of drum or multiple disc type; Details thereof, e.g. shafts, shaft connections {(F01D5/022, F01D5/023 take precedence)} · CPC title