OXYNON FURNACE is KYK's new industrial furnace prepared to provide the answer to this question. The most common technology to lower the oxygen partial pressure is a vacuum technology, in which the inner air is mechanically removed to lower the oxygen partial pressure in the air-tight chamber. The resulting low-pressure & high- temperature atmosphere acts on the surface of the heated metal /metal oxide and effectively contribute to heat treatment processes. In a high temperature chamber of low oxygen partial pressure, metal oxides will be reduced to form metal. While a metal and its oxide coexist at a constant temperature, the oxygen partial pressure will be constant as shown in the chart of "Free energy of metal oxide formation".

Constant oxygen partial pressure can be also achieved by a non-vacuum technology which does not use mechanical vacuum technology. By supplying inert atmosphere of extremely low oxygen partial pressure into the chamber, metal oxides can also be reduced to form metal. However, conventional refractory bricks made of metal oxide will also be reduced and brake. A furnace designated to operate at high temperatures and low oxygen partial pressure cannot be built of oxide-based refractory brick.

　

The walls of the OXYNON FURNACE are made of carbon material, not conventional refractory bricks. Therefore, the inner atmosphere will not be contaminated by oxygen.
The slight oxygen or oxide remaining in the supplied inert atmosphere will react with the carbon wall of the furnace interior to form carbon monoxide. The effect of this slight carbon monoxide on the metal /metal oxide is demonstrated in the chart of "Free energy of metal oxide formation"
As carbon monoxide is formed, the carbon walls will gradually break down, however, a properly properly-designed furnace which constantly discharges residual oxygen will have a longer safer operating life.
Although both vacuum furnace and atmosphere furnace can obtain a low oxygen partial pressure, these furnaces have different effect on metal evaporation. As for a vacuum furnace, metals such as zinc and chromium, which easily evaporate at higher temperature, will leave the alloy. This phenomenon can be used for surface treatment such as deposition.
With an atmospheric pressure of inert gas with low oxygen partial pressure, evaporation of chromium will not take place in the OXYNON FURNACE.

● OXYNON FURNACE

● High temperature controlled-atmosphere furnace with no oxides used for the inner walls

OXYNON FURNACE is of a continuous tunnel design which operates with its interior filled with an inert gas. Furnaces used for continuous firing of inorganic fibers are only equipped with a long heating chamber, while a continuous furnace with belt-conveyance design can be utilized for high temperature processing of metal & ceramic with a high efficiency and low cost.。

One of the most unique features of the OXYNON FURNACE is a continuous belt made of carbon fiber reinforced carbon that can be used to convey parts in temperatures up to 2600℃. This unique, high-temperature belt conveyance has never been seen before in the high temperature industry.

Heat resistant metal belt can also be used if the processing temperature is 1120℃ or lower. The atmosphere gas filled in the furnace prevents outer air from entering into the tunnel-shaped chamber through entrance openings, and also helps to exhaust the contaminated gas discharged from the processed parts. In most cases, a high purity nitrogen is used as the atmosphere gas, while argon will be used when the parts should not be exposed to nitrogen.

For stainless steels in which chromium is functioning in the form of solid solution, heating in nitrogen will cause chromium to be nitride, giving negative effects on their corrosion resistance and magnetic property. In such case, argon must be used instead.

If iron is put directly on the carbon belt, it will react with the carbon and melt at 1152℃.
In order to avoid this, an insulating material, such as non-reacting ceramic, is needed to separate the iron and carbon. Attention should be paid to the characteristics and operating temperature of this ceramic material because it is also exposed to the risk of heat-dissociation.

　

Materials evaporated from the parts while heating could damage the safety and function of the furnace. As these materials can be mostly removed at 800℃ or below, a preliminary heating process prior to the OXYNON FURNACE is necessary in such cases.