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Vacuum Arc Melting of TZM Alloy

There are two main methods for TZM alloy production: one is the powder metallurgy method and the other one is vacuum arc melting method. TZM alloy vacuum arc smelting process including: electrode production, water cooling effects, stable arc stirring and melting power. Good smelting process has a certain impact on the quality of TZM alloy. In order to produce good performance TZM alloy should be strict requirements on its smelting process.

Electrode requirements: the ingredients of electrode should be uniform; electrode no bending, should meet the requirement of straightness; electrode should be dry, bright, no oxidation; electrode should tie up tightly.

Water cooling effect: in vacuum arc melting furnace, there are two mainly function of crystallizer water cooling effect: one is to take away the heat released during melting, making sure that crystallization will not be burned; the other is affecting the inside organization of ingot, which is heating ingot’s bottom and all around making ingot produced directional columnar grain structure. When melting TZM alloy, cooling water pressure controlling in 2.0 to 3.0 kg / cm2, the water layer about 10mm is best.

Arc stable stirring: during melting TZM alloy, to plus a coil parallel circling with crystallizer and, after powder on forming magnetic field. The main role of the magnetic field is constraining the arc and making the molten pool to solidify under stirring condition. The arc constraining effect is called "arc stable." In addition, to take appropriate arc stability magnetic field intensity can reduce crystallizer breakdown.

Melting power: the power of the melting means melting current and voltage, and it is important process parameters. Inappropriate parameters can cause failure of TZM alloy smelting. Selecting the appropriate melting powder is close related with electrical machine and crystallizer size. The "L" is refer to the distance between the electrode and the crystallizer wall, then the lower value L is, the greater coverage area of ​​the arc on weld pool, and at the same powder the pool heating state is better, the more active the pool. On the contrary, the operation will be difficult and crystallizer is easy to damage.

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