Preheat treatment method for 25Cr2Ni4MoV steel generator rotor

A technology of generator rotor and preparatory heat treatment, applied in heat treatment furnaces, heat treatment equipment, furnace types, etc., can solve the problems of many normalizing times and complicated operations, and achieve the effects of less stress risk, simple operation, and shortened heat treatment time.

Inactive Publication Date: 2018-08-07
CHINA ERZHONG GRP DEYANG HEAVY IND
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  • Application Information

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Problems solved by technology

[0004] The technical problem solved by the present invention is to provide a preparatory heat treatment method for the rotor of a 25Cr2Ni4MoV steel generator, which solves the problem that the rotor of a large-diameter 25Cr2Ni4MoV steel generator has many times of normalizing and the operation is complicated

Method used

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  • Preheat treatment method for 25Cr2Ni4MoV steel generator rotor
  • Preheat treatment method for 25Cr2Ni4MoV steel generator rotor
  • Preheat treatment method for 25Cr2Ni4MoV steel generator rotor

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Embodiment 1

[0041] Use the following scheme for the diameter of The 25Cr2Ni4MoV steel generator rotor is heat treated: its process diagram refers to figure 2 .

[0042] (1) After forging, enter the 600-650°C waiting furnace for uniformity and stress relief treatment. The holding time is 10h, and the furnace temperature is rapidly (90°C / h) cooled to 520±20°C, and held for 35h.

[0043] (2) After the 520±20°C platform heat preservation is completed, cool to 200-240°C at a cooling rate of 10°C / h, and keep the heat for 40 hours.

[0044] (3) After the 200-240°C platform heat preservation is completed, heat to 600-620°C at a heating rate of 10°C / h, and hold for 53 hours.

[0045] (4) After the 600-620°C platform heat preservation is completed, heat it to 900±10°C at a heating rate of 30°C / h, and keep it warm for 53 hours after the surface reaches temperature.

[0046] (5) After the 900±10°C platform heat preservation is completed, cool to 650±10°C at a cooling rate of 20°C / h, and keep the h...

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Abstract

The invention relates to a preheat treatment method for a 25Cr2Ni4MoV steel generator rotor, belonging to the technical field of heat treatment of large-diameter generator rotors. The invention aims at providing the preheat treatment method for the 25Cr2Ni4MoV steel generator rotor. The preparation method comprises the steps of heating the rotor to an austenitizing temperature, maintaining the temperature, cooling to enter fluctuation heat preservation stage, finally, cooling to 250 DEG C, and discharging, wherein the step a is repeatedly carried out for at least two times and comprises the steps of sequentially maintaining the temperature at a temperature T1 and a temperature T2, T1 is a perlitic transformation temperature, and the T2 is 20-50 DEG C lower than T1. According to the preparation method, the problems of more normalization number of times, complex operation and the like of the large-diameter 25Cr2Ni4MoV steel generator rotor can be effectively solved, and the stress cracking risk in the normalization process is reduced; and the preparation method has the advantages of simplicity in operation, stable quality, lowering of cost, low stress risk, short process period and the like.

Description

technical field [0001] The invention relates to a preparatory heat treatment method for a 25Cr2Ni4MoV steel generator rotor, belonging to the technical field of heat treatment of a large-diameter generator rotor. Background technique [0002] The large-diameter generator rotor is a key part of power generation equipment. The forming and manufacturing of high-quality rotor forgings includes smelting, ingot casting, forging and heat treatment. Among them, the selection of heat treatment process is the key to determine the internal quality and final performance of the rotor. Directly affect operational reliability. [0003] 25Cr2Ni4MoV steel contains more Cr, Ni, Mo, and has good hardenability. It is mainly used in the manufacture of steam turbine generator rotors. The uniformity has very high requirements. In order to meet the above requirements, the heat treatment process mode currently adopted is normalizing and tempering + modulation treatment, and the large diameter rotor...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21D1/28C21D8/00C21D9/00C21D6/00C22C38/02C22C38/04C22C38/44C22C38/46
CPCC21D1/28C21D6/004C21D6/005C21D6/008C21D8/005C21D9/0068C22C38/02C22C38/04C22C38/44C22C38/46
Inventor 李其阳鹤沈国劬蒋新亮
Owner CHINA ERZHONG GRP DEYANG HEAVY IND
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