High-Pressure Flanges for Oil & Gas
ASME B16.5 and B16.47 compliant solutions engineered for upstream, midstream, and downstream applications with NACE MR0175 sour service capability and RTJ sealing.
Engineered for Extreme Conditions
ApiFlange delivers mission-critical flanges for the world's most demanding upstream, midstream, and downstream oil and gas operations. From wellhead equipment to transmission pipelines, subsea systems to refinery operations, our high-pressure, high-temperature solutions are engineered to withstand the most extreme environments with absolute reliability. With expertise in NACE MR0175 sour service, RTJ sealing, high-alloy materials, and API compliance, we partner with operators worldwide to ensure safe, efficient hydrocarbon operations.
600-2500 psi
Full pressure range
Sour Service
NACE MR0175
RTJ Sealing
Leak-free design
API Compliant
Industry standard
ASME Standards & Pressure Classes
ApiFlange supplies flanges to ASME B16.5 (small bore) and B16.47 (large bore) standards covering the complete pressure range from 150 psi through 2500 psi. Our team ensures compatibility with existing systems and compliance with the most stringent API and international standards.
Pressure Classes (ASME B16.5)
150 psi
Temp: -20°F to 700°F
Low-pressure gathering, storage
300 psi
Temp: -20°F to 750°F
Standard transmission pipelines
600 psi
Temp: -20°F to 800°F
High-pressure transmission
900 psi
Temp: -20°F to 750°F
Subsea & deep water
1500 psi
Temp: -20°F to 700°F
Extreme high-pressure
2500 psi
Temp: -20°F to 500°F
Maximum service conditions
Compliance & Standards
- ✓ASME B16.5 - Steel Pipe Flanges
- ✓ASME B16.47 - Large Diameter Steel Flanges
- ✓API 6A - Wellhead Equipment
- ✓API 605 - Large Diameter Carbon Steel Flanges
- ✓NACE MR0175 - Sour Service Materials
- ✓API 579 - Fitness-for-Service
- ✓ISO 6162 - Ports and Stud Holes
- ✓ASTM Standards - Material Certification
Flanges by Application Segment
Upstream
TYPICAL APPLICATIONS
- •Wellhead equipment
- •Subsea trees and manifolds
- •Production risers
- •Control line assemblies
- •Export headers
- •Mud system connections
Materials: Carbon steel, alloy steel, duplex, super duplex
Midstream
TYPICAL APPLICATIONS
- •Main transmission pipelines
- •Compressor stations
- •Pig launcher/receiver
- •Meter stations
- •Valve manifolds
- •Blowdown systems
Materials: Carbon steel, API Grade B, Grade X series
Downstream
TYPICAL APPLICATIONS
- •Refinery piping
- •Crude charge heaters
- •Fractionation columns
- •Cooler connections
- •Product headers
- •Tank connections
Materials: Carbon steel, stainless, alloy steels, clad
Flange Types & Face Designations
Oil and gas applications demand precision engineering. ApiFlange provides all standard flange types with industry-specific face configurations to ensure optimal sealing and reliability.
Flange Types
Weld Neck
Premium choice, reinforced hub, preferred for high-pressure applications
Slip-On
Cost-effective, common in lower-pressure transmission systems
Blind
Pressure end caps, integral to system design
Orifice
Flow measurement, API 7 compatible
Reducing
Diameter transitions with minimal turbulence
Face Types (RTJ)
Raised Face (RF)
Standard for most applications
Ring Type Joint (RTJ)
High-pressure, zero-leakage design
Flat Face (FF)
Equipment connections, soft gasket
Large Male/Female
Subsea, specialty sealing
Octagonal RTJ
Premium offshore applications
High-Alloy Materials for Extreme Service
Temperature and corrosion resistance drive material selection in oil and gas. ApiFlange stocks premium alloys engineered for the harshest operating conditions.
Carbon & Alloy Steels
A105/A350 LF2
Temp: to 800°F | Standard carbon steel
F5 (5Cr)
Temp: to 1100°F | Elevated temperature
F11 (1¼Cr)
Temp: to 900°F | Moderate high-temperature
F22 (2¼Cr)
Temp: to 1050°F | Boiler & steam service
F91 (9Cr)
Temp: to 1100°F | High-temperature steam
Nickel & Exotic Alloys
Duplex/Super Duplex
Subsea & sour service
Inconel 625/718
Ultra-high temperature
Monel K-500
Corrosion resistance
Hastelloy C-276
Extreme chemical attack
Titanium Gr. 2/5
Deepwater applications
Sour Service (NACE MR0175)
When hydrogen sulfide is present, material selection becomes critical. NACE MR0175 certification ensures protection against sulfide stress cracking and corrosion. ApiFlange provides full compliance including material testing, heat treatment documentation, and hardness verification for every sour service component.
Sour Service Requirements
- ✓Material composition within NACE limits (min Cr, Ni, Mo percentages)
- ✓Hardness caps (typically 248 HV max for carbon steels)
- ✓Controlled heat treatment and stress relief
- ✓Full material traceability and test reports
- ✓H2S compatibility verification (NACE TM0177)
- ✓Post-weld heat treatment procedures
All ApiFlange sour service flanges include full NACE MR0175 compliance documentation and third-party verification. We maintain detailed records of heat lot compositions and testing to ensure uncompromising reliability in corrosive environments.
Sizes & Custom Engineering
From 0.5-inch instrument flanges to 60-inch+ large-bore designs, ApiFlange engineers solutions for every application. Custom configurations, specialty materials, and pressure testing are standard offerings.
Standard Sizes
½" to 60"
ASME B16.5/B16.47
Custom Sizes
Unlimited
Engineer to spec
Pressure Testing
Available
1.5x working pressure
Engineering Your Next Project?
Our oil and gas specialists can help you select the right flange size, pressure class, material, and face type for your specific application.