vacuum tempering furnace heating process attentions

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As we all know, vacuum tempering furnace is mainly used for tool steel, die steel, high speed steel, ultra-high strength steel, titanium alloy and other materials after vacuum quenching, vacuum tempering after solution treatment, recrystallization annealing and vacuum aging of non-ferrous metals. Vacuum tempering furnace is a kind of heat treatment method developed with the development of precision machinery manufacturing, aerospace, national defense and other cutting-edge industries. Especially in recent years, with the improvement of parts performance and accuracy requirements, people pay more and more attention to the precise control of vacuum furnace. What should be paid attention to in the heating process of vacuum tempering furnace? Next, everyone will discuss this issue with the vacuum furnace manufacturer!

1. Avoid contact between heat treatment products and electric heating elements

In particular, enough copper, aluminum, zinc, tin, lead, etc. contact with the electric heating element, whether it is fine powder, molten liquid or steam, to prevent the formation of “pockmarks” on the surface of the electric heating body, reduce the cross section, and finally overheat and burn out.

2. Pay attention to the positioning and binding mode of temperature measuring contact

When testing the temperature uniformity of the furnace, attention should be paid to the positioning and binding mode of the temperature measuring contact and the distance from the heating element.

In the vacuum furnace, brush, broom, compressed air and vacuum cleaner are often used to clean the furnace and put bricks. Impurities such as oxide scale in the furnace should be prevented from falling on the electric heating elements, causing short circuit or even burning the bricks. The bottom plate, crucible, furnace and other heat-resistant steel components should be lifted and knocked to remove the oxide scale every time they are used for a period of time. If oxide scale and other impurities are not removed in time, they will melt and react with refractory brick, making furnace wire melt.

3. After the temperature of vacuum furnace rises, the furnace door cannot be opened for a long time

When the temperature is higher than 400 ℃, it shall not be cooled sharply. For the electric heating element, it is easy to cause oxidation and scaling when the temperature is high and the temperature changes greatly. For the molybdenum furnace, EI should be cooled to below 200 ℃ before the protective gas is stopped.

4. Make sure that the lead out bar and clamp are in good contact

The lead out bar shall not be red, and the maximum temperature rise of the clamp shall not exceed 60 ℃ during power supply. It should be noted that due to the thermal expansion, cold shrinkage and creep elongation during the heating and shutdown, the bolts of the lead out bar wiring clamp are easy to be oxidized and loose, forming a virtual connection short circuit, which should be checked and tightened regularly.

The automatic control of vacuum tempering furnace has reasonable design, high degree of automation and good reliability, which can effectively ensure the efficient and safe production, give full play to PLC’s high reliability, anti-interference and convenient debugging, realize the automation of brazing process, so as to reduce the labor intensity of operators. At the same time, it solves the problems of long construction period and serious waste of resources of single chamber furnace, realizes the saving of construction period and electric energy, and has high economic and social benefits.