Material Grade Reference
Complete specifications for all major flange material grades with chemical composition, mechanical properties, and application guidance.
Understanding Flange Material Specifications
Flange materials are specified by ASTM standards that define chemical composition, mechanical properties, and testing requirements. Selecting the correct material grade is critical for safe, reliable system operation. Different materials have different pressure ratings, temperature capabilities, and corrosion resistance characteristics.
Material Selection Factors
- • Operating temperature range
- • Design pressure
- • Service fluid (corrosive?)
- • Thermal cycling frequency
- • System code requirements
Key Mechanical Properties
- • Tensile strength (PSI)
- • Yield strength (PSI)
- • Elongation percentage
- • Creep rate at temp
- • Impact toughness
Major Flange Material Grades
ASTM A105 - Carbon Steel
Most CommonSpecification
- Standard: ASTM A105/A105M
- Type: Carbon steel forgings
- Grade: Standard grade only
- Form: Forged, normalized
Typical Chemistry
- Carbon: 0.20-0.35%
- Manganese: 0.60-1.05%
- Silicon: 0.10-0.35%
- Phosphorus: max 0.035%
Service Range
Temperature: -20°F to 850°F | Pressure Rating: All classes (150-2500 psi)
Advantages
- ✓ Excellent cost-effectiveness
- ✓ Wide availability
- ✓ Good strength to ~800°F
- ✓ Standard for most applications
- ✓ Easy machining and welding
Applications
- • Moderate temperature steam
- • Industrial compressed air
- • Water and utility piping
- • HVAC systems
- • General industrial service
ASTM A182 - Stainless & Alloy Forgings
Corrosion ResistantCommon Grades
- F304: Austenitic stainless (Ni 8-12%, Cr 18-20%)
- F304L: Lower carbon version for corrosion
- F316: Molybdenum added (better pitting resistance)
- F316L: Lower carbon, best corrosion resistance
- F5/F9: Chromium-molybdenum alloy (high temp)
- F11/F22: Chromium-molybdenum (power plant steam)
- F91: Modified 9Cr (ultra-high temperature)
Service Characteristics
- Austenitic (F304/F316): -320°F to 800°F+
- Alloy (F5/F9): Up to 1100°F
- F11/F22: Steam service (900-1100°F)
- F91: 1200°F+ capability
F304/F304L
Chemical, food, pharma
F316/F316L
Marine, seawater, chloride
F5/F9/F11/F22
Power, steam, high-temp
F91
Ultra-high temperature
ASTM A350 - Low Temperature Forgings
CryogenicSpecification
- Common Grades: LF2, LF3, LF4, LF5, LF6, LF787
- LF2: Most common (carbon-manganese)
- LF3/LF4: Colder service
- LF787: Very low carbon
Service Range
- LF2: Down to -50°F
- LF3: Down to -150°F
- LF787: Down to -75/-100°F
- Cryogenic: Impact strength maintained at cryogenic temps
Application Examples
LNG (Liquefied Natural Gas) systems, liquid nitrogen, liquid hydrogen, cryogenic research, ethylene plants, helium transfer systems. A350 is mandatory for service below -20°F.
Note: A350 LF2 is more expensive than A105 but essential for cryogenic service. Using A105 below -20°F risks brittle fracture.
ASTM A694 - High-Strength Carbon Steel
PipelineGrades Available
- F52: 52 ksi SMYS
- F60: 60 ksi SMYS
- F65: 65 ksi SMYS
- F70: 70 ksi SMYS
Advantages
- ✓ Higher strength than A105
- ✓ Lower cost for equivalent rating
- ✓ Reduces wall thickness/weight
- ✓ Good for high-pressure pipelines
Primary Application
Oil and gas pipelines, transmission lines where high strength and cost-effectiveness are critical. Allows thinner-wall designs for weight and cost reduction.
ASTM A216 - Cast Carbon Steel
Cast FlangesSpecification
- Standard: ASTM A216/A216M
- Grade WCB: Most common (carbon steel)
- Grade WCC: Lower temp (-20°F minimum)
- Type: Investment or sand cast
Service Range
- WCB: Up to ~800°F
- WCC: -20°F to 400°F
- Limited to lower pressure classes
Advantages
- ✓ Large sizes possible
- ✓ Complex shapes
- ✓ Low cost for large
- ✓ Fast delivery
Disadvantages
- ✗ Lower toughness
- ✗ Fatigue risk
- ✗ Defect potential
- ✗ Lower pressure rating
Chemical Composition Comparison
| Material | C | Mn | Si | Cr | Ni | Mo |
|---|---|---|---|---|---|---|
| A105 Carbon | 0.20-0.35% | 0.60-1.05% | 0.10-0.35% | 0.30% max | 0.40% max | 0.12% max |
| A350 LF2 | 0.30% max | 0.60-1.35% | 0.15-0.30% | 0.30% max | 0.40% max | 0.12% max |
| A182 F304 L | 0.03% max | 2.00 max | 1.00 max | 18-20% | 8-13% | - |
| A182 F316 L | 0.03% max | 2.00 max | 1.00 max | 16-18% | 10-15% | 2-3% |
| A182 F11 CL2 & 3 | 0.10-0.20% | 0.30-0.80% | 0.50-1.00% | 0.50-1.00% | - | 0.44-0.65% |
Mechanical Properties Comparison (Room Temperature)
| Material | Tensile (psi) | Yield (psi) | Elongation % | Hardness (HB) |
|---|---|---|---|---|
| A105 Carbon | 70,000 min | 36,000 min | 22% | 187 max |
| A350 LF2 | 70,000 min | 36,000 min | 22% | 197 max |
| A182 F304 L | 70,000-75,000 | 30,000 min | 30% min | 123-217 |
| A182 F316 L | 70,000-75,000 | 30,000 min | 30% min | 123-217 |
| A182 F11 CL2 & 3 | 60,000-75,000 | 40,000-45,000 | 20% min | 143-207 |
Temperature Service Ranges
A105 Carbon Steel: -20°F to 850°F (Standard industrial, most common)
A350 LF2 (Low Temp): -50°F to 850°F (Mandatory for cryogenic below -20°F)
A182 F304/F316 (Austenitic SS): -320°F to 1500°F (Excellent low and high temp)
A182 F5/F9 (Alloy): Up to 1100°F (Power plant steam and thermal service)
A182 F11/F22: 900-1100°F continuous (Premium high-temperature creep resistance)
A182 F91: Up to 1200°F+ (Ultra-high temperature advanced alloy)
Frequently Asked Questions
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