High Temperature Heating Elements
Introduction of Heating Elements
Heating elements are the key parts in vacuum furnace, crystal growth furnace and sapphire crystal growth furnace. The materials commonly used are Molybdenum, Tungsten, Tantalum and Molybdenum alloy. Molybdenum and Tungsten are both refractory metals. They are indispensable materials in high temperature furnaces. Molybdenum has good property of high temperature resistance, while Tungsten has better property. The melting point of Molybdenum is 2600 ℃, the density is 10.2g/cm3, and the maximum use temperature in vacuum is 1800 ℃. The melting point of Tungsten is 3400 ℃, the density is 19.6g/cm3, and the maximum use temperature in vacuum is 2400 ℃. The melting point of Tantalum is 3000 ℃, the density is 16.6g/cm3, and the maximum use temperature in vacuum is 2200 ℃.We can provide heating elements in the shape of wire, tape, sheet, rod, twisted pair and cage heater. We can produce the heating elements according to your drawings.
Distribution and functions of heating elements in the furnace
1. The heating element can ensure the temperature uniformity in the furnace. It is an important part to control the temperature uniformity.2. For medium-sized and small size furnaces, the heating elements only need to be heated from four sides.
3. The distribution length of heating elements is 1.5 to 2 times as long as that of effective heating area.
4. For the large furnace, in order to ensure the uniformity of temperature, the furnace body needs to be heated from six sides.
5. The ultra-long furnace body needs independent temperature control by sections and by multiple areas.
6. In order to prevent overheating, the distance between the elements in the hot zone and the products to be heated should generally be 50 mm to 100 mm to get the best effect.
| Resistivity of Molybdenum | |
| Temperature ℃ | Resistivity Ω·mm2/m |
| 0 | 0.045 |
| 400 | 0.076 |
| 800 | 0.176 |
| 900 | 0.278 |
| 1000 | 0.301 |
| 1100 | 0.328 |
| 1200 | 0.356 |
| 1300 | 0.385 |
| 1400 | 0.418 |
| 1500 | 0.452 |
| 1600 | 0.488 |
| 1700 | 0.525 |
| 1800 | 0.564 |
| 1900 | 0.606 |
| 2000 | 0.651 |
The Maximum Use Temperature in Vacuum
***What is the maximum use temperature in vacuum? The highest use temperature in vacuum refers to the highest surface temperature of the heating element itself. Under normal conditions, the use temperature of the heating element is about 100 ℃ higher than that in the furnace. Therefore, when designing and selecting heating elements, it is necessary to know whether the maximum use temperature can meet the requirements of the furnace environment. If the use temperature exceeds the limit, the oxidation of heating element will speed up, thus weaken its heat resistance, leading to deformation or even fracture. That will greatly reduce the service life.If you would like to purchase high temperature heating elements from China, please don't hesitate to Contact Us.
