Hastelloy C276 Flanges 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.