ASTM B366 UNS N10276 / WPHC276 Pipe Fitting Hastelloy C276 45 Degree LR Elbow

Hastelloy C276 Pipe Fittings ASTM B366 UNS N10276 / WPHC276 45 Degree LR Elbow

ASTM B366 UNS N10276 / WPHC276 Hastelloy C276 45° Long Radius (LR) Elbow is a factory-made, wrought nickel-alloy pipe fitting used to permanently change the direction of flow in a piping system by 45 degrees.

It is manufactured, tested, and certified in strict accordance with ASTM B366 – the standard specification covering wrought high-nickel alloy fittings for pressure piping applications. The fitting is fabricated from UNS N10276 (commonly known by the trade name Hastelloy C276), which is a Nickel-Chromium-Molybdenum (Ni-Cr-Mo) alloy with a significant addition of Tungsten (W). The grade designation WPHC276 is the specific ASTM/ASME code assigned to wrought fittings made from this particular alloy, identifying its chemical composition and mechanical property requirements.

Material Properties (Why C276?)

To understand its usage, you must know its core strengths:

• Exceptional Corrosion Resistance: Resists pitting, crevice corrosion, and stress-corrosion cracking (SCC) in both oxidizing and reducing environments.

• Chloride Resistance: Highly immune to localized attack in seawater and high-chloride brine.

• Weldability: It does not sensitize (precipitate grain-boundary carbides) during welding, meaning it can be used in the "as-welded" condition without post-weld heat treatment (PWHT).

• Thermal Stability: Resists the formation of detrimental intermetallic phases (sigma phase) during high-temperature exposures.

 
Equivalent Grades of ASTM B366 UNS N10276 / WPHC276 Pipe Fitting Hastelloy C276 45 Degree LR Elbow

 
 
Mechanical Properties of ASTM B366 UNS N10276 / WPHC276 Pipe Fitting Hastelloy C276 45 Degree LR Elbow

 
 
Chemical Composition of of ASTM B366 UNS N10276 / WPHC276 Pipe Fitting Hastelloy C276 45 Degree LR Elbow

 
Important Considerations

• Cost: Alloy C276 fittings are significantly more expensive than standard stainless steel fittings due to the high nickel, molybdenum, and chromium content.

• Counterfeits/Mislabeling: Ensure material certification (Mill Test Certificate - MTC) is provided, traceable to the heat/lot number. Positive Material Identification (PMI) testing on-site is a common verification practice.

• Machining & Welding: Requires specialized procedures. Welding should use matching or over-alloyed filler metal (e.g., ERNiCrMo-4).

• Alternative Grades: For even more severe oxidizing conditions or higher temperatures, grades like C22 (UNS N06022) or C2000 (UNS N06200) might be considered.

 
 
Applications

• Chemical Processing: Handling concentrated sulfuric acid, hydrochloric acid, acetic acid, and phosphoric acid. Used in reactor vessels, distillation columns, and heat exchanger piping.

• Flue Gas Desulfurization (FGD): In coal-fired power plants, used in scrubber systems to handle highly acidic condensates and chloride-rich slurries at moderate temperatures.

• Pulp & Paper Industry: Used in bleach plants handling chlorine dioxide (ClO₂) and sodium hypochlorite.

• Pharmaceutical & Fine Chemicals: Where product purity is critical and metal ion contamination from lesser alloys is unacceptable.

• Nuclear Fuel Processing: Resistant to radioactive fluoride and chloride salts.

• Offshore / Seawater: Used in brine piping systems and seawater cooling loops where crevice corrosion under biofouling is a severe risk.