A105 Carbon Steel Flanges

High Strength and Reliability: Tensile strength ≥485 MPa, yield strength ≥250 MPa, providing reliable performance in high-pressure piping systems up to 450°C (850°F).

Excellent Weldability: Low carbon equivalent (CE) and controlled chemistry ensure excellent weldability for field and shop fabrication.

Wide Temperature Range: Service temperatures from -29°C (-20°F) up to 427°C (800°F) for standard A105; low-temperature impact testing available for service below -29°C.

Cost-Effective Solution: Most economical flange material for general industrial applications where stainless steel or alloy grades are not required.

Full Range of Types: Weld neck (WN), slip-on (SO), blind (BL), socket weld (SW), threaded (TH), lap joint (LJ), plate flanges, reducing flanges, long weld neck (LWN), and orifice flanges.

Pressure Ratings: Available in Class 150, 300, 400, 600, 900, 1500, and 2500 (PN6 to PN400 in metric equivalents).

Good Machinability: A105 offers excellent machinability for precision flange facing, drilling, and threading operations.

International Certifications: Flanges can be certified by ABS, BV, DNV, LR, GL, RINA, CCS, KR, and NK, and comply with ASME, PED, NACE (limited), and EN standards.

These standards ensure that our A105 carbon steel flanges meet global requirements for chemical composition, mechanical properties, dimensional tolerances, and pressure-temperature ratings.

Note: Carbon equivalent (CE) limits apply per ASTM A105 (CE ≤ 0.47 for Class 1, CE ≤ 0.45 for supplementary requirement S9 for improved weldability).

Heat Treatment Condition:
A105 flanges are normally supplied in one of the following conditions:

As-Forged: For general non-critical applications.

Normalized (A105N): Heated to 890–950°C and air cooled – recommended for improved impact properties and consistent grain structure.

Normalized and Tempered (N+T): For improved toughness in low-temperature service.

Low-Temperature Service: For service below -29°C (-20°F), A350 LF2 flanges should be used. A105 can be impact tested (Charpy V-Notch) with supplementary requirements for service down to -46°C (-50°F).

Standard Dimensions: ASME B16.5 for sizes up to 24″, and ASME B16.47 Series A/B for large diameters up to 60″. EN 1092-1 dimensions available upon request.

Raw Material Selection: High-quality A105 carbon steel billets or bars from certified mills with certified chemical composition and traceability.

Cutting & Heating: Material is cut to precise weight, then induction-heated to forging temperature (1100–1250°C).

Forging: Hot forged using hydraulic presses (3000–8000 tons) or hammer forging to shape the flange blank.

Heat Treatment (Optional): Normalizing at 890–950°C followed by air cooling for improved properties.

Machining: CNC lathes and milling machines produce precise dimensions, bolt holes, and facing surfaces.

Surface Finishing: Raised face serration, flat facing, or RTJ groove machining per ASME B16.5 requirements.

Marking: Laser engraving or stamping with grade (A105/A105N), size (NPS), class, heat number, manufacturer identification, and standard.

Inspection & Testing: Dimensional check, PMI (optional), hardness test, and NDT as required.

Surface Treatment: Rust preventive oil coating or phosphate coating (upon request).

Chemical Analysis: Spectrometer verification (optional – typically by mill certificate).

Mechanical Testing: Tensile strength (≥485 MPa), yield strength (≥250 MPa), elongation (≥22%), reduction of area (≥30%), hardness (≤187 HBW).

Hardness Testing: Brinell (HBW) or Rockwell B (HRB) per ASTM A370.

Dimensional Inspection: OD, ID, bolt circle, bolt hole alignment, thickness, flatness using calibrated gauges.

Thread Inspection: NPT thread verification using GO/NO-GO gauges per ANSI B1.20.1.

NDT – Liquid Penetrant Testing (PT): Upon customer request for surface defects.

NDT – Ultrasonic Testing (UT): Upon customer request for internal flaws.

NDT – Magnetic Particle Testing (MT): Upon customer request for ferromagnetic surface defects.

Impact Testing (Charpy V-Notch): Upon customer request for low-temperature service.

Third-Party Inspection: SGS, BV, DNV, ABS, TUV, LR on customer request.

Oil & Gas Refineries: Crude oil piping flanges, refinery process piping, high-pressure hydrocarbon lines, fractionator connections, vacuum unit flanges.

Power Generation: Boiler feedwater flanges, steam line flanges, cooling water piping, turbine connections, auxiliary systems.

Petrochemical Plants: Process piping, intermediate product lines, flare header flanges, compressor station flanges.

Natural Gas Transmission: Pipeline flanges, compressor station connections, regulator station flanges, metering skid flanges.

Chemical Processing (Non-Corrosive): Solvent piping, organic chemical handling (non-corrosive), water systems, utility connections.

Industrial Manufacturing: Hydraulic system flanges, pneumatic system connections, plant utility piping.

Shipbuilding & Marine (Limited): Fuel oil systems, lubricating oil lines, cooling water systems (ABS/BV/DNV/LR certified).

Water Treatment: Industrial water distribution, raw water intake, non-potable water systems.

Pressure Vessels: Nozzle flanges, manway flanges, instrument connection flanges.

Compressed Air Systems: Compressor discharge flanges, receiver tank flanges, distribution piping.

Small flanges (≤4″): Heavy-duty cartons on pallets.
Medium flanges (6″–12″): Wooden crates or pallets with protective wrapping.
Large flanges (≥14″): Individual wooden crates or steel-framed pallets.

All shipments:

Rust preventive oil coating applied

Plastic end caps for bore protection

Bolt hole protectors (for RTJ facings)

Individual tagging: Grade (A105/A105N), size, class, heat number, standard, PO number

Waterproof shipping marks for export containers

Womic Steel's Delivery Strengths:

Ready stock: Class 150 and 300 A105 flanges in sizes 1/2″–24″ – dispatch within 24 hours.

Direct cooperation with global shipowners for competitive freight rates.

Professional loading by in-house teams.

Complete documentation including MTR, EN 10204 3.1, and inspection reports.

1. What is the difference between A105 and A105N flanges?
A105N is normalized (heat treated at 890–950°C followed by air cooling). Normalizing refines the grain structure, improves impact toughness, and ensures more consistent mechanical properties. For low-temperature service or critical applications, A105N is preferred.

2. What is the maximum temperature for A105 flanges?
Standard service to 427°C (800°F). At higher temperatures, creep strength decreases significantly. For service above 500°C, consider F11/F22 alloy steel or stainless steel.

3. Can A105 flanges be used for low-temperature service?
Standard A105 is rated to -29°C (-20°F). For service below -29°C, A350 LF2 flanges (with impact testing) or A333 Grade 6 material is recommended. A105 can be impact tested with supplementary requirements.

4. Are A105 flanges suitable for sour service (H₂S)?
Limited. A105 is not typically NACE MR0175 compliant. For sour service, A105 with hardness control (≤187 HBW maximum) and impact testing may be acceptable for some conditions, or use A350 LF2 Class 1 materials.

5. Can A105 flanges be welded to stainless steel pipe?
Yes, with appropriate filler metal (309L or 309LMo) for transition joints. The weld joint should be designed to manage differential thermal expansion.

6. What facing is standard for raised face flanges?
Serrated concentric or spiral finish, 125–250 μinch roughness, as per ASME B16.5. Smooth finish available for specialized applications.

7. Do A105 flanges require post-weld heat treatment (PWHT)?
PWHT is required for A105 flanges when welded to certain materials or for certain wall thicknesses per ASME Section VIII or B31.3. Typically required when the weld joint thickness exceeds 19mm (3/4″) or for specific service conditions.

8. What is the difference between A105 and A181 flanges?
ASTM A105 is for high-temperature service (forged carbon steel), while A181 is for general service (less stringent mechanical requirements). A105 is more common and has higher strength requirements.

Complete Product Range: Largest inventory of A105/A105N flanges in all types, sizes, and pressure classes.

Strict Quality Control: ISO 9001:2015, PED 2014/68/EU, and API Q1 certified.

Standardization: All flanges manufactured to ASME, EN, JIS, or GB standards.

Normalized Option: A105N available for improved impact properties and consistency.

Large Inventory: Over 10,000 tons in stock – instant dispatch for common sizes.

Competitive Pricing: Direct forging and machining reduces intermediate costs.

Fast Global Shipping: Reliable delivery to all major ports worldwide.

Third-Party Inspection: SGS, BV, DNV, ABS, TUV, LR available.

Tel / WhatsApp:

Victor: +86 15575100681

Jack: +86 18390957568

E-mail: info@womicstainless.com

Website: www.womicsteel.com

Contact Womic Steel today for a competitive quote on A105 carbon steel flanges. We offer certified quality, fast production lead times, and reliable global delivery to keep your pipeline projects running smoothly.

Stock Examples (Class 150 WN RF – A105/A105N):

Stock Examples (Class 300 WN RF – A105/A105N):

Stock Examples (Class 600 and above – RTJ facing – A105):

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