Sources of Tungsten Rods and Preparation Steps

There are three types of Tungsten Rods: sintered Tungsten Rods with a silver-grey metallic luster; wrought Tungsten Rods with a layer of oxide and a black surface; and polished Tungsten Rods with a silver-grey metallic luster. So, do you know how to prepare Tungsten Rods, then let's take a look at the sources of the tungsten alloy rod and the steps to prepare them. Here are some answers.

Here is the content list:

l The origin of Tungsten Rods.

l Preparation of Tungsten Rods.

The origin of Tungsten Rods.

Tungsten is one of the few non-ferrous minerals in the world that is produced in very low annual quantities and is used in a wide range of applications, mainly as a raw material for foundry ingredients. Tungsten comes from a white sandy ore body with a particularly small ore line. After several processes such as mining, grinding, water re-election, and refining, tungsten ore powder with a grade of over 95% is obtained and then refined and shaped in a high-temperature electric furnace to produce the finished product which is the tungsten bar. The melting point of tungsten is 3500°C. Tungsten ores are mainly found in China and Russia, and China is now the world's largest exporter of tungsten. The purity of Tungsten Rods should normally be above 99.95% and must be tested by an authoritative body, such as the National Centre for Analysis and Testing of Non-Ferrous Metals and Electronic Materials.

Preparation of Tungsten Rods.

Firstly, raw tungsten (WO2.9) powder and a mixed solution of H2SiO3 and KOH containing SIO2 (0.2 to 0.6 wt%) and K2O (0.2 to 0.6 wt%) and Al (NO3)3 solution containing Al2O3 (0.02 to 0.1 wt%) by weight of tungsten powder are placed in a stirrer and mixed at a temperature of 50 to 60°C for 3 to 5 hours and then the doped tungsten powder was dried at a temperature of 100 to 200°C for 3 to 6 hours to obtain the doped tungsten powder. Secondly, the doped tungsten powder is reduced in a boat at a temperature of 500 to 950°C and under a hydrogen atmosphere for 8 to 12 hours, cooled, and sieved through 100 to 200 mesh to obtain the doped tungsten powder. Thirdly, the doped tungsten powder is acid washed with dilute hydrochloric acid at a concentration of 3 to 6 wt% for 30 to 60 minutes. The upper layer is then drawn off and hydrofluoric acid at a concentration of 3 to 6 wt% is added. The powder is washed until the Si content is ≤250ppm and the Al content is ≤30ppm, then dried under vacuum at 70 to 150°C for not less than 10 hours. Fourthly, the powder obtained from treatment 3 is pressed into doped tungsten billets under a pressure of 150 to 250 MPa. Fifth, the pressed billets are placed in a boat and sintered in a hydrogen atmosphere at 1100 to 1400°C for 30 to 60 minutes. Sixthly, the pre-sintered billets are placed in a pendant furnace and sintered for 10 to 25 minutes in a hydrogen atmosphere and at 70 to 92% of the current strength of the fusing current, and then cooled to obtain potassium-containing Tungsten Rods. After sintering for 2 to 6 hours and cooling in the furnace, the target product is obtained as a tungsten carbide rod containing potassium metal.

For more information about Tungsten Rods, please feel free to contact Changsha Jingxin Cemented Carbide Co. With years of accumulated experience in R&D and production, we can provide you with more product services and technical support! Our official website is https://www.7jinxin.com/.