Material Grade Specification

Alloy Steel F11/F22 Flanges — ASTM A182 Gr. F11 / F22

Alloy steel F11/F22 flange manufacturer, Mumbai. Cr-Mo grades for high-temp steam lines up to 593°C. Class 150-2500, normalized & tempered. Quote in 30 min.

Material Specification & Overview

Chromium-Molybdenum alloy steel flanges in ASTM A182 Grade F11 (1.25Cr-0.5Mo) and F22 (2.25Cr-1Mo) are engineered for elevated-temperature steam and hydroprocessing applications up to 593°C.

UNS DesignationK11572 (F11) / K21590 (F22)
Governing StandardASTM A182 / ASME SA-182 Grade F11 / F22

Chemical Composition (wt %)

Governing specification limits per ASTM / ASME standards. Actual values provided on EN 10204 3.1 MTC.

ElementSpecification Limit / Composition
Chromium (Cr)1.00 - 1.50% (F11)
Molybdenum (Mo)0.44 - 0.65% (F11)
Carbon (C)0.05 - 0.20%

Mechanical Properties

PropertySpecification Limit
Yield Strength205 MPa min (Class 2)
Tensile Strength415 - 585 MPa (F11)
Service Temp RangeUp to 593°C (1,100°F)

Pressure-Temperature Rating Reference

Service TempClass 150Class 300Class 600Class 900
Ambient (-29 to 38°C)290 psi750 psi1500 psi2250 psi

Primary Industry Applications

Thermal power plant main steam lines and headers
Petroleum refinery hydrocracker and catalytic reformer units
Boiler nozzle flange connections
High-pressure high-temperature steam distribution

Forging, Heat Treatment & Quality Inspection Protocols

Forging & Thermal Processing

Flanges in Alloy Steel F11/F22 Flanges are manufactured via precision closed-die or open-die forging to establish continuous metallurgical grain flow along the flange hub and neck contour. Raw billets are heated in calibrated gas-fired furnaces under strictly controlled soak temperatures to eliminate microstructural defects.

Depending on the alloy grade, components undergo certified thermal conditioning: normalizing for carbon steels (A105N, A350 LF2), rapid water quench solution annealing at 1040°C–1120°C for stainless and duplex grades, or controlled aging for nickel superalloys. This ensures exceptional notch toughness, yield strength, and resistance to stress corrosion cracking.

Dimensional Tolerances & Certification

Final machining is executed on heavy-duty CNC turning centers to guarantee precise raised face, flat face, or ring type joint (RTJ) dimensions compliant with ASME B16.5, ASME B16.47, DIN, or EN 1092-1 standards. Gasket contact surfaces receive spiral or concentric serrations strictly controlled between 125 and 250 µin Ra.

Every production heat is issued with an EN 10204 Type 3.1 inspection certificate containing full heat chemistry, mechanical tensile test data, and Charpy impact values. Independent Third-Party Inspection (TPI) by Lloyd's, BV, DNV-GL, TÜV, and SGS is readily accommodated for global EPC and refinery contracts.

Related Products & Industry Guides

Frequently Asked Procurement Questions

Q: What heat treatment is required for F11 and F22 forged flanges?

A: Flanges are normalized and tempered (or quenched and tempered) to achieve the specified grain structure, tensile properties, and creep resistance at elevated temperatures.

Direct Factory Pricing

Get Quote in 30 Minutes for Alloy Steel F11/F22 Flanges

Written commercial offer with Mill Test Certificate guarantee.

CallWhatsApp