Compressed Air & Nitrogen Systems: Driving Efficiency in the Metal Industry

The metal industry encompasses a wide range of different applications and processes, including metalworking, metallurgy, metal fabrication and processing, and precision metal manufacturing. Two elements that manufacturers in this sector rely on to keep their plants up and running are compressed air and nitrogen gas! The former acts as the power behind machines and tools, while the latter is essential to improving and maintaining production processes and minimizing explosion risks. Let’s explore a few of the ways in which compressed air and gas are used in the metal industry.

Metal Industry Applications that Use Compressed Air

• Air Mixture. To cool down the slabs and/or billets after they have been shaped, medium pressure air is mixed with water and then sprayed onto the hot slab or billet. The result is a uniform and fast cooling.
• Bag Houses. Bag houses are dust collection systems that intake air through a duct system, with the bags catching the dust. Pulsing compressed air is moved through the bags periodically, which helps these to “self-clean.” The dust then goes into a hopper and is removed.
• Blast Furnaces. Iron ore, coke and limestone are combined in a blast furnace to produce iron; compressed hot air is blasted into the furnace so that it can reach the melting point.
• Coke Production. Bituminous coal is heated between 1000° and 2000° C to yield the coke byproduct. A coke plant needs continuous air supply once fired. It cannot afford loss in air supply for a period of at least 3 months.
• Instrument Air. Many applications in the production process of metals need compressed air for instrumentation purposes. Crust breaking, air nozzles, pneumatic conveying are just a few of the operations that are dependent on compressed air.
• Oxygen Furnace. Iron, steel scrap and flux are combined in the oxygen furnace to produce steel. 99% pure oxygen is then blown into the vessel with an oxygen lance. This makes the temperature rise to melt the scrap, which eventually results in liquid steel.

Metal Industry Applications that Use Nitrogen Gas

• Aluminum Degassing. Nitrogen is sparged through molten aluminum to remove impurities from the metal, which in turn helps remove to weak points from finished products.
• Heat Treating. In heat treating, nitrogen is used to create an inert environment in the furnace, meaning that it removes the oxygen and thereby helps to decrease the chance of oxidation on finished products. It can also be used to accelerate the absorption of carbon in the treated metal, prevents oxidation during the cooling stage of steel, and is used for annealing processes to prevent exothermic reactions and overheated furnaces.
• Laser Cutting. Nitrogen is the gas of choice with laser cutting applications, as it provides a flawless finish and oxidation-free cut. This is especially true with laser cutting operations working with aluminum, stainless steel, and carbon steel.
• Metal Coating. To protect again corrosion, metals are often coated with other metals and materials; nitrogen gas, used as a shielding gas, helps prevent oxidation during this process.
• Plasma Cutting. Nitrogen is used as a pierce gas in plasma cutting, which means it is used in a plasma torch to help pierce and cut through materials via a jet of hot plasma.

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