KSB Forged Alloy Steel Globe Valve Class 1500/2500/4500 — F22/F91

A182 F22 (2.25Cr-1Mo) up to 593°C and F91 (9Cr-1Mo-V) up to 650°C. Seal-welded bonnet for extreme high-pressure, high-temperature service. Up to 776 bar. Stellite 6 seats. For power plant HP/IP steam systems and supercritical boiler piping.

Alloy Steel F22/F91Class 1500, 2500, 4500NPS ¼–2 (DN 8–DN 50)

Specifications

ParameterSpecification
SeriesSICCA 1500/2500/4500 GLF
Body MaterialA182 F22 (2.25Cr-1Mo) / A182 F91 (9Cr-1Mo-V)
Pressure ClassClass 1500, 2500, 4500
Size RangeNPS ¼–2 (DN 8–DN 50)
Max Temperature650°C (1200°F) with F91
Max Pressure776 bar (11,251 psi) at Class 4500 F22
Design StandardAPI 602 (Class 1500), ASME B16.34 (Class 2500/4500)
End ConnectionsSocket Weld (ASME B16.11), Butt Weld (ASME B16.25)
Bonnet DesignSeal-welded body/bonnet joint
TrimStellite 6 hard-faced seat and disc; XM19 stem for high-temperature service
IBR CertifiedCheck with KSB
✓ Stellite Hard-Faced Seats✓ API 602 (Class 1500), ASME B16.34 (Class 2500/4500)✓ Pressure Seal / Seal Welded

Material & Applications

Why Alloy Steel F22/F91: F22 (2.25Cr-1Mo) is the workhorse alloy for high-temperature forged valves, with excellent creep resistance up to 593°C. F91 (9Cr-1Mo-V, modified) extends the temperature limit to 650°C and is specified for advanced power plant cycles where F22 reaches its creep limit. F91 also offers better thermal fatigue resistance during cycling.

Typical applications: Power plant main steam (HP), hot reheat (IP), boiler drain, and high-temperature instrument connections in supercritical and ultra-supercritical cycles. F22 for conventional high-temperature service. F91 for advanced high-efficiency power plants operating above 593°C.

Pressure/Temperature Ratings

Permissible operating pressures per ASME B16.34:

RatingPermissible Operating Pressure at Temperature
F22 — 1500-29 to 38°C: 259 bar316°C: 209 bar427°C: 175 bar593°C: 38 bar
F22 — 2500-29 to 38°C: 431 bar316°C: 348 bar427°C: 292 bar593°C: 63 bar
F22 — 4500-29 to 38°C: 776 bar316°C: 626 bar427°C: 525 bar593°C: 113 bar
F91 — 1500-29 to 38°C: 259 bar316°C: 209 bar538°C: 125 bar650°C: 50 bar
F91 — 2500-29 to 38°C: 431 bar316°C: 347 bar538°C: 209 bar650°C: 83 bar
F91 — 4500-29 to 38°C: 776 bar316°C: 625 bar538°C: 376 bar650°C: 149 bar

Alloy Steel F22/F91 Globe Valve FAQs

When should I use F91 instead of F22?
Use F91 when operating temperatures exceed 593°C, or when the piping specification calls for 9Cr-1Mo-V material. F91 is standard for supercritical (SC) and ultra-supercritical (USC) power plants where steam temperatures reach 600–650°C. At temperatures below 593°C, F22 is usually more economical.
What special welding requirements does F91 have?
F91 requires precise pre-heat (200–250°C), interpass temperature control (max 300°C), and post-weld heat treatment (PWHT at 730–770°C). Improper PWHT can create soft zones in the heat-affected zone. Ensure your welding contractor is qualified for P91 welding. KSB seal-welded bonnets are PWHT’d at the factory.
What is the maximum pressure at 600°C for F91 Class 4500?
Approximately 312 bar at 593°C and 149 bar at 650°C for Class 4500. F91 retains significantly higher strength than F22 at these temperatures. At 593°C, F91 Class 4500 rates at 376 bar vs F22 at 113 bar — more than 3x the capacity.

Need a Alloy Steel F22/F91 Globe Valve?

Specify size, class, end connection, and service conditions. Quotation within 24 hours.