Hastelloy C276 (N10276) Spectacle Blind Flange B16.48 , ASTM B462 / ASME SB462

Overview of C276 (N10276) Spectacle Blind Flange

Hastelloy C276 Flanges are made up of the nickel chromium molybdenum alloy that is called hastelloy. The composition includes 50.99% nickel, 14.5% chromium, 15% molybdenum and carbon, manganese, silicon, sulfur, cobalt, iron and phosphorus in it. The Hastelloy C276 Flanges have high melting point of 1370 degrees Celsius. This high melting point allows for higher operating temperatures of the flanges. The material also has 790MPa minimum tensile strength and 355MPa minimum yield strength.

What Is a Spectacle Blind Flange?

A Spectacle Blind Flange (also called a figure-8 flange) is a safety device used in piping systems to either allow or block flow. It consists of two discs:

• One solid (blind) to block the flow,

• One open (spacer or ring) to allow flow.
  They're joined together like eyeglasses (hence “spectacle”) and can be rotated to either position during maintenance or shutdown.

Hastelloy C276 is a nickel-molybdenum-chromium superalloy with an addition of tungsten designed to have excellent corrosion resistance in a wide range of severe environments. The high nickel and molybdenum contents make the nickel steel alloy especially resistant to pitting and crevice corrosion in reducing environments while chromium conveys resistance to oxidizing media. The low carbon content minimizes carbide precipitation during welding to maintain corrosion resistance in as-welded structures. This nickel alloy is resistant to the formation of grain boundary precipitates in the weld heat-affected zone, thus making it suitable for most chemical process application in an as welded condition.

Although there are several variations of the Hastelloy nickel alloy, Hastelloy C-276 is by far the most widely used. It's widely used in the most severe environments such as chemical processing, pollution control, pulp and paper production, industrial and municipal waste treatment, and recovery of sour natural gas.

Equivalent Grades for Hastelloy C276 Spectacle Blind Flange

Chemical Composition of Hastelloy C276 Spectacle Blind Flange

Mechanical Properties of Hastelloy C276 Spectacle Blind Flange

Hastelloy C276 Spectacle Blind Flange Applications

• Pollution control stack liners, ducts, dampers, scrubbers, stack-gas reheaters, fans and fan housings.
• Flue gas desulfurization systems.
• Chemical processing components like heat exchangers, reaction vessels, evaporators, and transfer piping.
• Sour gas wells.
• Pulp and paper production.
• Waste treatment.
• Pharmaceutical and food processing equipment.