Preparation method of nickel-manganese intermediate alloy

The invention discloses a preparation method of a nickel-manganese intermediate alloy. The preparation method comprises the following steps of a, 30%-60% of nickel and the balance manganese are takenaccording to the weight ratio; b, a part of the nickel is put into the bottom part of a crucible, then carbon is put into the crucible, the rest nickel is further put into the crucible, the manganeseis put into an alloy bin, and a small amount of nickel-magnesium alloy and the carbon are also put into the alloy bin; and c, when vacuumizing is carried out until the air pressure in the crucible issmaller than or equal to 5 pa, heating and smelting are started, heating power is increased to 25kw according to a heating method that the heating power is increased by 2-5kw every 5 minutes when theheating power is below 25kw, then the heating power is increased to 30kw according to a heating method that the heating power is increased by 5kw every 10 minutes, after materials in the crucible arecompletely melted until a liq