The advantages of tube:
The controllability of aural inside furnace can be guaranteed.
The control of temperature, assemble and maintainace are very convenient and can be easy to sealed.
The cubage of hearth is enlarged and throughput is improved because of no muffle pot
Strong heating ability and high efficiency
The refractory steel material is save.
The material of tube:
The electrothermal alloy material that heating tube apply should be of higher resistance rate. The percent conversion of galvanothermy is high. Because the heating tube is put in the bushing, the process of heat transmission is different from that of open type heating element. Its heat shield is big. The temperature of element must be controlled at the course of temperature rise, to avoid temperature excursion of element.
When the heater tube is closed and heated, the surface temperature of heating element is higher roughly than temperature of hearth by 100 C~150 C. So temperature of furnace and atmosphere of temperature of furnace are needed to analysed. Choose correct heating material.
The heater tube produced by gongtao company often apply Cr20Ni80, Cr25A15, Cr21A16Nb, Cr27A17Mo2 ect.
| Item |
Cr |
Ni |
AI |
Mn |
P |
S |
C |
Fe |
| Cr20Ni80 |
20-23 |
margin |
≤0.5 |
≤0.6 |
≤0.02 |
≤0.02 |
≤0.08 |
≤1.0 |
| Cr25A15 |
23-26 |
≤0.06 |
4-7 |
≤0.07 |
≤0.02 |
≤0.02 |
≤0.06 |
margin |
| Cr21A16Nb |
21-23 |
≤0.06 |
5-7 |
≤0.07 |
≤0.02 |
≤0.02 |
≤0.05 |
margin |
| Cr27A17Mo2 |
26-28 |
≤0.06 |
5-7 |
≤0.02 |
≤0.02 |
≤0.02 |
≤0.05 |
margin |
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