Forged Carbon Steel ASTM A105 flanges are pipe connectors made from carbon steel that meets the ASTM A105 standard. Built through precision forging, these flanges are designed to be stronger and more robust than cast material and are used in pressure piping systems for ambient and higher-temperature service. Flange dimensions, drilling, and pressure class are supplied to the standard specified on your RFQ or drawing (e.g., ASME B16.5 / ASME B16.47 / MSS SP-44). ASTM A105 flanges are commonly used in oil and gas pipelines, chemical plants, petrochemical facilities, power stations, and industrial piping systems.
A105 Flange Standards, Materials, Sizes and Variations
- Flange Types: Weld Neck, Slip On, Blind, Socket Weld, Threaded, Lap Joint
- Size Range:15 mm – 1050mm (1/2"–42") in stock. Other sizes available.
- Ratings: 150 lb–2500 lb to suit [ASME/ANSI B16.5 / ASME B16.47 / MSS SP-44]
- Facing / Sealing Type: Flat Face (FF), Raised Face (RF), Ring Joint (RTJ)
- Facing Finish: Ra 3.2um – 6.3um
- Materials: ASTM A105 / ASME SA105 (A105N available on request) Fast Delivery: Stock items same day, custom orders typically 10-20 days
- Also called: A105 Flanges, SA105 Flanges, A105N Flanges, Forged Carbon Steel Flanges, Carbon Steel Forged Flanges (low temperature versions also available)
What is A105 Flanges?
A105 flange types we supply
Our types of flanges guide explains each option in detail:
A105 flange types available:
• Weld Neck (a robust solution using a full penetration weld)
• Slip On (Can weld with internal and/or external fillet welds)
• Blind (Bolts on)
• Socket Weld (Single fillet weld on the back of the flange)
• Threaded (NPT or BSP in both taper and straight)
• Lap Joint (LJ the flange end can rotate on the pipe)
• Orifice Flanges (come in pairs for flow rate measurement)
Facing options (as specified):
• RF (Raised Face)
• FF (Flat Face)
• RTJ (Ring Type Joint)
A105 Flanges Stamping
Typically, an ASTM A105 (ASME SA105) flange will be stamped showing its size, rating, standard, material, heat number, Balcombe Engineering stamp and production and material traceability code.
Custom Packaging & Corrosion Protection and Packaging
An ASTM A105 flanges in ASME B16.5 and B16.47 will typically require protection of the sealing face(s).
Whether you want the flange protected for 2 weeks or 2 years, Balcombe Engineering have a packing system that ensures ASTM A105 flanges arrive at the installation in good condition. Our sales team are happy to provide additional information if more robust corrosion protection is required.
ASTM A105 Flanges – Special
Sometimes a specific engineering requirement may dictate the need for ASTM A105 / ASME SA105 material, a particular heat treatment condition (A105N where specified), or custom dimensions. Balcombe Engineering are a manufacturer with full ISO 9001:2015 certification and can produce to your requirements including detailed testing and documentation if required. All material is traced through the material certificate system, and ITPs, Weld Procedures and MDRs are available on request. Your order can be packaged in line with your engineering or project specifications, and we are set up to complete the tasks within remarkably short delivery time frames.
Typical applications
Commonly used in:
• Oil & gas / petrochemical piping
• Refining and hydrocarbon processing
• Power generation and general industrial pressure piping
FAQ
An A105 flange is made from ASTM A105/A105M forged carbon steel, a material specification for piping components used in pressure systems for ambient and high and/or low temperature service (including flanges, fittings, valves, and similar parts).
For many code-driven projects, the most commonly referenced “equivalent” designation is ASME SA105 (the ASME designation used in specifications and documentation for the A105 material family). Always follow the exact material callout required by your project/client documentation for compliance and traceability.
A105 is the ASTM specification designation for carbon steel forgings for piping applications—it refers to the material standard, not flange dimensions.
• ASTM A105: forged carbon steel specification for piping components such as flanges, fittings, valves, and similar parts.
• ASTM A106: specification for seamless carbon steel pipe for high-temperature service.
In many piping systems it’s normal to see A106 pipe with A105/SA105 flanges—each component is specified to the standard that matches its product form.
• ASTM A106: specification for seamless carbon steel pipe for high-temperature service.
In many piping systems it’s normal to see A106 pipe with A105/SA105 flanges—each component is specified to the standard that matches its product form.
ASTM A105 defines the material, not the flange dimensions. Flange dimensions, drilling, and pressure–temperature ratings come from the flange standard specified on your drawing/RFQ, commonly:
• ASME B16.5 (covers NPS 1/2 through NPS 24)
• ASME B16.47 (covers NPS 26 through NPS 60)
See our Flange Standards section for dimension tables:
[Link to this page: /flange-standards/ ]
• ASME B16.5 (covers NPS 1/2 through NPS 24)
• ASME B16.47 (covers NPS 26 through NPS 60)
See our Flange Standards section for dimension tables:
[Link to this page: /flange-standards/ ]
Sizes depend on the standard you’re ordering to (e.g., B16.5 vs B16.47) and the flange type. As a guide, B16.5 covers NPS 1/2–24, and B16.47 covers NPS 26–60.
A105 is a material spec—the pressure class/rating is defined by the flange standard (e.g., B16.5 / B16.47) and the selected class.
• ASME B16.5 includes pressure–temperature ratings and is commonly supplied in classes 150–2500 (per B16.5 class system).
• ASME B16.47 includes rating class designations 75, 150, 300, 400, 600, 900.
• ASME B16.5 includes pressure–temperature ratings and is commonly supplied in classes 150–2500 (per B16.5 class system).
• ASME B16.47 includes rating class designations 75, 150, 300, 400, 600, 900.
The official ASTM A105/A105M standard is published by ASTM and revisions change over time—use the current revision required by your project specifications.
A105 is used across a wide range of piping sizes—the “small vs large diameter” question is usually about the dimension standard (B16.5 vs B16.47), not the material itself. B16.5 covers smaller-to-mid sizes (up to NPS 24) and B16.47 covers large sizes (NPS 26–60).
A105N is commonly used in purchasing to indicate the part is supplied in a normalized condition. Normalizing/heat treatment requirements should follow your project specs and the governing standard requirements.
