Molybdenum Thermal Field For Vacuum Furnace
1.Product Description of Molybdenum Thermal Field For Vacuum Furnace :
In a standard vacuum furnace with a working temperature of 1315°C, the heat shield is usually composed of two layers of molybdenum sheets on the inside and three layers of stainless steel sheets on the outside. If higher operating temperatures are required, the number of layers of molybdenum sheets and the thickness of each layer must be increased accordingly. If the working temperature exceeds 1650 ℃, tantalum sheet can be used instead of molybdenum sheet. For an all-metal thermal field, the thermal insulation performance mainly depends on the number of layers and the spacing between the metal sheets. These spacings are used to prevent heat from radiating and conducting from the central area of the thermal field to the outside. Due to the reflective properties of the molybdenum sheet, the thermal radiation emitted from the center of the thermal field is re-reflected to the workpiece located in the center of the thermal field. All-metal thermal fields are often used in environments that require high vacuum and cleanliness. For the all-metal thermal field, it should be noted that when the molybdenum metal is above 1150°C, embrittlement will occur due to the recrystallization of the metal, and the embrittled metal heat shield is easily damaged by the fixture or workpiece that falls on the screen. . Due to the high price of molybdenum metal, the cost of all-metal thermal fields is also often higher than that of thermal fields made of other materials.
2.Measurements and tolerances of Molybdenum Thermal Field For Vacuum Furnace :
Unit:mm
Produced with a single sheet of molybdenum | Produced by a sheet of several molybdenum | ||
thickness | Max cylinder diameter | Max cylinder height | |
2.0±0.1 | 450±2 | 660±1 | |
1.0±0.08 | 610±2 | 660±1 | Manufacture according to customers’ |
0.5±0.04 | 700±2 | 660±1 | requirements |
0.3±0.03 | 700±2 | 660±1 |
Customized sizes can be produced based on customer needs.
3.Physical and chemical properties of Molybdenum Thermal Field For Vacuum Furnace :
Purity:Mo≥99.95% ,99.97%
Density:Mo≥10.2g/cm3
Application temperature environment:≤2000℃;
Quantitative analysis | ||||||||||
Element | N | Mg | Fe | Cd | Ca | Bi | Si | Pb | Al | P |
Concentration(%) | 0.003 | 0.002 | 0.005 | 0.0001 | 0.002 | 0.0001 | 0.002 | 0.0001 | 0.002 | 0.001 |
Element | C | O | Ni | Sb | Sn | |||||
Concentration(%) | 0.01 | 0.003 | 0.003 | 0.0005 | 0.0001 | |||||
Purity(Metallic Base) Mo≥99.95% |
4.Manufacture process and equipment of Molybdenum Thermal Field For Vacuum Furnace :
Item | Process | Equipment | Quality check point |
1 | Mo sheet | 1 Physical and chemical properties 2 Measurements (length ,width) | |
2 | Check | 3 Surface quality | |
3 | Wound roll | Rotary machine | 1 Surface clearness |
4 | Check | 2 Diameter and height of cylinder | |
5 | Drilling, rivet | Drill press | 1 Rivet secure |
6 | Clean | Riveting machine | 2 Location of assembling hole |
7 | Check | ||
8 | Assembly | Assembly platform | 1 Surface clearness |
9 | Clean | 2 The diameter and height of cylinder conforming to the | |
10 | Check | requirements | |
11 | Package | 3 Solid assembly, and no splice among layers 4 Show certificate of quality |
5.Application of Molybdenum Thermal Field For Vacuum Furnace :
As the heat-shield parts in the sapphire growth furnace,single crystal vacuum furnace, the most decisive function of molybdenum reflection shield is to prevent and reflect the heat in the furnace. Enhancing the crystal-pulling requires heat-shield components with high density, precise measurement, smooth surface, easy assembly, and acceptable design.
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