Material Grade Guides
Material Specifications
Detailed material properties, temperature ranges, and application requirements for critical fastening solutions
ASTM A193 Grade B7
High-Strength Chromium-Molybdenum Alloy Steel
Material Composition
- Chromium-Molybdenum alloy steel
- AISI 4140, 4142, or 4145 base grades
- Heat treated (quenched and tempered)
Temperature Range
-20°F to +1000°F (-29°C to +538°C)
Optimal performance up to 750°F. Not recommended for continuous service above 1000°F.
Key Applications
- Pressure vessel flanges
- Petrochemical piping systems
- Power plant boiler components
- Refinery process equipment
- Oil and gas wellhead equipment
- High-pressure steam service
Corrosion Resistance
Moderate corrosion resistance. Requires protective coatings in corrosive environments. Galvanizing or zinc plating recommended for outdoor applications. Not suitable for marine environments without proper coating.
Industry Standards
- API 20E BSL 1, 2, and 3 compliant
- ASME B31.3 approved for process piping
- NACE MR0175/ISO 15156 compliant with restrictions
ASTM A193 Grade B8 Class 1
304 Stainless Steel - Austenitic
Material Composition
- 18% Chromium, 8% Nickel (18-8 SS)
- Type 304 Stainless Steel (UNS S30400)
- Carbide solution treated and strain hardened
Temperature Range
-425°F to +1500°F (-254°C to +816°C)
Excellent cryogenic properties. Maintains strength at elevated temperatures. No loss of ductility at low temperatures.
Key Applications
- Chemical processing equipment
- Food and beverage industry
- Pharmaceutical manufacturing
- Cryogenic applications (LNG facilities)
- High-temperature oxidizing environments
- Architectural and marine hardware
Corrosion Resistance
Excellent resistance to atmospheric corrosion. Good resistance to many organic and inorganic chemicals. Resistant to oxidation at high temperatures. Not recommended for chloride-rich environments (use B8M instead).
Special Considerations
- Non-magnetic in annealed condition
- Cannot be hardened by heat treatment
- Galling can occur - use anti-seize compound
- API 20F BSL 2 and 3 compliant
ASTM A193 Grade B7M
Chromium-Molybdenum Alloy Steel (Low Carbon)
Material Composition
- Chromium-Molybdenum alloy steel (low carbon variant)
- Maximum 0.20% Carbon (vs 0.38-0.48% for B7)
- Heat treated (quenched and tempered)
Temperature Range
-20°F to +1000°F (-29°C to +538°C)
Similar temperature range to B7. Lower carbon content improves weldability and reduces risk of hydrogen embrittlement.
Key Applications
- Welded pressure vessel flanges
- Applications requiring improved weldability
- Petrochemical piping systems
- Power plant boiler components
- Refinery process equipment
Corrosion Resistance
Similar to B7. Moderate corrosion resistance. Requires protective coatings in corrosive environments. Lower carbon content may provide slightly better resistance to hydrogen embrittlement.
Industry Standards
- API 20E BSL 1, 2, and 3 compliant
- ASME B31.3 approved for process piping
- NACE MR0175/ISO 15156 compliant with restrictions
ASTM A193 Grade B8M
316 Stainless Steel with Molybdenum
Material Composition
- 16-18% Chromium, 10-14% Nickel
- 2-3% Molybdenum (enhanced corrosion resistance)
- Type 316 Stainless Steel (UNS S31600)
Temperature Range
-425°F to +1500°F (-254°C to +816°C)
Excellent cryogenic performance. Maintains mechanical properties at high temperatures. Preferred for extreme temperature fluctuations.
Key Applications
- Marine and offshore platforms
- Subsea pipeline connections
- Desalination plants
- Chemical processing in chloride environments
- Coastal and saltwater exposure
- Pharmaceutical clean rooms
- Pulp and paper mills
Corrosion Resistance
Superior resistance to pitting and crevice corrosion. Excellent resistance to chloride stress corrosion cracking. Outstanding performance in marine and saltwater environments. Better than B8 in acidic and reducing environments.
Industry Standards
- API 20F BSL 2 and 3 compliant
- ASME B31.3 approved
- NACE MR0175/ISO 15156 compliant
- Meets ASTM F1136 requirements
ASTM A193 Grade B8 Class 1
304 Stainless Steel - Strain Hardened
Material Composition
- 18% Chromium, 8% Nickel (18-8 SS)
- Type 304 Stainless Steel (UNS S30400)
- Strain hardened (cold worked)
Temperature Range
-425°F to +1500°F (-254°C to +816°C)
Excellent cryogenic properties. Maintains strength at elevated temperatures. Standard strength level for general applications.
Key Applications
- General purpose stainless steel fasteners
- Chemical processing equipment
- Food and beverage industry
- Cryogenic applications (LNG facilities)
- High-temperature oxidizing environments
Corrosion Resistance
Excellent resistance to atmospheric corrosion. Good resistance to many organic and inorganic chemicals. Resistant to oxidation at high temperatures. Not recommended for chloride-rich environments.
ASTM A193 Grade B8 Class 2
304 Stainless Steel - High Strength
Material Composition
- 18% Chromium, 8% Nickel (18-8 SS)
- Type 304 Stainless Steel (UNS S30400)
- Heavily strain hardened (cold worked to higher strength)
Temperature Range
-425°F to +1500°F (-254°C to +816°C)
Excellent cryogenic properties. Higher strength than Class 1. Suitable for applications requiring higher mechanical properties while maintaining corrosion resistance.
Key Applications
- High-strength stainless steel fasteners
- Pressure vessel applications requiring higher strength
- Petrochemical equipment
- Cryogenic applications requiring higher strength
- Applications where Class 1 strength is insufficient
Corrosion Resistance
Similar corrosion resistance to Class 1. Excellent resistance to atmospheric corrosion. Good resistance to many organic and inorganic chemicals. Not recommended for chloride-rich environments.
ASTM A193 Grade B8M Class 2
316 Stainless Steel - High Strength
Material Composition
- 16-18% Chromium, 10-14% Nickel
- 2-3% Molybdenum (enhanced corrosion resistance)
- Type 316 Stainless Steel (UNS S31600)
- Heavily strain hardened (cold worked to higher strength)
Temperature Range
-425°F to +1500°F (-254°C to +816°C)
Excellent cryogenic performance. Higher strength than standard B8M. Combines enhanced corrosion resistance with higher mechanical properties.
Key Applications
- Marine and offshore platforms requiring higher strength
- Subsea pipeline connections
- Chemical processing in chloride environments
- Coastal installations requiring higher strength
- Applications where standard B8M strength is insufficient
Corrosion Resistance
Superior resistance to pitting and crevice corrosion. Excellent resistance to chloride stress corrosion cracking. Outstanding performance in marine and saltwater environments.
ASTM A193 Grade B16
Chromium-Molybdenum-Vanadium Alloy Steel
Material Composition
- Chromium-Molybdenum-Vanadium alloy steel
- Vanadium addition for improved high-temperature properties
- Heat treated (quenched and tempered)
Temperature Range
-20°F to +1100°F (-29°C to +593°C)
Similar to B7 but with improved high-temperature strength due to vanadium addition. Better creep resistance at elevated temperatures.
Key Applications
- High-temperature pressure vessel flanges
- Power plant applications above 1000°F
- Petrochemical processing at elevated temperatures
- Applications requiring improved creep resistance
Corrosion Resistance
Similar to B7. Moderate corrosion resistance. Requires protective coatings in corrosive environments.
ASTM A320 Grade L7
Chromium-Molybdenum Alloy Steel for Low-Temperature Service
Material Composition
- Chromium-Molybdenum alloy steel
- Similar to B7 composition
- Heat treated for low-temperature toughness
Temperature Range
-150°F to +1000°F (-101°C to +538°C)
Designed for low-temperature service. Maintains toughness at cryogenic temperatures. Suitable for LNG and cryogenic applications.
Key Applications
- Low-temperature and cryogenic service
- LNG facilities and equipment
- Refrigeration systems
- Cold storage applications
- Applications requiring low-temperature toughness
Corrosion Resistance
Similar to B7. Moderate corrosion resistance. Requires protective coatings in corrosive environments.
2205 Duplex Stainless
Two-Phase Ferritic-Austenitic Steel (UNS S32205)
Material Composition
- 22% Chromium
- 5% Nickel
- 3% Molybdenum
- Nitrogen addition (0.14-0.20%)
- ~50% ferrite, 50% austenite microstructure
Temperature Range
-50°F to +600°F (-46°C to +316°C)
Optimal performance from -50°F to +500°F. Limited use above 600°F due to sigma phase formation. Not recommended for cryogenic service.
Key Applications
- Offshore oil and gas platforms
- Subsea manifolds and piping
- Desalination equipment
- Chemical tankers and storage tanks
- Pulp and paper industry
- Heat exchangers in corrosive environments
- Marine applications with high chloride exposure
Corrosion Resistance
Exceptional resistance to chloride stress corrosion cracking. Superior pitting resistance. Excellent resistance to crevice corrosion. Outstanding performance in seawater. 20-30 times better resistance to chloride SCC than 316L.
Advantages vs. 316L Stainless
- 2x the yield strength of 316L
- Superior pitting and crevice corrosion resistance
- Better erosion resistance due to higher hardness
- More cost-effective (thinner sections possible)
Super Duplex Stainless
High-Performance Duplex (UNS S32750, S32760)
Material Composition (S32750)
- 25% Chromium
- 7% Nickel
- 4% Molybdenum
- Nitrogen addition (0.24-0.32%)
- 40-60% ferrite, balance austenite
Temperature Range
-50°F to +570°F (-46°C to +300°C)
Optimal performance range: 0°F to +480°F. Sigma phase formation limits high-temperature use. Not suitable for cryogenic applications.
Key Applications
- Deepwater subsea systems (HPHT conditions)
- Offshore platform piping in severe service
- Seawater injection systems
- Chemical process equipment with high chlorides
- Desalination plants (high-salinity environments)
- Umbilicals and flowlines (subsea oil and gas)
Corrosion Resistance
Exceptional pitting resistance (PREN ~40-42). Outstanding resistance to chloride SCC - better than all austenitic grades. Superior crevice corrosion resistance in seawater. Excellent resistance to sulfide stress cracking. Performs well in sour gas environments.
Industry Standards
- ASTM A182 F53/F55 (Super Duplex designations)
- NACE MR0175/ISO 15156 compliant for sour service
- API 6A PR2 qualified for wellhead equipment
- DNV material approval for offshore structures
ASTM A453 Grade 660
Precipitation Hardened Stainless Steel (A286)
Material Composition
- Iron-Nickel-Chromium base (UNS S66286)
- 25% Nickel, 15% Chromium, 1.25% Molybdenum
- Titanium and aluminum for age hardening
Temperature Range
-423°F to +1200°F (-253°C to +649°C)
Retains high strength up to 1200°F. Excellent creep resistance at elevated temperatures. Superior to austenitic stainless steels above 1000°F.
Key Applications
- Gas turbine components
- Jet engine fasteners
- Nuclear reactor vessels
- High-temperature petrochemical processing
- Aerospace applications
- Power generation turbine bolting
Heat Treatment
- Solution treated at 1800°F (982°C)
- Age hardened at 1325°F (718°C) for 16 hours
- Classes A, B, C, D designate heat treatment conditions
Industry Standards
- API 20E BSL 3 compliant when specified
- AMS (Aerospace Material Specification) approved
- ASME Boiler and Pressure Vessel Code approved
Inconel 718
Nickel-Chromium Superalloy (UNS N07718)
Material Composition
- 50-55% Nickel (base metal)
- 17-21% Chromium
- 4.75-5.50% Niobium + Tantalum
- 2.80-3.30% Molybdenum
- Titanium and Aluminum for strengthening
Temperature Range
-423°F to +1300°F (-253°C to +704°C)
Retains excellent strength and creep resistance up to 1300°F. Outstanding performance in thermal cycling applications. Excellent cryogenic toughness.
Key Applications
- Gas turbine engines and hot sections
- Rocket motor components
- Nuclear reactor core bolting
- Downhole oil and gas tools (HPHT wells)
- Subsea wellhead equipment in deep water
- Aerospace fasteners and structural components
- Cryogenic pressure vessels
Corrosion Resistance
Excellent resistance to oxidation and corrosion. Outstanding resistance to chloride stress corrosion cracking. Superior performance in sour gas (H2S) environments. Resistant to wide range of organic and inorganic acids.
Industry Standards
- API 20E BSL 3 and API 20F BSL 3 compliant
- AMS 5662, AMS 5663, AMS 5664 (aerospace specs)
- NACE MR0175/ISO 15156 compliant for sour service
- Nuclear grade material available (ASME SA-637)
B7 vs B7M Comparison
| Property | B7 | B7M |
|---|---|---|
| Carbon Content | 0.38-0.48% | ≤0.20% (max) |
| Tensile Strength | 125 ksi min | 125 ksi min |
| Yield Strength | 105 ksi min | 105 ksi min |
| Hardness | 19-31 HRC | 19-31 HRC |
| Weldability | Moderate (requires pre/post heat treatment) | Improved (lower carbon reduces cracking risk) |
| Hydrogen Embrittlement | Standard risk | Reduced risk (lower carbon) |
| Primary Use | General high-strength applications | Welded assemblies, improved weldability |
Key Difference: B7M has significantly lower carbon content (≤0.20% vs 0.38-0.48%), making it more suitable for welded applications and reducing the risk of hydrogen embrittlement. Mechanical properties are identical.
B8 Class 1 vs B8 Class 2 Comparison
| Property | B8 Class 1 | B8 Class 2 |
|---|---|---|
| Tensile Strength | 75 ksi min | 125 ksi min |
| Yield Strength | 30 ksi min | 100 ksi min |
| Hardness | ≤95 HRB | ≤100 HRB |
| Elongation | 30% min | 12% min |
| Processing | Strain hardened (standard) | Heavily strain hardened (cold worked) |
| Ductility | Higher (30% elongation) | Lower (12% elongation) |
| Primary Use | General purpose applications | High-strength applications requiring higher mechanical properties |
Key Difference: Class 2 provides significantly higher strength (125 ksi vs 75 ksi tensile, 100 ksi vs 30 ksi yield) through heavier cold working, but with reduced ductility. Class 1 offers better formability and is suitable for most general applications.
Chemical Composition Per ASTM A751
Chemical composition requirements for material grades per ASTM A751
| Element | B7 | B7M | B8 | B8M | B8 Class 2 | B8M Class 2 | B16 | L7 |
|---|---|---|---|---|---|---|---|---|
| Carbon (C) | 0.38-0.48% | ≤0.20% | ≤0.08% | ≤0.08% | ≤0.08% | ≤0.08% | 0.38-0.48% | 0.38-0.48% |
| Manganese (Mn) | 0.75-1.00% | 0.75-1.00% | ≤2.00% | ≤2.00% | ≤2.00% | ≤2.00% | 0.75-1.00% | 0.75-1.00% |
| Phosphorus (P) | ≤0.035% | ≤0.035% | ≤0.045% | ≤0.045% | ≤0.045% | ≤0.045% | ≤0.035% | ≤0.035% |
| Sulfur (S) | ≤0.040% | ≤0.040% | ≤0.030% | ≤0.030% | ≤0.030% | ≤0.030% | ≤0.040% | ≤0.040% |
| Silicon (Si) | 0.15-0.35% | 0.15-0.35% | ≤0.75% | ≤0.75% | ≤0.75% | ≤0.75% | 0.15-0.35% | 0.15-0.35% |
| Chromium (Cr) | 0.80-1.10% | 0.80-1.10% | 18.0-20.0% | 16.0-18.0% | 18.0-20.0% | 16.0-18.0% | 0.80-1.10% | 0.80-1.10% |
| Molybdenum (Mo) | 0.15-0.25% | 0.15-0.25% | - | 2.00-3.00% | - | 2.00-3.00% | 0.15-0.25% | 0.15-0.25% |
| Nickel (Ni) | ≤0.25% | ≤0.25% | 8.0-12.0% | 10.0-14.0% | 8.0-12.0% | 10.0-14.0% | ≤0.25% | ≤0.25% |
| Vanadium (V) | - | - | - | - | - | - | 0.15-0.25% | - |
Material Grade Comparison
Comparative overview of material grades and their key characteristics
| Grade | Material Type | Tensile Strength (ksi) | Yield Strength (ksi) | Temperature Range | Primary Applications |
|---|---|---|---|---|---|
| B7 | Cr-Mo Alloy Steel | 125 min | 105 min | -20°F to +1000°F | Pressure vessels, petrochemical, power plants |
| B7M | Cr-Mo Alloy Steel (Low C) | 125 min | 105 min | -20°F to +1000°F | Welded assemblies, improved weldability |
| B8 | 304 Stainless Steel | 75 min | 30 min | -425°F to +1500°F | Chemical processing, food industry, cryogenic |
| B8 Class 2 | 304 Stainless Steel (High Strength) | 125 min | 100 min | -425°F to +1500°F | High-strength stainless applications |
| B8M | 316 Stainless Steel | 75 min | 30 min | -425°F to +1500°F | Marine, offshore, chloride environments |
| B8M Class 2 | 316 Stainless Steel (High Strength) | 125 min | 100 min | -425°F to +1500°F | Marine/offshore requiring higher strength |
| B16 | Cr-Mo-V Alloy Steel | 125 min | 105 min | -20°F to +1100°F | High-temperature applications, improved creep resistance |
| L7 | Cr-Mo Alloy Steel (Low Temp) | 125 min | 105 min | -150°F to +1000°F | Low-temperature/cryogenic service, LNG |
| 2205 Duplex | Duplex Stainless Steel | 90 min | 65 min | -50°F to +600°F | Offshore platforms, seawater systems |
| Super Duplex | Super Duplex Stainless | 116 min | 80 min | -50°F to +570°F | Deepwater subsea, severe service |
| C276 (Hastelloy) | Nickel-Chromium-Molybdenum | 100 min | 41 min | -425°F to +2000°F | Severe corrosive environments, chemical processing |
| Grade 660 | Precipitation Hardened SS | 140 min | 95 min | -423°F to +1200°F | Gas turbines, aerospace, high-temperature |
| Inconel 718 | Nickel-Chromium Superalloy | 185 min | 150 min | -423°F to +1300°F | Extreme high-temperature, HPHT wells, aerospace |
STAY UP-TO-DATE
Subscribe for exclusive deals, product updates, and technical insights delivered directly to your inbox.
By subscribing, you agree to receive marketing communications from CycloneBolt. Your information will never be shared with third parties.
MANUFACTURING DISCLAIMER
CYCLONE BOLT DOES NOT PROVIDE ENGINEERING OR APPLICATION DESIGN SERVICES
Cyclone Bolt manufactures to customer-specified standards and requirements and does not provide engineering or application design services. All product specifications, material selections, dimensional tolerances, and application requirements must be determined and provided by the customer or a qualified engineer prior to order placement.
Cyclone Bolt assumes no responsibility for the suitability, performance, or safety of any product when used in a specific application. It is the sole responsibility of the purchaser to verify that all ordered components meet the design, load, environmental, and regulatory requirements of the intended application.
For questions about material grades, certifications, or available standards, our team is available to provide product information — not engineering guidance.