1) Preparation of doped tungsten powder: the original tungsten (WO2.9) powder and the mixed solution of H2SiO3 and KOH containing SIO2: 0.2~0.6wt% and K2O: 0.2~0.6wt% and containing Al2O3 according to the weight percentage of tungsten powder: 0.02~0.1wt% Al(NO3)3 solution is placed in a stirrer, mixed at 50~60°C for 3~5 hours, then dried at 100~200°C for 3~6 hours to obtain doped Blue tungsten powder;
2) Reduction treatment: Put the doped tungsten powder in a boat and place it in a hydrogen atmosphere at a temperature of 500-950°C for 8-12 hours, and pass through a 100-200 mesh sieve after cooling to obtain the doped tungsten powder;
3) Pickling: First pickle the doped tungsten powder with dilute hydrochloric acid with a concentration of 3~6wt% for 30~60 minutes, then remove the supernatant, then add hydrofluoric acid with a concentration of 3~6wt%, and wash until The Si content in the powder is ≤250ppm, the Al content is ≤30ppm, and then vacuum-dried at a temperature of 70~150°C for not less than 10 hours, and passed through a 160~200 mesh sieve to disperse and remove impurities after drying;
4) Compact: Press the powder obtained in 3 under a pressure of 150~250MPa to make a billet doped with tungsten;
5) Pre-sintering: the pressed billet is placed in a boat and sintered in a hydrogen atmosphere at a temperature of 1100-1400°C for 30-60 minutes;
6) Vertical melting and sintering: place the pre-sintered billet in a vertical melting furnace, and then vertical melting and sintering for 10 to 25 minutes under the condition of hydrogen atmosphere and 70-92% of the current intensity of the fusing current, then cool with the furnace to obtain non-densification Potassium-containing tungsten bars;
7) Indirect sintering: place the tungsten bars obtained in step 6 in an intermediate frequency furnace or a tungsten rod furnace, sinter in a hydrogen atmosphere and at a temperature of 2000~2300°C for 2~6 hours, and obtain the target potassium-containing metal tungsten bars after cooling with the furnace.
The high-purity tungsten rod produced by Baoji Yusheng Metal Technology Co., Ltd. has a complete production process system. We guarantee that every tungsten rod product we provide to our customers meets its production standards.
