The sintering of tungsten steel is to press the powder into a billet, then heat it into a sintering furnace to a certain temperature (sintering temperature), keep it for a certain time (holding time), and then cool it down to obtain the tungsten steel material with the required properties.
Four basic stages of tungsten steel sintering process:
In the stage of removing the forming agent and pre-sintering, the following changes occur in the sintered body at this stage:
Removal of the forming agent, as the temperature rises in the initial stage of sintering, the forming agent gradually decomposes or vaporizes, and the sintered body is excluded. The type, quantity and sintering process vary.
The oxides on the powder surface are reduced. At the sintering temperature, hydrogen can reduce the oxides of cobalt and tungsten. If the forming agent is removed and sintered in vacuum, the carbon-oxygen reaction is not strong. The contact stress between powder particles is gradually eliminated, the bonded metal powder begins to recover and recrystallize, surface diffusion begins to occur, and the compact strength increases.
Solid phase sintering stage (800°C–eutectic temperature)
At the temperature before the liquid phase appears, in addition to continuing the process that occurred in the previous stage, the solid phase reaction and diffusion intensify, the plastic flow is enhanced, and the sintered body shrinks significantly.
Liquid phase sintering stage (eutectic temperature – sintering temperature)
When the liquid phase appears in the sintered body, the shrinkage is completed quickly, followed by crystallization transformation to form the basic structure and structure of the alloy.
Cooling stage (sintering temperature – room temperature)
At this stage, the structure and phase composition of tungsten steel change with different cooling conditions. This feature can be used to heat treat tungsten steel to improve its physical and mechanical properties. Xin Tenghui CNC has developed a special ceramic engraving and milling machine for ceramic processing. The ceramic engraving and milling machine is a special high-speed engraving and milling machine for ceramics with good protection performance and high processing precision. The ceramic engraving and milling machine strengthens the rigidity of the machine tool, the vibration generated during processing can be minimized, and the processing efficiency can be improved while ensuring the accuracy. Moreover, the protection performance is strengthened for the ceramic powder, which can completely prevent the powder from damaging the machine tool. Ceramic processing technology can also be provided, with a skilled CNC tungsten machining and grinding team, research and development of precision parts and custom processing, etc.