Preparing Tungsten-Zirconium Alloy with Arc Melting Process

Tungsten is a very important non-ferrous metal. It has the properties of high density and high hardness. It is commonly used in counterweight materials, shielding materials and military materials. Tungsten-zirconium alloy has a broad application prospect in the military field due to its strong resistance to corrosion.

Traditional methods for preparing tungsten-zirconium alloys include non-consumable arc melting and consumable arc melting. Both of these methods use an electric arc as a heat source to melt tungsten and zirconium to form an alloy. Among the two methods, tungsten as a raw material mainly has two types of tungsten powder and pure tungsten chips. Whether it is tungsten powder or tungsten chips, it is mechanically mixed with zirconium sponge and used directly as a raw material for arc melting.

Tungsten chips are millimeter-scale pure tungsten blocks that have formed dense structures. During the arc melting process, only tungsten chips near the center of the arc can reach the melting point and melt, and because of the small specific surface area, only one layer of tungsten can quickly form an alloy with the surrounding titanium and zirconium. When the tungsten content of the mixed raw materials is higher than 10%, it is often difficult to ensure complete melting of all the tungsten chips and further form an alloy of high tungsten content in the arc melting process, and unalloyed tungsten particles often remain in the center of the original pure tungsten block. This directly leads to uneven alloy composition obtained by smelting.

Targeting the above problems, researchers have improved the existing arc melting method of tungsten alloys, so that the tungsten content can reach more than 10%, up to 40%. For example, the process of preparing a Zr-30W alloy includes the following steps:

(1) Tungsten powder compact

The raw material tungsten powder was pressed into a tungsten powder compact on a press at a forming pressure of 500 MPa.

(2) Tungsten powder compaction

The tungsten powder compact prepared in the previous step was crushed into tungsten powder compact particles having a particle size of between 0.1 mm and 5 mm.

(3) Preparation of Materials

The tungsten powder compact particles and the sponge zirconium prepared in the previous step were used as raw materials, and 200 g of the weight percentage was mixed, wherein the tungsten powder compact particles were 30%, and the rest was zirconium sponge.

(4) Vacuum arc melting

The prepared raw materials are placed in a crucible, and the ingot is obtained by three times of melting using a usual vacuum non-consumable arc melting process, and the ingot is cooled to below 200 ° C after each melting. A high tungsten content tungsten-zirconium alloy (Zr-30W) can be obtained after baking.

Compared with the prior art, the improved method has the advantages that the tungsten powder raw material is pre-compressed and broken, and the distribution state of the tungsten powder raw material and other metal raw materials in the smelting process is improved. On the one hand, the pre-compacted tungsten powder can greatly reduce the volume of tungsten powder raw materials, and solve the problem that a large proportion of tungsten powder raw materials are difficult to be mixed with sponge zirconium and other raw materials. On the other hand, the combination of tungsten powder raw materials and other metal raw materials has been obtained. The improvement makes the loose tungsten powder blank during the arc smelting process melt rapidly and form an alloy with the surrounding zirconium, and combined with arc melting, the loose tungsten powder compact melts rapidly during the melting process, and the metallurgical reaction with the surrounding alloy elements is also carried out very well. Completely, a high-tungsten alloy ingot with uniform composition is obtained, and a high-tungsten alloy with uniform composition, no segregation, and no inclusion can be obtained with a tungsten content of up to 40%.

• < Prev
• Next >