ASTM A105 is the most widely specified forging material for carbon steel pipe flanges in pressure piping systems worldwide. Its excellent forgeability, predictable heat treatment response, established welding procedures, and broad availability make it the default material choice for oil and gas, petrochemical, power generation, and general industrial applications. At Huaxia Steel, we forge A105 flanges in all standard types, sizes, and pressure classes with complete non-destructive examination, heat treatment, and certification.
Product Overview

Our ASTM A105 forged carbon steel flanges are produced from killed carbon steel billets heated to 1150-1250 degrees Celsius and formed on closed-die forging presses or ring rolling mills depending on flange size and geometry. After forging, all flanges undergo normalizing or quench-and-temper heat treatment to achieve the required mechanical properties and microstructure. Each flange is finish-machined on CNC lathes and machining centers to achieve precise facing, bolt hole pattern, bore tolerance, and groove geometry.
We supply flanges per ASME B16.5 for nominal pipe sizes 1/2 inch to 24 inches, and ASME B16.47 Series A and B for nominal pipe sizes 26 inches to 48 inches. Pressure classes available are 150, 300, 600, 900, 1500, and 2500 pounds. Facing options include Raised Face (RF), Flat Face (FF), Ring Type Joint (RTJ), and tongue-and-groove for special applications.
Specifications and Dimensions

| Parameter | Specification |
|---|---|
| Material Standard | ASTM A105 / ASME SA105 |
| Dimensional Standard | ASME B16.5, ASME B16.47 Series A/B |
| Size Range | NPS 1/2 inch (DN15) to NPS 48 inches (DN1200) |
| Pressure Class | Class 150, 300, 600, 900, 1500, 2500 |
| Facing Types | RF (Raised Face), FF (Flat Face), RTJ (Ring Type Joint), Tongue and Groove |
| Flange Types | Weld Neck, Slip-On, Blind, Threaded, Socket Weld, Lap Joint |
| Coating | Black varnish, rust-preventive oil, hot-dip galvanized |
Mechanical and Chemical Properties
| Property | ASTM A105 Value |
|---|---|
| Tensile Strength (minimum) | 485 MPa (70,000 psi) |
| Yield Strength (minimum) | 250 MPa (36,000 psi) |
| Elongation (minimum) | 22% |
| Hardness (maximum) | 187 HB |
| Carbon (maximum) | 0.35% |
| Manganese | 0.60-1.05% |
| Silicon | 0.10-0.35% |
| Phosphorus (maximum) | 0.035% |
| Sulfur (maximum) | 0.040% |
Manufacturing and Quality Control
Our A105 flange manufacturing follows a rigorous, documented process route from raw material to finished product:
- Billet inspection — Ultrasonic testing of raw billets to detect internal shrinkage, pipes, and non-metallic inclusions before forging.
- Hot forging — Closed-die forging at controlled temperature with minimum 3-to-1 forging ratio to consolidate grain flow and eliminate casting defects.
- Heat treatment — Normalizing at 870-920 degrees Celsius for standard service, or quench and temper for enhanced properties.
- Rough machining — Turning to near-net shape on vertical turret lathes.
- NDE testing — Ultrasonic testing of weld neck and hub sections; magnetic particle inspection of all machined surfaces.
- Final machining — CNC facing, boring, bolt hole drilling, and groove machining to ASME B16.5 dimensional tolerances.
- Dimensional verification — CMM measurement of bolt circle diameter, face runout, bore concentricity, flange thickness, and overall dimensions.
- Marking and documentation — Heat number, size, rating, standard, and mill logo permanently marked per ASME requirements.
For low-temperature service, we supply ASTM A105N normalized flanges rated for temperatures down to minus 29 degrees Celsius. For service below minus 29 degrees Celsius, we recommend upgrading to ASTM A350 LF2 or LF3 low-temperature forging grades.
Applications
- Oil and gas upstream gathering pipelines and processing facilities
- Petrochemical refineries, chemical plants, and fertilizer complexes
- Fossil fuel and nuclear power plant steam and feedwater piping
- Shipboard piping systems and offshore platform process piping
- Water treatment, desalination, and wastewater plants
- General industrial pressure piping in Class 150 through 600
Packaging and Shipping
Flanges are individually wrapped in volatile corrosion inhibitor film and packed in wooden crates or plywood boxes with separator layers to prevent facing damage. Ring Type Joint grooves are protected with plastic caps. Each shipment includes packing list, Mill Test Certificate, NDE examination reports, and dimensional inspection record. We ship FOB, CIF, or DAP worldwide with complete export documentation.
Request your A105 flange quotation today — specify flange type, nominal size, pressure class, facing, quantity, and any special requirements such as low-temperature service, sour service, or third-party inspection. Our team will confirm forging availability, heat treatment schedule, and delivery within 24 hours. Get a quote now.
Pressure-Temperature Ratings
| Class | Pressure at 38C (psig) | Pressure at 200C (psig) | Pressure at 400C (psig) |
|---|---|---|---|
| 150 | 285 | 260 | 200 |
| 300 | 740 | 675 | 515 |
| 600 | 1480 | 1350 | 1030 |
| 900 | 2220 | 2025 | 1545 |
Why Buy from Huaxia Steel?
Our forging and machining facilities are ISO 9001 certified with ASME U and U2 stamp authorization. We maintain comprehensive liability insurance and product recall coverage. Every flange is traceable to the original heat of steel, and our quality records are retained for 15 years.
Quality Assurance and Testing
Quality is not an afterthought at Huaxia Steel — it is embedded in every stage of production from raw material selection to final inspection. Our quality management system is certified to ISO 9001:2015 and audited annually by accredited certification bodies.
Key quality control steps include incoming material verification, in-process dimensional checks, non-destructive testing at critical stages, final inspection against customer specifications, and pre-shipment review of documentation completeness. Test equipment is calibrated to national standards with full traceability.
Customization and Special Requirements
Beyond standard specifications, we accommodate special requirements that make your project successful:
- Custom lengths, tolerances, and surface finishes
- Special marking, color coding, and bar coding
- Additional testing beyond standard requirements
- Third-party witness and certification
- Consolidated shipping with other materials
- Warehousing and call-off delivery programs
Our engineering team reviews every special requirement for manufacturability and provides feedback on lead time and cost impact before order confirmation.
Global Delivery and Logistics
We ship to over 60 countries across six continents. Our logistics team coordinates with major shipping lines to secure competitive freight rates and reliable vessel schedules. Container loading is supervised by our staff to ensure proper stowage, lashing, and damage prevention.
Standard delivery terms include FOB Chinese main port, CIF destination port, DAP named place, and DDP delivered duty paid. We handle all export documentation including commercial invoice, packing list, bill of lading, certificate of origin, and Mill Test Certificate. For countries requiring pre-shipment inspection, we coordinate with SGS, Intertek, or Bureau Veritas at the loading port.
Contact us today for your specific requirements. Our technical sales team is ready to assist with specification review, material selection, and project pricing. Request a quotation.
Technical Support and Engineering Services
Our technical team includes metallurgists, welding engineers, and structural specialists who support customers throughout the project lifecycle. Services include material selection guidance, weld procedure development, corrosion assessment, failure analysis, and specification review.
For large projects, we assign a dedicated project manager who coordinates production scheduling, quality planning, inspection booking, and logistics. This single point of contact simplifies communication and ensures nothing falls through the cracks.
Compliance and Certification
Our manufacturing facilities hold multiple certifications to meet global market requirements:
- ISO 9001:2015 Quality Management System
- ISO 14001:2015 Environmental Management System
- ISO 45001:2018 Occupational Health and Safety
- API Q1 Quality Management System for Oil and Gas
- CE Marking per EN 1090 for structural steel
- ASME U and U2 Stamp for pressure equipment
We maintain comprehensive product liability insurance and professional indemnity coverage. Our quality records are retained for 15 years, ensuring full traceability for the service life of your project.
Customer Success Stories
Over the past decade, we have supplied carbon steel products to major projects across five continents. Recent highlights include a 5,000-ton bridge project in Africa, a petrochemical expansion in the Middle East, a renewable energy framework in Latin America, and multiple infrastructure projects in Southeast Asia.
Our customers consistently cite three reasons for choosing Huaxia Steel: competitive mill-direct pricing that reduces material costs by 10-20%, reliable on-time delivery that keeps construction schedules on track, and responsive technical support that solves problems before they become crises.
We measure success not by tons shipped, but by projects completed successfully and relationships built for the long term. Every order, regardless of size, receives our full attention and commitment to excellence.
How to Order
Getting started is simple. Send us your technical specification or bill of materials, including grade, dimensions, quantities, standards, and delivery requirements. Our team will review for completeness, suggest alternatives if beneficial, and provide a detailed quotation within 24 hours.
For first-time customers, we offer trial orders at competitive minimum quantities to establish quality confidence before larger commitments. We accept payment by wire transfer, letter of credit, and documentary collection depending on order value and customer preference.
Contact us today to discuss your project requirements and discover why buyers worldwide trust Huaxia Steel as their carbon steel supplier. Request a quotation.
After-Sales Support and Warranty
Our commitment to customers extends beyond delivery. We provide comprehensive after-sales support including technical consultation, installation guidance, and warranty protection. All products carry a 12-month warranty against manufacturing defects, with extended warranty options available for large projects.
If you encounter any quality concerns, our quality assurance team investigates within 48 hours and provides corrective action plans. We maintain replacement stock for critical items and can expedite replacement shipments when necessary.
Our customer service team is available by email and phone during business hours across multiple time zones. For urgent technical questions, our engineers provide after-hours support to ensure your project stays on schedule.
Contact Huaxia Steel today and let our team support your next project with quality products, competitive pricing, and reliable service. Get your free quote now.





