Method for producing metal ingot

Patent metadata

Field	Value
Publication number	US-11833582-B2
Application number	US-201816604906-A
Country	US
Kind code	B2
Filing date	Apr 13, 2018
Priority date	Apr 13, 2017
Publication date	Dec 5, 2023
Grant date	Dec 5, 2023

Abstract

A method for producing a metal ingot by using an electron-beam melting furnace including an electron gun and a hearth that accumulates a molten metal of a metal raw material, in which, in a downstream region between an upstream region in which the metal raw material is supplied onto the surface of the molten metal and a first side wall, an irradiation line is disposed so as to block a lip portion and so that two end portions are positioned in the vicinity of the side wall of the hearth. A first electron beam is radiated onto the surface of the molten metal along the irradiation line, such that the surface temperature (T 2 ) of the molten metal along the irradiation line is made higher than the average surface temperature (T 0 ) of the entire surface of the molten metal in the hearth.

First claim

The invention claimed is:

1. A method for producing a metal ingot by using an electron-beam melting furnace having an electron gun capable of controlling a radiation position of an electron beam, and a hearth that accumulates a molten metal of a metal raw material, the metal ingot containing 50% by mass or more in total of at least one metallic element selected from titanium, tantalum, niobium, vanadium, molybdenum and zirconium, said method comprising:
radiating a first electron beam onto a surface of the molten metal along an irradiation line, wherein:
among a plurality of side walls of the hearth that accumulate the molten metal of the metal raw material, a first side wall is a side wall provided with a lip portion for causing the molten metal in the hearth to flow out into a mold;
the irradiation line is disposed in a downstream region between an upstream region in which the metal raw material is supplied onto the surface of the molten metal and the first side wall, such that the irradiation line blocks the lip portion, and two end portions of the irradiation line are positioned at an inside face of any of the plurality of side walls of the hearth, or in a region in which a separation distance from an inside face of any of the plurality of side walls of the hearth is 5 mm or less;
the irradiation line has a convex shape that projects from the lip portion side toward the upstream, and is in a V-shape, or a circular arc shape having a diameter that is equal to or larger than an opening width of the lip portion;
a radiation position of the first electron beam runs between the two end portions of the irradiation line, such that the irradiation line on the surface of the molten metal is repeatedly scanned with said first electron beam emitted from the electron gun; and
the radiation of the first electron beam along the irradiation line increases a surface temperature (T 2 ) of the molten metal at the irradiation line above an average surface temperature (T 0 ) of the entire surface of the molten metal in the hearth, and forms, in an outer layer of the molten metal, a molten metal flow toward upstream that is a direction toward an opposite side to the first side wall from the irradiation line, wherein radiation conditions are set such that the molten metal flow can be formed and constantly maintained.

2. The method for producing a metal ingot according to claim 1 , wherein the molten metal flow is a flow from the irradiation line that arrives at a side wall that extends substantially perpendicularly toward the upstream from the first side wall among the side walls of the hearth.

3. The method for producing a metal ingot according to claim 1 , wherein a plurality of the first electron beams are radiated along the irradiation line using a plurality of electron guns, so that radiation paths of the first electron beams intersect or overlap on the surface of the molten metal.

4. The method for producing a metal ingot according to claim 1 , wherein:
the hearth comprises one refining hearth only; and
the metal raw material is melted at a raw material supplying portion, the melted metal raw material is caused to drip from the raw material supplying portion into the hearth, and the metal raw material in the molten metal is refined within the refining hearth.

5. The method for producing a metal ingot according to claim 1 , wherein:
said hearth has multiple stages, and includes a plurality of divided hearths combined and successively disposed; and
in each of the divided hearths:
the first electron beam is radiated onto the surface of the molten metal along the irradiation line, and the irradiation line is disposed such that the irradiation line blocks a lip portion of each of the divided hearths in the downstream region, and two end portions of the irradiation line in each of the divided hearths are positioned in a region in which a separation distance from an inside face of a side wall of each of the divided hearths is 5 mm or less.

6. The method for producing a metal ingot according to claim 1 , wherein the metal raw material contains 50% by mass or more of a titanium element.

Assignees

• Nippon Steel Corp

Inventors

• Funagane Hitoshi
• Hamaogi Kenji

Classifications

• B22D7/005 Primary

  from non-ferrous metals · CPC title

• B22D11/116

  Refining the metal · CPC title

• B22D21/06

  Casting non-ferrous metals with a high melting point, e.g. metallic carbides (B22D21/02 takes precedence) · CPC title

• B22D27/02

  Use of electric or magnetic effects {(for continuous casting B22D11/015, B22D11/11)} · CPC title

• B22D35/04

  into moulds, e.g. base plates, runners · CPC title