Expanded Metal is a plate or sheet that is cut and stretched into a net.In metal and hardware processing industry, expansion alloy is often used in metal processing materials, widely used in precision measuring tools, precision instruments, electronic industry and low temperature engineering and other fields, playing an important role. Stretching metal produces a grid of diamond shaped spaces – although many other patterns can be created.
The pattern of the grid can be staggered (providing the most open area), or it can be a straight-line pattern with all rows and columns aligned. The proportion of open areas determines the amount of channel space for air, water, and light, and will vary according to the expected application of the expanded metal.
In 1896, French physicist C.E.G uialme found a wonderful alloy, the alloy in magnetic temperature near the Curie point significantly reduce the thermal expansion coefficient, in order to a wide range of temperatures near room temperature, obtain the coefficient of expansion of very small or close to zero, this kind of alloy, It is called a low expansion alloy. The composition of this alloy is 64% Fe and 36% Ni, with a face core square structure. Its brand name is 4J36.
Expanded metal is produced by an expander that converts solid metal plates and coils into expansion metal nets. The expander is equipped with a knife to determine the pattern of the grid. As the metal is fed through an expander, it is cut and stretched using both a pressurized sash and a stretch process. The gaps created by the knife allow the metal to be stretched, resulting in even holes.
Standard metal mesh：
Standard metal mesh is versatile and economical. It comes in a variety of sizes and opening sizes. It is commonly used to provide rigid,non-slip surfaces. In a standard metal mesh, the strand and connector are set at even angles. This provides additional strength and stiffness while allowing maximum air circulation.
Flat expansion metal：
A flattened sheet of metal is compressed by cold rolling a sheet of metal. Select this option when a smooth surface is required. The flattening process typically extends the length of the sheet by 5%.
Hexagonal metal mesh：
Hexagonal metal mesh has hexagonal openings instead of the usual diamond openings. The hexagon gives the metal extra strength while allowing air, light, heat, sound and liquid to pass through. Hexagonal openings are superior to diamond openings when metal expands severely.
Expansion metal for construction：
The metal mesh of the building uses a diamond pattern and adds architectural features. The result is a design that combines good aesthetics, increased security and privacy, and improved ventilation. It is suitable for functional and decorative uses, or a combination of both.
Microexpanded metal：
A microexpansion metal has a small opening in a light metal. Openings can be standard, flat, hexagonal and square. This metal mesh is usually used in filters.
Because of the high nickel content of Invar alloy and the gas resistance, corrosion resistance and wear resistance of steel are improved. Through the analysis of chemical composition, metallographic structure and mechanical and physical properties of inwa alloy, the machinability of inwa alloy is similar to that of austenitic stainless steel, but more difficult to process than austenitic stainless steel, so inwa alloy in processing mainly has the characteristics of large cutting force, tool wear fast
Invar alloy mainly in processing high has great cutting force, thus invar alloy in the machining process, a soft, sticky, and a lot of plastic, chip is not easy to break, increased the chip and the former to surface friction, this not only reduces the durability of cutters.Therefore, high performance cemented carbide coated cutting tools and new processing methods must be used to make the machining smooth, as long as the method is appropriate, it can make the difficult machining of the alloy become easy to process.
For applications where high dimensional stability is required, such as precision instruments, clocks, seismic creep meters, TV shadow cover frames, motor valves and antimagnetic watches. In land surveying, when first-order (high-precision) elevation leveling is to be carried out, the leveling stick is made of invar alloy rather than wood, fiberglass, or other metals. Some pistons use steel struts to limit their thermal expansion in the cylinder.
Low expansion alloy. Linear expansion coefficient is lower than 3×10-6 / ℃.The commonly used low expansion alloy is Invar alloy , whose average linear expansion coefficient near room temperature is 0.877×10-6 / ℃. It is mainly used to manufacture resonator, standard ruler, precision capacitor, gas laser, telescope arm and seismograph of microwave equipment.
Generally, the linear expansion coefficient of metal is inversely proportional to the melting point. The expansion and contraction caused by magnetostrictive effect of low expansion alloy below Curie point offset the thermal expansion and cold contraction effect, resulting in zero expansion or low expansion of the alloy.
The linear expansion coefficient is 4×10-6 ~ 10×10-6 / ℃. Used for sealing with ceramics, glass, silicon, mica and other objects, so it is also called sealing alloy.
The linear expansion coefficient is higher than 16×10-6 / ℃, which is mainly used as the active layer of thermal bimetal. In practice, expansion alloy only refers to low expansion alloy and constant expansion alloy.
