Honesty Quality Electric Furnace SiC Silicon Carbide Heating Rods

Product Overview

Description

Honesty |Quality Electric Furnace SiC Silicon Carbide Heating Rods 

 

     The sic heating elements is a kind of non-metal high temperature electric heating element. It is made of selected super quality green silicon carbide as main material,which is made into blank,silicified under high temperature and recrystallization.Compared with metal electric heating element,this kind of sic heating elements is characterized by applied in high temperature,oxidation resistance,corrosion,long life and small deformation. Therefore, it is widely used in various high temperature electric furnaces and other electric heating devices, such as in the industries of magnet,ceramics,powder metallurgy, glass, metallurgy and machinery, etc.

 

We adopt new production process of cold ends,so our sic heating elements have excellent specific rate of heat zone resistance and cold end resistance,saving energy,long life,avoiding over-temperature of cold ends to damage the furnace body.the commercial name of our sic heating elements is Honesty heating elements.

Physical property of sic heating elements

Specific gravity	2.6-2.8g/cm3	Bend strength	>300Kg
Hardness	>9MOH'S	Tendile strength	> 150Kg/cm3
Porosity rate	< 30%	Radiancy	0.85

 

  The linear expansion coefficient,heat conductivity and specific heat of sic heating elements will change along with temperature change.And the relational date are the follows.

 

Temperature	Linear expansion coefficient (10-6m/C)	Heat conductivity	Porosity rate
(C)		(Kcal/M hrC)
0	/	/	0.148
300	3.8	/	/
400	/	/	O.256
600	4.3	14-18	/
800	/	/	0.294
900	4.5	/	/
1100	/	12-16	/
1200	4.8	/	0.325
1300	/	10-14	/
1500	5.2	/	/

Chemistry property of heating elements

1.Antioxidant property of sic heating elements

  The sic heating elements start to being oxidized when heated to 800C in air;and Si02 protection film will be generated in surface of hot zone when temperature get to 1000-1300C;Cristobalite crystalized at 1300℃,at 1500℃ the protection film reaches a certain thickness which make the oxidation speed being most slowly and tends to be stable.If continuely heat to over 1627℃,the protection film will be damaged and oxidation speed will be more rapid evidently and make the sic heating elements damaged earlier.

  Though the sic heating elements will be oxidized very slowly in course of application,it also will make the resistance increased in use of a long time,this phenomenon is called ageing.In order to lower the ageing speed,we use special technology to coat a protection film on the surface of hot zone in the process of production,which enhance the antioxidant property of sic heating elements obviously and lengthen the service life.

2.The effects of alkali and alkaline metal oxide to sic heating elements

 The alkal and alkaline metal oxide will react with SiC at about 1300C and generate silicate,which is called alkali-chemical corrosion,and can influence degree of the sic heating elements glowing.

3.The effects to sic heating elements from melting metal

    Some metals,such as cobalt,nickel,chrome and so on ,can corrade the sic heating elements in hign temperature melting state and affect the service life of heating element.

 

Electric property of sic heating elements

 SiC heating elementshas rather large specific resistance. when the surface temperature of the hot zone reaches to 1050 heating in air, its resistance rate is 600~1400Ωmm2/m.Its resistance changes with the temperature rise.From room temperature to 800 is negative value,over 800 is positive characteristic curve:

 

The key factor to the optimum service life of the sic heating elements is to select the surface load of the heating element correctly  according to the furnace construction,atmosphere and temperature.Below figure shows the relation between furnace temperatures,heating element temperature and sic heating elements surface load under the condition that the heating element radiation isn't obstructed.

 

Recommended surface load:

Furnace Temperature	1100	1200	1300	1350	1400	1450
Surface load Of	<17	<13	<9	<7	<5	<4
hot zone (W/cm2)

 

U type sic heating elements

	Nominal loading(at 1050℃)
Element diameter mm	Hot zone		Cold end
	Ω/mm	W/mm	Ω/mm	W/mm
14.0	0.01360	13.19	0.00090	0.80
16.0	0.00993	15.07	0.00080	1.00
18.0	0.00732	16.98	0.00060	1.00
20.0	0.00652	18.84	0.00040	1.10
25.0	0.00432	23.55	0.00030	1.20
30.0	0.00298	28.26	0.00020	1.30
35.0	0.00271	32.97	0.00015	1.50
40.0	0.00212	37.68	0.00010	1.70
45.0	0.00114	41.82	0.00007	1.80