Physical property of elements
Specific gravity | 2.6~2.8 g/cm3 |
Bend Stength > | 300kgs |
Hardness > | 9 MOH |
Tensile Strength > | 150kg/cm3 |
Porosity rate < | 30% |
Radiancy | 0.85 |
Chemical composition
Silicon carbide heating elements are made mostly of semiconductor carbofrax, so they have chemical stability and they are not corroded by acids. At certain temperature , howerer , the elements might be corroded seriously by alkali , alkaline, earth and oxides of metals.
ELECTRIC PROPERTY OF ELEMENTS
SIC heating elements has rather large specific resistance. When it is heated in air .The surface temperature of the hot zone reaches 1050 degree . Its resistance rate is 600~1400 ohm/mm2 .Its resistance value changes as the temperature rises. It shows a natrue curve : negative value from room-temperature to 800 degree and positive value over 800 degree.
Surface load of element
The key factor to the optimum service life of the element is to select the surface load of the element correctly according to the furnace construction, atmosphere and temperature , below figure shows the relation between furnace temperature , element temperature and element surface load under the condition that the lement radiation isn't obstructed .
recommend surface load:
Furnace temp | 1100 | 1200 | 1300 | 1350 | 1400 | 1450 |
Surface load of | <17 | <13 | <9 | < 7 | <5 | <4 |