Electrode paste sintering process
Although there is no obvious change in the changing process of the electrode paste during sintering, it can be roughly divided into various stages according to the firing temperature and position. This process is carried out without external pressure and solely on the weight of the paste itself.
1. The softening stage. At this time, the solid electrode paste melts, the resistance increases, and the strength decreases, and finally all the electrode paste becomes a liquid state. At this stage the temperature is 25. C rises to 120~200. C, about 500 mm above the conductive jaw.
2. The volatilization stage. At this time, the electrode paste is fully melted, flows along the inner section of the shell, fills the gaps, and makes the quality uniform, and at the same time, it volatilizes and becomes viscous gradually. The resistance keeps decreasing, and the volatilization becomes a paste. At this stage, the temperature changes from 120 to 200. C rises to 650~750. C, roughly in the half-ring position.
3. Sintering stage. At this time, a small amount of volatile matter continues to volatilize, and further sintering begins, the conductivity is greatly increased, and it becomes a hard whole. The height of the complete sintering is 200-400 mm below the conductive jaw, and the temperature at this time is 650-750. C rises to 700~1000. C.
The electrode is oxidized on the surface, the reaction in the furnace, and the electrode is gradually burned out during arc burning, so it is necessary to control the sintering according to its consumption and lower the sintered electrode into the furnace to keep it at an appropriate working length and density.