Carbon Steel Forged Socket Weld Flange ASME B16.5 150# RF

1. Product Description

This specification covers forged steel flanges manufactured from high-quality killed steel via open-die or closed-die forging processes, with a minimum forging ratio (reduction ratio) of 3:1 to ensure full densification. The finished products exhibit a fine-grained microstructure with an ASTM grain size number of 5 or finer (per ASTM E112), ensuring superior toughness and resistance to brittle fracture. All flanges are fully traceable from melt shop to final inspection, with positive material identification (PMI) performed on every piece. Products are offered in conformity with ASME Section II, ASME B16.5/B16.47, and material-specific NACE MR0175/ISO 15156 requirements for sour service applications. Each flange is individually marked and supplied with comprehensive inspection documentation, including chemical analysis, mechanical test reports, and non-destructive examination records.

2. Product Applications

Forged steel flanges covered by this specification are designed for permanent installation in critical pressure-containing piping systems across the following service categories:

• General Service (Non-sour, Non-cryogenic) – Ambient to 400°C, standard carbon steel (A105) with RF face, suitable for steam, water, air, and inert gases.

• Sour Service (Wet H₂S) – Flanges shall comply with NACE MR0175/ISO 15156. Material selection limits hardness (≤22 HRC or ≤237 HB), and requires HIC (hydrogen-induced cracking) and SSC (sulfide stress cracking) resistance testing. Grades like A105N, A350 LF2, and A182 F316L are commonly selected.

• High-Temperature Service (>450°C) – Alloy steel grades (A182 F11, F22, F91) with creep-resistant properties, suitable for superheated steam and reformer lines in power plants and refineries.

• Cryogenic / Low-Temperature Service – Impact-tested materials such as A350 LF2 (tested at -46°C) or A182 F316L (tested at -196°C) for LNG, ethylene, and liquid nitrogen systems.

• High-Pressure / Critical Service – Class 1500 and 2500 RTJ flanges used in wellhead equipment, subsea manifolds, and hydrotesting circuits requiring zero leakage and high joint integrity.

3.Product Advantages

• Guaranteed Impact Toughness – Every heat lot is verified with Charpy V-notch impact tests at specified design temperatures, ensuring ductile-brittle transition performance.

• Resistance to Environmental Cracking – Controlled chemistry (low phosphorus/sulfur content) and post-forge heat treatment significantly reduce susceptibility to HIC, SSC, and stress-corrosion cracking.

• Accurate Metallurgical Structure – Normalizing, quenching-and-tempering, or solution-annealing processes ensure the optimal phase balance (ferrite-pearlite, bainite, or fully austenitic) required for each service environment.

• Superior Dimensional Stability – Post-forging CNC machining guarantees concentricity between bolt holes and bore, and exact perpendicularity of sealing faces, eliminating bolt-bending stresses during assembly.

• Full-Compliance Traceability – Chemical composition, mechanical properties, NDE results, and heat treatment cycle records are collated into a single inspection test plan (ITP) for client approval.

• Third-Party Witness Option – Manufacturing and testing can be witnessed by third-party inspection bodies (Lloyd’s, BV, SGS, TÜV) per EN 10204 Type 3.2.

4.Key Technical Parameters

FAQ

1. Are you trading company or manufacturer ? We are manufacturer ,You can see the certification.

2.How long is your delivery time? Generally it is 5-10 days if the goods are in stock. or it is 15-20 days if the goods are not in stock, it is according to quantity.

3. Do you provide samples ? is it free or extra ? Yes, we could offer the sample for free charge but need pay the cost of freight.

4. What is your terms of payment ? Payment<=1000USD, 100% in advance. Payment>=1000USD, 50% T/T in advance ,balance before shippment.