Tungsten powder. Brand chemical composition.
General characteristics
Tungsten is solid refractory metal, element No. 74 of periodic table, denoted as W, has density of 19.25 g/cm³, melting point 3422 °C and boiling point t above 5500 °C. Tungsten powder is heavy finely divided mass with high hardness and refractoriness. It serves as basis for compact metal. First get piles, which are billets of tungsten rods, wire, sheets, as well as basis for sintering hard heat-resistant alloys by powder metallurgy.
| Atomic (molar) mass g/mol | Oxidation state | Density [g/cm3] |
Melting point t °С | Boiling point t °С | Heat of fusion kJ/kg |
| 183,84 | 0, 2, 3, 4, 5, 6 | 19,25 | 3422°С | 5500°С | 191 |
Grades of tungsten powder
Main brands are: VP, PVV (highly active tungsten powder), PVN (low-activity tungsten powder), PVT (technical tungsten powder). They are produced according to TU 48−19−72−92 «Tungsten powder. Technical conditions». Average grain diameter for PVN and PVT powder is 3.5 — 6 microns (not more than 40% of grains of PVN grade tungsten powder have size of more than 4 microns), PVV 0.8 — 1.7 microns.
Using
Hard and refractory tungsten serves as basis for tool and high-speed steels, wear-resistant and heat-resistant steels, non-consumable electrodes and electric lighting equipment. Tungsten powder is used as main component of tool and high-speed steels or alloying additives, as well as heat-resistant and wear-resistant alloys (such as stellites). Basis of VK hard tungsten-cobalt alloy is tungsten carbide. Tungsten powder produces tungsten non-consumable electrodes for welding.
Tungsten powder is produced in three grades, depending on scope and source of raw materials: TU-48−19−72−79−79 tungsten powder
| Mark | Powder name | Feedstock |
| PVV | highly active tungsten powder | Variety ammonium paratungstate anhydride, grade A, or high purity ammonium paratungstate. |
| PVN | low activity tungsten powder | Variety ammonium paratungstate anhydride, grade A, or low molybdenum ammonium paratungstate. |
| PVT | technical tungsten powder | Ammonium paratungstate tungsten anhydride or ammonium paratungstate. |
| Impurity | PVN | PVV | PVT |
| Al | 0,001 | 0,001 | 0,002 |
| Fe | 0,008 | 0,006 | 0,02 |
| K | 0,02 | 0,02 | 0,02 |
| Ca | 0,005 | 0,002 | 0,005 |
| (O2 and moisture) | 0,25 | 0,35 | 0,2 |
| Si | 0,003 | 0,002 | 0,005 |
| Ni | 0,005 | 0,005 | 0,008 |
| Na | 0,015 | 0,01 | 0,02 |
| Mo | 0,04 | 0,02 | 0,2 |
| As | 0,005 | 0,003 | 0,03 |
| S | 0,004 | 0,004 | 0,004 |
| C | 0,003 | 0,003 | 0,003 |
| P | 0,005 | 0,004 | 0,005 |
Note:
Mass fraction of tungsten is metal base and undetectable accompanying impurities.
Dispersion of tungsten powder, characterized by average particle diameter according to Fisher, and must comply with following standards.
| Mark | According to Fisher, the average grain diameter, microns |
| PVV | from 0.8 to 1.7 |
| PVN | from 3.5 to 6.0 |
| PVT | from 3.5 to 6.0 |
Note:
— in PVN powder, grain content of more than 4 microns should be up to 40%;
— bulk specific gravity of powder of grades PVN and PVT = 3.0 — 5.5 g / cm³;
— bulk density for PVV brand is not rejection criterion and may not be determined.
Buy at bargain price
Wide range of high-quality metal powders at best prices are available at warehouse of LLC Elektrovek-steel. Tungsten powder is supplied in jars with gross weight of up to 70 kg. Warranty period of storage 24 months from moment of production. All products have quality certificate for compliance with standards and specifications. Certificate indicates manufacturer, grade of powder, chemical composition and properties. Fulfillment of orders — in shortest possible time. Wholesale buyers receive preferential discounts.
