A Preparation Method of Tungsten-Titanium Alloys with Arc Melting

Tungsten is a very important non-ferrous metal. It has a series of properties such as high density and high strength. It is commonly used in counterweight materials, shielding materials, military firing materials, semiconductor materials, etc.

Tungsten and titanium are important metallurgical additives, mainly used in the manufacture of high-hardness tungsten steel, tungsten-titanium alloy, etc. The tungsten-titanium alloy combination has high strength, high hardness, and lighter weight.

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

In order to solve this problem, some scholars have proposed an arc melting method of high tungsten content tungsten alloy, the tungsten content can reach more than 10%, 40% at top. The preparation method of the tungsten-titanium alloy is as follows:

(1) Tungsten  powder compaction

The raw material tungsten powder was pressed into a tungsten powder compact on a press, and the compact pressure was 50 MPa.

(2) Tungsten compact being crushed

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) Additives

The tungsten powder compact particles and the sponge titanium prepared in the previous step were used as raw materials, and 200 g were mixed by weight, wherein the tungsten powder compact particles were 10%, and the rest was sponge titanium.

(4) Vacuum arc melting

The prepared raw materials are placed in a crucible, and the ingot is obtained by two times of melting using a usual vacuum non-consumable arc melting process, and the ingot is cooled to below 200 ° C after each melting. High tungsten content tungsten-titanium alloy (Ti-10W) can be obtained after baking.

The product obtained above was cut into the skin by a lathe, and the block and chip samples were taken at the head, middle and bottom of the ingot for component analysis. The analysis results showed that the composition of tungsten in the alloy was uniform.

Compared with the current process, the new preparation method has the advantages that the tungsten powder raw material is pre-compressed and crushed, 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-compressed 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 mix with raw materials such as sponge titanium. On the other hand, the combination of tungsten powder raw materials and other metal raw materials has been obtained. Improvement, so that the loose tungsten powder billet during the arc melting process can be quickly melted and alloyed with the surrounding titanium, 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 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%.

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