The effect of carburizing gas medium on electric heating alloy

The effect of carburizing gas medium on electric heating alloy

The carburizing gas medium used in the carburizing treatment of steel is a strong reducing medium. Carbon participation gas can be divided into two types: endothermic and exothermic, and its composition (%) is as follows.

Gas type H2 CO CO2 N2

Endothermic type 30~40 20~30 0.1~0.5 margin

Exothermic type 10~15 5~7 5~6 margin

In addition, it also contains activated carbon and methane.

The carburizing treatment temperature is generally 900~950℃, and the surface temperature of the heating element can reach 1000~1100℃. When carburizing, the heating element should be separated from the gas medium, otherwise, the heating element will be corroded.

When parts or steel with lubricants that have not been cleaned, directly enter the furnace for heat treatment, it will also generate strong reducing gas due to the decomposition of hydrocarbons, which will corrode electric heating parts.

At high temperatures, after the electric heating element contacts the carburizing gas, the protective oxide film will be destroyed, and then the carburizing gas will penetrate into the alloy to cause a carburizing reaction. The formed carbides will cause the resistance value of the alloy to increase, the plasticity to decrease, the skin peels off, and eventually the heating element quickly fails.

The main components of the protective oxide film of electric heating alloy are: Cr2O3, NiO, Fe2O3 for nickel-chromium and nickel-chromium-iron alloys, and Al2O3, Cr2O3 for iron-chromium-aluminum alloys. These oxides have stable temperatures in the strong reduction carburizing gas. It determines the strength of the alloy's carburization resistance.

1. The wiring part is placed outside the heating layer and insulation layer, and the shell should be effectively grounded;

2. Store in a dry place.

Practical application of mica electric heating coil: 　

1. Widely used in household electric circles, such as rice cookers, microwave ovens, electronic disinfection cabinets, hair dryers, electric irons, etc.

2. It is widely used as heating parts on various machine circle equipment, such as injection molding machine, copier, printer, fax machine, etc.

3. Various industrial and agricultural heating occasions, such as mold heating, plastic machinery, and other heating and drying devices.

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