Wednesday, 12 December 2018

Hastelloy wire- High corrosion resistance for various chemical processing applications



Hastelloy alloys are widely used by chemical processing industries as these are corrosion resistant. These are used in the areas of solar energy, pharmaceutical, geothermal, oil and gas due to their reliable performance. Hastelloy process equipment has high localized corrosion resistance, high resistance to uniform attack and high resistance to stress corrosion cracking. This alloy is easy to weld and has excellent fabrication. Hastelloy C22 alloy is resistant to pitting and crevice corrosion. It is used to protect against corrosive FGD systems and sophisticated pharmaceutical reaction vessels. Hastelloy C276 is used as shell & tube heat exchangers and bleaching vessels. Hastelloy C2000 is highly versatile and corrosion resistant alloy. It has high resistance to uniform corrosion in oxidizing or reducing environments. It has higher resistance to stress corrosion cracking and localized corrosion as compared to Hastelloy C276.

Hastelloy alloys are used in numerous applications in various industries including petrochemical, pharmaceutical, seawater, biomass, utilities, chemical process, oil & gas, geothermal, water desalination, mining, liquefied natural gas, nuclear power and solar power. Hastelloy bar alloys are fully resistant in various environments including Acetic Acid, Acetic Anhydride, Potassium Iodide, Potassium Nitrate, Potassium Oxalate, Potassium Permanganate, Potassium Sulfate, Pyrogallic Acid, Acetic Vapors, Fatty Acids, Ferric Chloride, Ferric Hydroxide, Ferric Nitrate, Ferric Sulfate, Ferrous Ammonium Citrate, Aluminum Acetate and Aluminum Chloride to name a few.

Oxidized Hastelloy X (Hx) fiber braid was demonstrated to work excellently as a good electric insulation of Ag-sheathed Bi2Sr2CaCu2O8 (Ag/Bi2212) wires. A test coil employing 45m long Ag/Bi2212 square shape wire with 50µm Hx fiber braid was fabricated in order to develop a wind-and-react processed Ag/Bi2212 superconducting magnet with a high coil current density. A test coil of size as 73mm outer diameter, 64.5mm inner diameter and 74mm coil winding height consisted of 4 layers and 210 turns and was heat-treated at around 890˚C in oxygen gas. The critical current Ic of the test coil was 245 A at 4.2 K in a self-field, corresponding to a 67% value of the short sample Ic heat-treated at the same time for comparison. Coil inductance was calculated to be 1.9mH, and as a result, the same inductance value was obtained in the test coil. It was found that Hx cloth knitting method allows to insulate sufficiently between wires in Ag/Bi2212 square shape wire.

Hastelloy is used in the manufacture of hot gas filters used to optimize the process. These filters can tolerate higher temperatures and offer greater throughput. These filters provide higher back pulse efficiency with no measurable product bleed through resulting in an optimized chemical process system. Hastelloy is also used to produce filter media made from multiple layers of woven wire mesh sintered together into a rigid, porous and durable structure. Each wire mesh layer is chosen for a specific engineering purpose that is, filtration (particle size removal), strength or flow drainage. Filter media are sintered in porous panels which are then formed and welded into strong & self-supporting filter tubes.

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