ASTM A182 – Forged or Rolled Alloy and Stainless Steel Pipe Flanges, Forged Fittings, and Valves and Parts for High Temperature Service Grade: F91 Chemical Requirements   max,% Elements A182 F91 Carbon 0.08-0.12 Manganese 0.30-0.60 Phosphorus 0.020 Sulfur 0.010 Silicon 0.20-0.50 Nitrogen 0.40 Chromium 8.0-9.5 Molybdenum 0.85–1.05 Columbium 0.06-0.10 Others V: 0.18-0.25 N: 0.03-0.07 Ni 0.40 Al: 0.02…