One. Choose the main point of electric heat component

1. According to temperature: (temperature of the chamber of a stove or furnace of = of heating element temperature 100- - 200 degrees)

Average furnace temperature is less than 1000 degrees, choose NiCr, feCrAl

Furnace temperature is in 1000, 1200 degrees between, choose FeCrAl(Cr27Al7Mo2)

Furnace temperature is more than 1200 degrees, choose pure metal or metalloid

2. According to furnace structure characteristic

3. According to circumstance of heat treatment workpiece

4. Radiation efficiency is tall

5. Source is convenient

2. Component of choice electric heat should have following property

Area of tall resistor, cut is big, mechanical intensity is good, hot small, chemical function stabilizes coefficient of expansion

3. Bear of heating element surface (W) choice

1. W is bigger, life is briefer

2. The temperature inside furnace is high, when mordant atmosphere, w is taken small

3. Heating element has screen thing (furnace of car of such as stage, heating element falls in furnace motherboard) when, w is taken small

4. Inside furnace can ventilated, w is taken big (can increase hundred 30, 50)

5. Ribbon element, w is taken big (can increase hundred 30, 50)

6. The component with change difficult, w is taken small

4. Bear of alloy component surface is recommended

Material is qualitative heating element temperature (unit: Celsius)

Be less than 1000 be less than 1100 be less than 1200

OCr25Al5 1.6- - 1.8 1.2- - 1.5 0.81

Cr20Ni80 1.1 0.5- - 0.8

Cr15Ni60 0.8

CrAl7Mo2 is in 1200, 1300 degrees between when, w is taken 1.6, 1.8

5. Bullion belongs to exterior bear

W, Mo, Ta is in when be less than 1800 degrees, w is taken 10, 20W/cm2

Black lead W is less than 15, 20W/cm2

Previous:Steely industry cleanness is produced -- converter is lost can steel-making engi
Next：New technology of heat treatment of low-pressure pulse vacuum