The flow meter is used to measure the flow rate and speed of the liquid when it is flowing. Typically, the movement shaft of a flow meter is made of stainless steel. It is well known that stainless steel has good corrosion resistance. The corrosion resistance of stainless steel depends on the alloying elements contained in the steel. Chromium is the basic element for obtaining corrosion resistance of stainless steel. In addition to chromium, commonly used alloying elements include nickel, molybdenum, titanium, niobium, copper, and nitrogen to meet the requirements of stainless steel structure and properties for various applications.

However, the flow shafts, which are exposed to chemicals such as strong acids and alkalis for a long time, would be corroded. In addition, stainless steel is added with other alloying elements, which makes the steel material impure, so there will be deviations in the magnetic field, resulting in inaccurate measurement. In order to improve the acid-base resistance of the material without magnetic properties, some scholars have proposed a preparation method of tungsten-nickel cemented carbide by:

The raw materials are prepared by weight percentage: 90% tungsten alloy (WC) powder, 9.6% nickel (Ni) powder and 0.4% chromium carbide (Cr3C2) powder; after the raw materials are subjected to mixed ball milling for 36 hours, the material is precipitated for 24 hours and dried for 100 minutes. ± 5 minutes, the temperature is controlled at 85 ° C ± 5 ° C; and then mixed with 10 ml of glue per 1 Kg of mixed raw materials, add SBS-modified binder (0.1Kg of SBS-modified binder per 1Kg of mixed raw materials); finally sintered in a vacuum furnace, control from 300 ° C to 1450 ° C, and then cool down to normal temperature, the product is released.

The WC powder has a particle size of 2.3 to 2.8 μm, the Ni powder has a particle size of 1.5 to 2.0 μm, and the Cr3C2 has a particle size of 2.0 to 2.6 μm.

Because WC powder, Ni powder and Cr3C2 powder are used as alloying elements, the acid and alkali resistance of the material can be improved, the service life is greatly prolonged, and nickel is used instead of the conventional cobalt in the material, so that the material is not magnetic, so it is made. The tungsten-nickel cemented carbide can be used to make the movement shaft of the acid-base flow meter and the movement shaft of the instrument that needs to avoid magnetic interference.

Pure tungsten and tungsten-based high specific gravity alloy materials have the advantages of high melting point, high density, high strength, high hardness and high wear resistance. In addition, it has small thermal expansion coefficient, good corrosion resistance and oxidation resistance, and good electrical and thermal conductivity. Therefore, it has been widely used in semiconductor industry, defense industry and aerospace. It is used as a counterweight and shock absorbing material on aircraft; it is used as armor-piercing projectiles and submunitions in military industry; it is used as an anti-X-ray shielding material in the medical industry; it is used as a high-specific gravity alloy on Vibrator electrode material of mobile phones, etc.

Tungsten is mainly enriched in the granite contact metamorphic zone in the crust, and is more or less symbiotic with tin containing minerals in many tungsten deposits, especially porphyry-type tungsten deposits - such tungsten-containing polymetallic vulcanization ore is often associated with tin-containing minerals.

It is well known that the movement of mechanical parts is always accompanied by friction and wear, which is generally lubricated in order to reduce the friction and wear between moving mechanical parts. The solid lubricating film material has been widely used because it has the advantages of avoiding contamination of industrial parts by liquid lubrication, and being able to work under severe conditions such as low temperature and high temperature.

The alkali extraction method is the main method for smelting tungsten concentrate. Due to its strong adaptability to raw materials and high extraction rate, it has become the mainstream process for processing tungsten mineral raw materials. However, in the actual tungsten smelting process, a high tungsten leaching rate is required, and the consumption of NaOH is large. For example, when processing a wolframite concentrate, the NaOH consumption is 1.5 to 2 times the theoretical amount when 99% leaching rate is obtained. When the scheelite concentrate is treated, the NaOH consumption is even 3 to 4 times of the theoretical amount.

Tungsten oxide has the unique physical properties such as photochromism, electrochromism, thermochromism and gas sensitivity. The color changes can be achieved by changing the wavelength, changing the temperature or applying voltage. Therefore, the transition metal tungsten oxide can be used in many fields, such as various sensors, electronic devices, and so on, because of its advantages. The development of Vietnam has become a hot topic all over the world.

The band gap of tungsten bronze (MxWO₃) is about 2.7 eV, and it has free-migrating electrons. It is one of the most suitable materials for transparent and thermal insulation. Research shows that tungsten bronze materials have better transparency and heat insulation than ITO, ATO, AZO and GZO. It is one of the effective means of saving energy for building or automobile glass. It is a kind of high quality filter for infrared light, and it can be coated on the surface of glass or plastic film to form a transparent insulation coating.

In the process of hydrometallurgy of tungsten, sodium tungstate solution is adsorbed by ion exchange resin, and the wastewater is discharged directly. Due to the limitations of the ion exchange process and the complexity of the raw materials, the WO₃ content in the wastewater after ion exchange is always maintained at a certain value, most of which are larger than 0.05g/l. This not only increases the cost of production and consumption of tungsten resources, but also increases the cost of environmental management.

Generally speaking, it is a good way to separate tungsten carbide powder by electrolysis. The methods of recovering tungsten carbide by the usual electrolysis process are not completely electrolyzed, the cobalt can not be completely separated and removed and the surface wear of the crusher and ball mill is introduced into the process. The Fe, Ni, Co and other impurities in the tungsten carbide powder are over 0.6%, respectively, and the production of high performance cemented carbides is produced. There is a big gap between the high purity technical standards of Fe, Ni and Co, which are not more than 0.1%, so that the scope of the use of tungsten carbide in the electrolysis process is greatly limited.

The rock drilling speed is one of the important indicators for the quality of tungsten carbide button bit. In the case of fixed models, lithology, operating systems, etc., the geometric parameters of the bit have a great influence on the rotational speed. The geometric parameters of the button bit include its shape, number, diameter, the distribution of button, the powder discharge system, the tooth height, incline angle of side teeth and so on