Applications of Nickel and Iron

Nickel is a metal with many valuable properties, so it is widely used in the production of electric light sources. It can be made into a variety of products, such as nickel tubes, nickel strips, nickel foils, nickel rods, nickel wires, and nickel anodes for electrolytic cells. Nickel materials are used in large quantities as inner guide wires, brackets, Reflectors, and connecting base strips of bulb cores. Since nickel has a large secondary electron emission coefficient, nickel or nickel-plated iron is also used for cold cathodes of low-pressure discharge light sources and external leads of high-current discharge lamps. No. 08 steel (carbon content is 0.08%, commonly known as No. 08 low-carbon steel) in high-quality carbon structural steel has high strength, good plasticity and ductility, and is most widely used in the electric light source industry. The iron core wire used for winding filaments is generally made of No. 08 steel. As the core wire material, special attention should be paid to its diameter tolerance and ovality. Because the diameter tolerance and ovality are too large, they directly affect the quality of filament winding.

The lamp holder shell material used in electric light sources is often made of cold-rolled low-carbon extra-soft steel strip (QB544~80), with a tensile strength of 274.4~392N/mm and an elongation of not less than 30%. The minimum cup depth of the steel strip cupping test is 8mm. After the lamp holder is stamped with cold-rolled iron steel strip, it needs to be plated with a layer of rust-proof layer, such as zinc, nickel, copper, chromium, etc.

Because nickel reserves in my country are relatively small and relatively expensive, nickel substitutes are widely used, such as iron-plated nickel, nickel-clad steel wire, nickel-plated copper-clad iron wire, etc.

After a layer of nickel is applied to iron parts by electroplating, the surface has the properties of nickel, and nickel can be replaced in many places. This not only saves nickel, but also prevents iron from rusting, and overcomes the problem of difficult iron degassing, so it is widely used. Nickel-plated iron wire uses iron wire with a grade of HO8A as the core wire, and the coating thickness is 8~12μm. It is mainly used as the inner wire of incandescent lamps and fluorescent lamps. The cold cathode of neon lamps can also be made of nickel-plated iron material. The specifications of nickel-plated iron wire are listed in Table 3-5.

Nickel-clad steel wire is made by coating the outside of the steel wire with a layer of nickel. Because of the use of steel core wire, it has higher mechanical strength and higher melting point than nickel. In the production of electric light sources, a layer of nickel is often electroplated on the surface of 08 steel wire to make nickel-plated steel wire; it has good wear resistance, certain strength and anti-oxidation properties.