Flange Types
Chrome Flanges
Chrome-moly alloy flanges for high-temperature refinery and power generation service.
Chrome flanges (chrome-moly or Cr-Mo alloy steel flanges) are manufactured from chromium-molybdenum alloys per ASTM A182. The chromium content provides oxidation and sulfidation resistance at elevated temperatures, while molybdenum enhances creep strength and resistance to hydrogen attack. These flanges are essential in high-temperature piping circuits where carbon steel would lose strength or suffer hydrogen damage.
The most widely specified chrome-moly grades include F5 (5Cr-0.5Mo), F9 (9Cr-1Mo), F11 (1.25Cr-0.5Mo), F22 (2.25Cr-1Mo), and F91 (9Cr-1Mo-V-Nb modified). F11 and F22 are the workhorses of refinery heater outlet piping and reactor loops. F91 is used in advanced power generation and supercritical steam applications where its superior creep strength allows lighter wall designs at temperatures up to 1100F.
Flanges.AI stocks and supplies chrome-moly flanges in all standard types and sizes per ASME B16.5 and B16.47, in pressure classes from 150 through 2500. All chrome alloy flanges include full material test reports with chemical analysis, mechanical testing, and heat treatment documentation. Post-weld heat treatment (PWHT) requirements and preheat procedures are critical for chrome-moly alloys. Contact us for pricing and availability.
