Production method for maraging steel and production method for maraging steel consumable electrode

Patent metadata

Field	Value
Publication number	US-10316377-B2
Application number	US-201515325561-A
Country	US
Kind code	B2
Filing date	Jul 15, 2015
Priority date	Jul 16, 2014
Publication date	Jun 11, 2019
Grant date	Jun 11, 2019

Abstract

The invention provides a maraging steel production method in which an oxide is added during an Mg oxide formation step, the production method including: the Mg oxide formation step in which Mg is added to molten steel and MgO is formed in the molten steel, during primary melting; a consumable electrode production step in which, after the Mg oxide formation step, the molten steel is solidified and a consumable electrode having residual MgO is obtained; and a vacuum arc re-melting step in which the consumable electrode is used and vacuum arc re-melting is performed.

First claim

The invention claimed is:

1. A method for producing a maraging steel, comprising:
a magnesium oxide formation step including adding an amount of magnesium into a molten steel in a primary vacuum melting process to form MgO in the molten steel;
a consumable electrode production step including solidifying the molten steel after the magnesium oxide formation step to obtain a consumable electrode including MgO; and
a vacuum arc remelting step including vacuum arc remelting with use of the consumable electrode to produce a maraging steel,
wherein the magnesium oxide formation step includes adding an amount of an oxide having a higher standard free energy of formation than MgO; and
wherein the maraging steel after the vacuum arc remelting comprises, by mass,
not more than 0.1% of carbon;
0.01 to 1.7% of aluminum;
0.2 to 3.0% of titanium;
8 to 22% of nickel;
5 to 20% of cobalt;
2 to 9% of molybdenum;
not more than 0.0030% of magnesium, and
the balance being iron and impurities.

2. The method according to claim 1 , wherein a steel ingot produced in the vacuum arc remelting has a diameter of not less than 450 mm.

3. The method according to claim 1 , wherein the oxide is an oxide of iron, nickel, manganese, silicon, chromium, molybdenum and/or cobalt.

4. The method according to claim 1 , wherein the amount of the oxide to be added is 0.01% to 1.0% of a weight of the molten steel.

5. The method according to claim 1 , wherein the oxide is added within ten minutes after the addition of magnesium.

Assignees

• Hitachi Metals Ltd

Inventors

• Kamimura Takahiko
• Hadano Yuuichi
• IMAZEKI Kenta
• Ohishi Katsuhiko

Classifications

• C22B9/20

  Arc remelting · CPC title

• C21C7/04

  Removing impurities by adding a treating agent · CPC title

• C22C38/105

  containing Co and Ni · CPC title

• C21C7/0006 Primary

  Adding metallic additives · CPC title

• C22C38/12

  containing tungsten, tantalum, molybdenum, vanadium, or niobium · CPC title