Method for preparing high-purity nickel-based superalloy by electron beam induced refining and casting technology

Patent metadata

Field	Value
Publication number	US-11981978-B2
Application number	US-202017630905-A
Country	US
Kind code	B2
Filing date	Jun 12, 2020
Priority date	Aug 1, 2019
Publication date	May 14, 2024
Grant date	May 14, 2024

Abstract

A method for preparing high-purity nickel-based superalloy includes the steps of: performing electron beam smelting on small cylinders in a first water-cooled copper crucible after preheating an electron gun, and converging the beam to the edge of one side of the ingot; turning on the electron gun again after completely solidifying the ingot, the electron beam spot uniformly and slowly scanning a surface of the ingot from a side opposite to a final beam converging area of the ingot to the final beam converging area of the ingot to ensure that the alloy at a position scanned by the electron beam spot is completely melted, and stopping scanning once scanning to the final converging area of the ingot; casting the molten alloy in the first water-cooled copper crucible to the second water-cooled copper crucible; taking out the refined nickel-base superalloy after cooling down the electron beam melting furnace.

First claim

The invention claimed is:

1. A method for preparing high-purity nickel-based superalloy by electron beam induced refining and casting technology, comprising the following steps of:
S1. cutting rod-shaped nickel-based superalloy into small cylinders, and cleaning them for later use;
S2. cleaning a furnace body of an electron beam smelting furnace, a surface of a first water-cooled copper crucible and a surface of a second water-cooled copper crucible for later use;
S3. placing the cleaned small cylinders in the middle of a bottom of the first water-cooled copper crucible, and cleaning the furnace body of the electron beam melting furnace, and closing a door of the electron beam melting furnace;
S4. vacuuming the electron beam smelting furnace to a high vacuum, preheating an electron gun after reaching a predetermined vacuum;
S5. performing electron beam melting on the small cylinders in the first water-cooled copper crucible after preheating the electron gun, and converging the electron beam to an edge of one side of an ingot;
S6. turning on the electron gun after completely solidifying the ingot, forming an electron beam spot on a surface of the ingot, wherein the electron beam spot scans a surface of the ingot from a side opposite to a final electron beam converging area of the ingot to the final electron beam converging area of the ingot to ensure that the alloy at a position scanned by the electron beam spot is completely melted, and stopping scanning before reaching the final electron beam converging area of the ingot;
S7. casting the molten alloy obtained in step S6 from the first water-cooled copper crucible to the second water-cooled copper crucible; and
S8. taking out a refined nickel-based superalloy after cooling down the electron beam melting furnace,
wherein step S5 further comprises:
reducing the beam current to 0 mA after preheating the electron gun, turning on the high voltage, increasing the beam current to 400 mA within 2 min after the voltage reaching 30 kV and stabilizing for 1 min, wherein the electron beam spot radius is 10×10;
keeping the melting power unchanged, melting the small cylinder in the first water-cooled copper crucible by adjusting the scanning path of the electron beam spot; and
reducing the beam current after refining for 10 min, and at the same time, reducing the radius of the electron beam spot to reduce the beam current from 400 mA to 0 mA within 5 min and the electron beam spot radius from 10×10 to 0×0, converging the electron beam spot to the edge of one side of the ingot.

2. The method according to claim 1 , wherein in step S1, the cleaning comprises polishing a surface of the small cylinder with a grinder, cleaning the polished small cylinder with deionized water, alcohol, and with an ultrasonic cleaner, and then drying the small cylinder with a hair dryer.

3. The method according to claim 1 , wherein in steps S2 and S3, the treatment method for cleaning the furnace body of the electron beam melting furnace is dust removal treatment.

4. The method according to claim 1 , wherein in step S2, the surfaces of the first water-cooled copper crucible and the second water-cooled copper crucible are polished smoothly with 2000 # sandpaper, and then wiped with a cotton cloth moistened with alcohol.

5. The method according to claim 1 , wherein in step S4, the predetermined vacuum is that a vacuum degree of the electron beam melting furnace body is less than 5×10 −2 Pa, and a vacuum degree of the electron gun chamber is less than 5×10 −3 Pa;
wherein preheating the electron gun comprises turning on the electron gun, adjusting the beam current to 120 mA, and preheating for 12 minutes.

6. The method according to claim 1 , wherein in step S6, after turning on the electron gun, the beam current is increased to 400 mA, and the electron beam spot radius is 5×5.

7. The method according to claim 1 , wherein in step S6, scanning is stopped at a position 1 cm from the final electron beam converging area of the ingot.

8. The method according to claim 1 , wherein in step S8, a method for cooling the electron beam smelting furnace comprises introducing argon into and extracting the argon from the electron beam smelting furnace body after cooling the electron beam smelting furnace for 40 min, and then introducing argon into and extracting the argon from the electron beam smelting furnace body again, and cooling the furnace body of the electron beam smelting furnace until cooling completely.

Assignees

• Univ Dalian Tech

Inventors

• Tan Yi
• Zhuang Xinpeng
• Zhao Longhai
• You Xiaogang
• Li Pengting
• Wang Yinong

Classifications

• C22B9/228 Primary

  by particle radiation, e.g. electron beams · CPC title

• B22D11/116

  Refining the metal · CPC title

• C22C1/023 Primary

  Alloys based on nickel · CPC title

• C22C19/03

  based on nickel · CPC title

• C22C1/02

  by melting {(C22C1/1036 takes precedence)} · CPC title