ASTM A694 F70 Anchor Flange, API 5L X60 PSL2 Forged Pipeline Anchor Component

C&N Shipment Product Brief: 24″ BW API 6D Class 600 Anchor Flange Assembly

1. Main flange forging standard: ASTM A694 Grade F70, Butt-Weld (BW) type, API 6D compliant, Class #600, DN24
2. Matching line pipe: 24” API 5L X60 PSL2, wall thickness Ep=19.05 mm
3. Welding structure: Pipe double-sided full welded on both sides of anchor flange, effective pipe length 800 mm
4. Anti-corrosion coating system
   • Internal surface: 300 μm thick epoxy coating
   • External surface: Temporary protective coating for transit storage
5. Core function: Fixed pipeline thrust anchor, for buried long-distance high-pressure oil & gas transmission pipelines

Product Overview

An anchor flange, also known as a thrust anchor flange or fixed pipeline anchor flange, is a heavy-duty custom forged pipeline component designed to restrict axial displacement, absorb internal pressure thrust, and resist thermal expansion stress in long-distance high-pressure piping systems. Unlike standard welding neck flanges used for bolted pipe connections, the anchor flange features an integrally forged reinforced shoulder structure, which is fully butt-welded into the pipeline and embedded within concrete thrust blocks or fixed steel support structures.

As a critical safety component for process and transmission pipelines, the anchor flange transfers pipeline axial tension, internal pressure thrust, thermal cycling load, and seismic force to the foundation structure. It effectively eliminates pipeline walking, lateral deflection, and rotational displacement caused by medium pressure fluctuation, temperature variation, and ground settlement. This protection prevents overload damage to downstream valves, meters, heat exchangers, compressors, and station equipment. Anchor flanges are widely applied in buried trunk pipelines, pipeline crossing sections, riser systems, terminal boundary connections, and high-temperature/high-pressure process piping worldwide.

The assembly we recently delivered is a complete welded anchor flange unit with 800mm matched X60 PSL2 line pipe, fully conforming to API 6D valve & fitting specifications for Class 600 high-pressure pipeline service.

Common Manufacturing Materials & Application Matching

Anchor flanges are produced from 100% homogeneous forged steel blanks. Material selection is strictly matched according to operating temperature, design pressure, medium corrosivity, and burial environment, covering carbon steel, low-temperature steel, stainless steel, duplex steel, and high-performance nickel-based superalloys, fully compatible with our existing alloy product series:

Carbon & Low Alloy Steel (Normal/Low Corrosion Onshore Service)

• ASTM A105: General-purpose anchor flanges for water, steam, and conventional natural gas pipelines
• ASTM A350 LF2/LF3: Low-temperature and cryogenic pipelines for LNG and low-temperature medium transmission
• ASTM A694 F42/F52/F65/F70: High-strength large-diameter anchor flanges for long-distance oil and gas trunk lines. our recently shipped 24” Class600 anchor flange adopts Grade F70 forging standard matched with API 5L X60 PSL2 pipe.

Austenitic Stainless Steel (Weak Acid & Oxidative Corrosion)

• ASTM A182 F304/F316L: Chemical process pipelines, desalination systems, and industrial water treatment piping
• ASTM A182 F321/F347: Medium and high-temperature thermal cycling pipelines with anti-intergranular corrosion requirements
• Alloy 926 (UNS N08926): High-chloride seawater cooling systems and FGD flue gas desulfurization pipelines

Duplex & Super Duplex Steel (Chloride Rich Harsh Environment)

ASTM A182 F51/F53/F55: Offshore platform risers, coastal brine transmission pipelines, and high-chloride sewage piping with excellent pitting and SCC resistance

High-Performance Nickel-Based Alloys (Extreme High-Temperature & Corrosive Conditions)

Alloy 600 / 601 / 718 / X-750: Ultra-high-temperature furnace piping, hydrogen transmission lines, high-sulfur petrochemical pipelines, and subsea extreme-condition fixed anchoring components

Surface Protection System

Buried anchor flanges are equipped with FBE fusion bonded epoxy coating, polyurethane anti-corrosion layer, or hot-dip galvanizing treatment, cooperating with cathodic protection to achieve long-term underground anti-corrosion performance.

For this batch of 24 inch ASTM A694 F70 anchor flange assemblies, internal anti-corrosion coating is 300μm epoxy coating; external surface is equipped with temporary protective coating to avoid rust and scratch damage during sea transportation and on-site storage before installation.

Core Structural & Performance Advantages

• Integrated Reinforced Shoulder Load Structure: The thickened integral bearing shoulder adopts smooth transition design to eliminate stress concentration, evenly distributing axial thrust, shear force and bending moment. It provides stable load-bearing capacity for long-cycle alternating thermal and pressure loads.
• 100% Solid Forged Homogeneous Microstructure: Fully die-forged forming without casting porosity, shrinkage or inclusion defects. Compact grain structure ensures superior mechanical strength, fatigue resistance and structural stability compared with cast anchor parts.
• Pigging-Friendly Inner Bore Design: The inner diameter is precisely matched with the connected pipeline without step difference, supporting full-range intelligent pigging inspection and inline detection without equipment damage.
• Wide Size & Pressure Coverage: Available in sizes from NPS 1/2 to NPS 60 (DN15–DN1500), pressure classes ranging from Class 150 to Class 2500 and PN10 to PN420, covering small-bore process pipelines and large-diameter long-distance trunk lines.
• Excellent Weldability & Processability: After normalization or solution annealing stress relief treatment, anchor flanges feature low welding crack sensitivity, suitable for GTAW/GMAW on-site butt welding and integrated pipeline installation.
• Strong Environmental Adaptability: Resists thermal deformation, seismic displacement, soil corrosion and long-term static load creep, supporting customized structural optimization for special large-thrust engineering projects via FEA simulation.

Manufacturing & Inspection Standards

Anchor flange design, forging, machining and testing comply with a complete set of international mainstream pipeline, pressure vessel and oil & gas industry standards to ensure full engineering compliance:

Dimensional & Pressure Rating Standards

• ASME B16.5: Standard for small and medium diameter anchor flanges (NPS ≤24)
• ASME B16.47 Series A/B: Specification for large-diameter pipeline anchor flanges (NPS ＞24)
• MSS SP-44: Industrial standard for large-diameter transmission pipeline flanges
• EN 1092-2 & DIN 86029: European buried pipeline anchor flange engineering specifications

Pipeline Design & Load Calculation Codes

• ASME B31.4: Liquid petroleum transmission pipeline system design
• ASME B31.8: Gas transmission and distribution pipeline design
• ASME Section VIII Div.1: Pressure vessel structural strength calculation basis
• API 6A / API 17D: Onshore wellhead and subsea pipeline anchoring component standards

Material & Quality Inspection Standards

All materials comply with ASTM A105, A182, A350 series specifications. Full-batch inspections include PMI positive material identification, tensile & hardness testing, 100% UT volumetric flaw detection and MT surface crack inspection. All products are delivered with EN 10204 3.1 certified mill test reports under ISO 9001 and API Q1 quality management systems.

Main Application Fields

• Oil & Gas Long-Distance Transmission: Trunk pipeline crossing sections, station inlet/outlet fixed points, valve group anchoring positions, preventing pipeline axial creep and pressure displacement
• Offshore & Subsea Engineering: Platform riser base fixing, subsea flowline anchor sections, seawater intake and discharge pipeline anchoring components
• New Energy & Power Generation: LNG cryogenic pipelines, hydrogen transmission trunk lines, thermal power high-temperature steam piping, geothermal medium circulation systems
• Petrochemical Industry: High-temperature furnace piping, sulfur-containing and acidic corrosive medium process lines, FGD desulfurization pipeline fixed supports
• Municipal & Environmental Engineering: Urban buried natural gas pipelines, large-scale desalination piping systems, high-chloride industrial wastewater transmission lines

Standard Quality Control Workflow

All anchor flanges adopt standardized full-process quality control procedures consistent with our alloy fitting series: Raw material incoming PMI inspection → Heating & die forging forming → Heat treatment (Normalizing / Solution Annealing) → Precision CNC machining → Dimensional tolerance verification → UT/MT non-destructive testing → Mechanical performance testing → Surface blasting & anti-corrosion treatment → Laser permanent marking → Vacuum packaging.

Standard laser marking includes brand name, product type, material grade, applicable standard, pressure class, size specification, heat batch number and production serial number, achieving full traceability for international third-party inspection and procurement acceptance.

Future Industry Development Trends

• High-End Alloy Material Replacement: Driven by clean energy projects such as hydrogen transmission, offshore wind power and LNG terminals, duplex steel and nickel-based alloy anchor flanges will gradually replace conventional carbon steel products in harsh working conditions, becoming the mainstream high-value product category.
• FEA Digital Optimized Design: Finite element simulation analysis will become a standard design procedure to realize lightweight and high-strength structural optimization, reducing manufacturing cost while improving overall safety coefficient.
• Intelligent Monitoring Integration: Smart anchor flanges embedded with pressure, temperature and stress sensors are emerging, realizing real-time remote monitoring of pipeline thrust, thermal deformation and structural fatigue status, greatly improving pipeline intelligent operation and maintenance efficiency.
• Unified International Standardization: Industry organizations are accelerating the formulation of dedicated anchor flange unified design and inspection specifications, solving the current situation of scattered standard basis and promoting global standardized production and engineering application.
• Green & Low-Carbon Manufacturing Upgrade: Precision forging technology and environmentally friendly water-based anti-corrosion coatings are widely adopted to meet global carbon neutrality requirements. Advanced additive manufacturing technology shortens the delivery cycle of special large-size non-standard anchor flanges.
• Market Demand Shift to Clean Energy Infrastructure: The market growth focus is transferring from traditional fossil fuel pipelines to hydrogen energy, CCUS carbon capture, and offshore new energy supporting pipelines, driving the technical iteration of low-temperature resistant, hydrogen embrittlement resistant and high-corrosion resistant anchor flange products.

C&N can provide the customized piping products and services you need, such as prefabricated spool and anchor flanges, so contact us today for a quote.