Fechral wire is made of an alloy of chromium, iron, aluminum with the addition of silicon and manganese additives. It is used for the production of heating elements for household appliances and industrial electric furnaces. The advantage of this material is its high melting point and electrical resistivity.
Advantages and disadvantages
Fechral is considered an ideal alloy that can withstand temperatures up to 1450 degrees and has a high ohmic resistance, which remains unchanged when heated (the resistance of the wire from fechral is equal to 5.47 Ohms). Such characteristics make it possible to produce heating elements from an alloy. Fechral wire has other advantages:
- Light weight.
- Preservation of anticorrosion properties in various environments.
- High yield strength.
- Affordable price.
- Resistance to mechanical stress.
Fechral wire has disadvantages, among which is fragility, which dictates certain features of the production of small wire diameter and tape and complicates the manufacturing process. Nickel or similar additives help to eliminate this disadvantage. The use of special additives increases the cost of the alloy and products made from it.
Wire marking
The purpose of the fechral wire affects its marking:
- H - elements of heating devices.
- C - elements of resistance.
- TEN - elements of electric tubular heaters.
The diameter of the fechral wire is presented in a wide range and varies from 0.1 to 10 mm.
Production Features
Cold working technology is not applicable to the alloy due to its brittleness. The thread is drawn using energy-intensive technologies, which affects the total cost of rolled metal. Most often, fechral wire is produced by pressing or drawing. Shipment of material is carried out in coils or bays.
Modern industry is experiencing a significant need for wire made from fechral. Products have an affordable cost, good consumer properties and excellent technical characteristics. Fechral in the wire slowly but surely displaces nichrome from the market. Alloys have almost identical properties, however, the cost of fechral is largely due to the addition of aluminum, rather than expensive nickel, to its composition and the diameter of the rolled metal.
Production
Fechral wire is made by cold drawing without preheating the workpieces. This method allows to obtain a cold drawn wire, which is then subjected to annealing, which increases its softness.
The following stages of production:
- The surface is etched to remove dirt.
- The wire is wound on coils or coils.
- Finished products are marked and packaged.
- Products are shipped to the customer.
The thread is drawn using a special technology using energy-intensive and high-precision equipment, which increases the final cost of a thin wire with a diameter of up to 0.1 mm.
Nichrome or fechral?
In comparison with nichrome analogues, fechral has several advantages:
- The cost of fechral wire is several times lower.
- The characteristics of X23U5T fechral wire are better than the properties of nichrome alloys: higher electrical resistivity and low density. Such parameters make it possible to obtain a large thermal power with a small volume, which allows lowering the price of products and saving materials.
- Fechral wire is inert to sulfur and sulfur compounds, in contrast to nichrome and products from it.
Fechral properties
In comparison with other metal alloys, fechral has a lower density - not more than 7210 kg / m 3 . The metal melts at a temperature of 1,500 degrees and significantly increases in size when heated. Magnetic due to the large fraction of iron in the composition, has a coefficient of linear expansion equal to 0.000015 1 / K.
The main property that characterizes Fechral alloys and wire is an electrical resistance of 1.39 ΞΌOhm * m. Thanks to this parameter, the alloy is widely used to create various heating elements.
Fehral has certain anti-corrosion properties: it is resistant to oxidation even when exposed to sulfur compounds, which is important for the metallurgical industry.
In terms of hardness, the fechral alloy is comparable to mild steel. The parameter ranges from 20 to 25 units on the Rockwell scale. Low tensile strength - about 735 MPa - leads to a decrease in ductility. For most wire grades, the tensile elongation does not exceed 16%. The fragility of the wire is largely dependent on these properties. For this reason, fechral spirals are wound after heating the metal to 300-400 degrees.
Fechral alloy withstands high temperatures, which allows you to maintain its properties during operation up to 1400 degrees. The situation changes somewhat with temperature load, that is, turning the heater on and off. Similar stresses superimposed on the increase in metal volume and brittleness, lead to the appearance of cracks.
This reduces the operational life of fechralum by several times in conditions of cyclical changes in temperature.
Application area
Fechral wire is used in the manufacture of heating elements, resistance parts and tubular heaters. The main direction is the production of electric heating furnaces of various capacities. The grade of fechral alloy used and the diameter of the wire affect the operating temperature of the furnace.
The most heat-resistant alloy is considered to be Fechral alloy X23U5T. The maximum temperature to which a wire with a diameter of 6 mm is heated is 1400 degrees.
Fechral wire is used to produce resistive elements for electrical equipment.
Due to its properties and technological characteristics, fechral filament and wire are used in various fields of industry, gradually replacing expensive and inferior in parameters nichrome.