Sintering Process and Use of the Sintering Furnace

---

1. Sintering Process

Sintering: Heat treatment of the powder or compact at a temperature lower than the melting point of the main component aims to improve its strength through metallurgical bonding between particles.

Packing material: A material in which the compact is embedded in order to separate and protect it during the pre-sintering or sintering process.

Presintering: Heat treatment of the compact at a temperature lower than the final sintering temperature.

Pressure: A sintering process in which uniaxial pressure is applied while sintering.

Loose-powder sintering,gravity sintering: Sintering of powder without pressing

Liquid-phase sintering: A powder or compact having at least two components is sintered in a state where a liquid phase is formed.

Oversintering: Sintering where the sintering temperature is too high and/or the sintering time is too long to deteriorate the final performance of the product.

Undersintering: The sintering temperature is too low and (or) the sintering time is too short, so that the product does not reach the required performance of sintering.

2. Use of the Sintering Furnace

a. When using hydrogen or decomposing ammonia, nitrogen must be introduced first, and only when the air in the furnace is completely exhausted can it be energized to increase temperature to prevent screaming and explosion.

b. For sintering furnaces that use molybdenum wire as a heating element, a protective gas should be introduced into the furnace body before energization to prevent the molybdenum wire from being oxidized and brittle.

c. The door and gas outlet of the furnace should be burnt out with an open flame to prevent the risk of explosion and gas poisoning due to the ingress of oxygen or the discharge of hydrogen.

d. If the heating element is iron-chromium-aluminum resistance wire, it should stay for a period of time (about 30min) when the temperature is raised to 1100°C and then heat up to prevent the resistance wire surface temperature from being damaged due to excessively high surface temperature.

e. Check whether the air flow and water flow meet the requirements from time to time before and during operation, and check whether the control instruments of equipment, electricity and furnace temperature are normal.

f. The power should be cut off before the furnace is stopped, and the gas and water should be stopped when the furnace temperature drops below 200°C.

g. In addition to shutting down the furnace for maintenance, avoid frequent shutdowns. Frequent start and stop of the sintering furnace will cause the heating elements to be easy to age, the refractory materials are easy to break, the atmosphere in the furnace is not pure, and the furnace temperature is easy to fluctuate.