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

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.