Industry News

New Application Of Tungsten Powder-Indirect Metal 3D Printing Tungsten Alloy Powder

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Update time : 2020-06-26 19:13:43

Tungsten powder is greyish black metal with metallic lustre (body-centred cubic crystal). Melting point 3400℃. Boiling point 5555℃. The hardness of tungsten powder is the hardest among metals. The hardness of the sintered tungsten bar is 200-250. and the tungsten rod after the rotary hammer is 350-400. Mixed with acid dissolved in nitric acid and the hydrofluoric acid. Melt with the mixture of sodium hydroxide and the sodium carbonate. Slightly soluble in the nitric acid, sulfuric acid and aqua regia; and insoluble in water, hydrofluoric acid, potassium hydroxide. There are two variants of tungsten powder, a and B. At standard temperature and normal pressure, type a is a stable body-centred cubic structures. B-type tungsten powder can only appear in the presence of oxygen. It is stable below 630 ℃, it is converted to tungsten above 630 ℃, and this process is irreversible.


In addition to specific requirements on the impurity content of tungsten powder, the oxygen content should be controlled within a particular range. The particle size of commonly used tungsten powder is generally Fischer's average particle size two~10μm. The tungsten powder is in the shape of polygonal particles. Besides, the specific surface, bulk density, and tap density of tungsten powder also vary within a particular range. The performance of tungsten powder has a direct impact on the production of tungsten materials, and the quality of tungsten powder metallurgy products, especially the effect of purity and particle size is more prominent. Tungsten powder is classified according to virtue and particle size and different uses.


The melting point of tungsten powder is the highest of all metal elements, the density (19.3 g/cm) is very high, and the hardness of tungsten is also very high. For example, the hardness of tungsten carbide is close to that of the diamond. Besides, tungsten also has good electrical and thermal conductivity, small expansion coefficient and other characteristics, so it is widely used in kinds of alloys, electronics, chemicals and other fields, of which cemented carbide is the largest consumer of tungsten.


Tungsten metal is a typical refractory metal, difficult to form materials, and difficult to process through metal 3D printing technology. According to the market observations of 3D Science Valley, a small number of companies are currently exploring the manufacture of pure tungsten and tungsten alloys through electron beam melting (EBM) and selective laser melting (SLM) 3D printing based on the powder bed process. Both technologies are direct Metal 3D printing technology. Tungsten powder manufacturers are advancing the development of two tungsten alloy powders. Unlike the previous tungsten alloy 3D printing powders, these two tungsten alloy materials will be used for indirect metal 3D printing technology of binder injection.


Explore tungsten alloy

New design feasibility

Tungsten powder manufacturers are developing two tungsten-based alloy powder materials based on binder jet metal 3D printing technology, cemented carbide (WC-Co) and copper tungsten (Cu-W).


Cemented carbide (WC-Co) is a material with very high hardness and toughness, which is widely used in the production of cutting tools and wear-resistant parts. Copper tungsten (Cu-W) materials are suitable for use in environments requiring high heat resistance, high electrical and thermal conductivity, and low thermal expansion.


The traditional manufacturing process of tungsten metal is to press tungsten carbide powder into the desired shape, and then increase the strength and density of the parts through the sintering process. Through binder jet metal 3D printing technology, tungsten metal powder can be formed without a mould and then combined with traditional sintering and other methods for post-processing to obtain the ultimate strength. The application of 3D printing technology can not only save mould manufacturing time and cost but also realize more complicated parts design and increase the added value of parts.

In addition to developing tungsten alloy 3D printing materials, tungsten powder manufacturers also provide 3D printing services for cemented carbide parts, hoping to help applications explore the new design feasibility of tungsten metal.


3D Science Valley

Tungsten powder manufacturers also provide tungsten alloy powders for 3D printing of EBM and SLM metals. While developing powders, the 3D printing process parameters of tungsten alloy materials were studied. Tungsten powder manufacturers have conducted a study with their partners entitled "Direct Metal Laser Sintering / Selective Laser Melting of Tungsten Powders" to determine the effect of tungsten powder densification Key process parameters, which are essential for manufacturing complex parts with excellent mechanical properties. The research team also studied the feasibility of low apparent density of little spherical powder as the raw material for selective laser melting 3D printing.


For 3D printing applications of pure tungsten or tungsten alloys, according to the market research of 3D Science Valley, Philips medical imaging component manufacturer Smit R ntgen has manufactured a series of genuine tungsten parts through metal 3D printing equipment, such as SLM 3D printing manufacturing pinhole collimator parts in X-ray equipment. 3D printing is beneficial for creating thin-walled parts, which brings excellent manufacturing freedom to the collimated aperture angle and shape. GE, another medical imaging giant, has also developed a tungsten metal collimator through metal 3D printing technology. Besides, GE Additive Manufacturing provides EBM 3D printing technology that can manufacture high-temperature materials such as nickel-based superalloys and tungsten.


Besides, a few other companies are also developing additive manufacturing applications for tungsten metal materials. A few companies have developed 3D printed parts for tungsten alloys using SLM 3D printing equipment. The whole parts adopt a thin-walled structure with a minimum wall thickness of only 0.1mm. Besides, the company has researched the components of WC-Co cemented carbide layer-diamond composite material and material additive manufacturing process based on EBM 3D printing technology. This technology aims to solve the problem of peeling of carbide tool coating. Additive manufacturing process and materials realize the chemical bonding of diamond coating materials and WC-Co cemented carbide layer.

Indirect metal 3D printing, represented by binder jet metal 3D printing technology, has gained considerable attention in industry at the high speed and low cost. Whether the indirect 3D printing technology of tungsten alloys being promoted by tungsten powder manufacturers will bring quick and lower-cost mass-production solutions for tungsten alloy applications, 3D Science Valley will remain concerned.

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