ASTM A193 B7 Stud Bolts | High-Strength Alloy Steel Fasteners
ASTM A193 B7 stud bolts are high-strength, heat-treated alloy steel fasteners designed for high-pressure and high-temperature applications. Commonly used in oil & gas, petrochemical, refining, and power generation industries, B7 stud bolts provide excellent tensile strength, durability, and performance in demanding environments.
At RAM Threading, we manufacture and supply ASTM A193 B7 stud bolts in a wide range of sizes, thread types, and coatings—including PTFE and black oxide—to meet critical application requirements with fast turnaround and dependable quality.
Key Features
- High-strength chromium-molybdenum alloy steel (AISI 4140/4142)
- Heat-treated (quenched and tempered) for superior mechanical properties
- Designed for high-pressure and high-temperature service
- Full-length threading for maximum engagement and load distribution
- Excellent tensile strength (up to 125,000 PSI)
- Compatible with ASTM A194 Grade 2H heavy hex nuts
Applications of ASTM A193 B7 Stud Bolts
- Oil & gas refineries
- Petrochemical processing plants
- Pressure vessels and flanges
- Power generation facilities
- Heat exchangers
- Industrial piping systems
Commonly Paired With 2H Heavy Hex Nut
ASTM A193 B7 stud bolts are most commonly paired with ASTM A194 Grade 2H heavy hex nuts to create a reliable, high-strength fastening assembly for demanding applications. This combination is specifically designed to handle high-pressure and high-temperature environments, ensuring proper load distribution, secure engagement, and consistent performance in critical bolted connections.
At RAM Threading, we supply both B7 stud bolts and 2H heavy hex nuts to ensure full compatibility, helping customers achieve dependable performance across flanges, pressure vessels, and industrial piping systems.
B7 Mechanical Properties
Per ASTM A193/A193M-16
| Diameter | Tempering Temperature | Tensile Strength | Yield Strength, 0.2% offset | Elongation in 4D | Reduction of Area | Hardness |
|---|---|---|---|---|---|---|
| Min | ksi | Min ksi | Min % | Min % | Max | |
| 2 1/2″ and under | 1100°F | 125 | 105 | 16 | 50 | 321 HBW or 35 HRC |
| Over 2 1/2″ to 4″ | 1100°F | 115 | 95 | 16 | 50 | 321 HBW or 35 HRC |
| Over 4″ to 7″ | 1100°F | 100 | 75 | 18 | 50 | 321 HBW or 35 HRC |
Per ASTM A193/A193M-16
| Grade | Material | Carbon | Manganese | Phosphorus | Sulfur | Silicon | Chromium | Molybdenum |
|---|---|---|---|---|---|---|---|---|
| % by weight | % by weight | % by weight | % by weight | % by weight | % by weight | % by weight | ||
| B7 | Alloy Steel | 0.38–0.48 (1) | 0.75–1.00 | 0.035 max | 0.040 max | 0.15–0.35 | 0.80–1.10 | 0.15–0.25 |
| Standard | Description |
|---|---|
| ASTM A193 / A193M | Covers alloy steel bolting materials for high-temperature and high-pressure service, including mechanical and chemical requirements for Grade B7 stud bolts. |
| ASME B18.31.2 | Defines dimensional and general data for continuous thread and double-end stud bolts. |
| ASME B1.1 UNC & UNF Class 2A |
Specifies thread form, series, class, tolerance, and designation for unified screw threads. |
| ASTM A194 Grade 2H |
Specifies carbon and alloy steel nuts commonly used with ASTM A193 Grade B7 stud bolts (when supplied). |
| ASME B16.5 / B16.47 | Provides flange dimensional requirements and bolting guidelines for pressure-rated flanges. |
| Flange Class | Bolting | Nominal Pipe Diameter (inches) | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| 1/2 | 3/4 | 1 | 1-1/4 | 1-1/2 | 2 | 2-1/2 | 3 | 3-1/2 | 4 | ||
| 150# | Number | 4 | 4 | 4 | 4 | 4 | 4 | 4 | 4 | 8 | 8 |
| Diameter | 1/2 | 1/2 | 1/2 | 1/2 | 1/2 | 5/8 | 5/8 | 5/8 | 5/8 | 5/8 | |
| Stud Bolt Length | 2-1/4 | 2-1/2 | 2-1/2 | 2-3/4 | 2-3/4 | 3-1/4 | 3-1/2 | 3-1/2 | 3-1/2 | 3-1/2 | |
| Mach Bolt Length | 2 | 2 | 2-1/4 | 2-1/4 | 2-1/2 | 2-3/4 | 3 | 3 | 3 | 3 | |
| 300# | Number | 4 | 4 | 4 | 4 | 4 | 8 | 8 | 8 | 8 | 8 |
| Diameter | 1/2 | 5/8 | 5/8 | 5/8 | 3/4 | 5/8 | 3/4 | 3/4 | 3/4 | 3/4 | |
| Stud Bolt Length | 2-1/2 | 3 | 3 | 3-1/4 | 3-1/2 | 3-1/2 | 4 | 4-1/4 | 4-1/4 | 4-1/2 | |
| Mach Bolt Length | 2-1/4 | 2-1/2 | 2-1/2 | 2-3/4 | 3 | 3 | 3-1/4 | 3-1/2 | 3-3/4 | 3-3/4 | |
| 600# | Number | 4 | 4 | 4 | 4 | 4 | 8 | 8 | 8 | 8 | 8 |
| Diameter | 1/2 | 5/8 | 5/8 | 5/8 | 3/4 | 5/8 | 3/4 | 3/4 | 7/8 | 7/8 | |
| Stud Bolt Length | 3 | 3-1/2 | 3-1/2 | 3-3/4 | 4-1/4 | 4-1/4 | 4-3/4 | 5 | 5-1/2 | 5-3/4 | |
| 900# | Number | 4 | 4 | 4 | 4 | 4 | 8 | 8 | 8 | – | 8 |
| Diameter | 3/4 | 3/4 | 7/8 | 7/8 | 1 | 7/8 | 1 | 7/8 | – | 1-1/8 | |
| Stud Bolt Length | 4-1/4 | 4-1/2 | 5 | 5 | 5-1/2 | 5-3/4 | 6-1/4 | 5-3/4 | – | 6-3/4 | |
| 1500# | Number | 4 | 4 | 4 | 4 | 4 | 8 | 8 | 8 | – | 8 |
| Diameter | 3/4 | 3/4 | 7/8 | 7/8 | 1 | 7/8 | 1 | 1-1/8 | – | 1-1/4 | |
| Stud Bolt Length | 4-1/4 | 4-1/2 | 5 | 5 | 5-1/2 | 5-3/4 | 6-1/4 | 7 | – | 7-3/4 | |
| 2500# | Number | 4 | 4 | 4 | 4 | 4 | 8 | 8 | 8 | – | 8 |
| Diameter | 3/4 | 3/4 | 7/8 | 1 | 1-1/8 | 1 | 1-1/8 | 1-1/4 | – | 1-1/2 | |
| Stud Bolt Length | 4-3/4 | 5 | 5-1/2 | 6 | 6-3/4 | 7 | 7-3/4 | 8-3/4 | – | 10 | |
| Flange Class | Bolting | Nominal Pipe Diameter (inches) | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| 5 | 6 | 8 | 10 | 12 | 14 | 16 | 18 | 20 | 24 | ||
| 150# | Number | 8 | 8 | 8 | 12 | 12 | 12 | 16 | 16 | 20 | 20 |
| Diameter | 3/4 | 3/4 | 3/4 | 7/8 | 7/8 | 1 | 1 | 1-1/8 | 1-1/8 | 1-1/4 | |
| Stud Bolt Length | 3-3/4 | 4 | 4-1/4 | 4-1/2 | 4-3/4 | 5-1/4 | 5-1/4 | 5-3/4 | 6-1/4 | 6-3/4 | |
| Mach Bolt Length | 3-1/4 | 3-1/4 | 3-1/2 | 4 | 4 | 4-1/2 | 4-1/2 | 5 | 5-1/2 | 6 | |
| 300# | Number | 8 | 12 | 12 | 16 | 16 | 20 | 20 | 24 | 24 | 24 |
| Diameter | 3/4 | 3/4 | 7/8 | 1 | 1-1/8 | 1-1/8 | 1-1/4 | 1-1/4 | 1-1/4 | 1-1/2 | |
| Stud Bolt Length | 4-3/4 | 4-3/4 | 5-1/2 | 6-1/4 | 6-3/4 | 7 | 7-1/2 | 7-3/4 | 8 | 9 | |
| Mach Bolt Length | 4-1/4 | 4-1/4 | 4-3/4 | 5-1/2 | 5-3/4 | 6-1/4 | 6-1/2 | 6-3/4 | 7-1/4 | 8 | |
| 600# | Number | 8 | 12 | 12 | 16 | 20 | 20 | 20 | 20 | 24 | 24 |
| Diameter | 1 | 1 | 1-1/8 | 1-1/4 | 1-1/4 | 1-3/8 | 1-1/2 | 1-5/8 | 1-5/8 | 1-7/8 | |
| Stud Bolt Length | 6-1/2 | 6-3/4 | 7-1/2 | 8-1/2 | 8-3/4 | 9-1/4 | 10 | 10-3/4 | 11-1/4 | 13 | |
| 900# | Number | 8 | 12 | 12 | 16 | 20 | 20 | 20 | 20 | 20 | 20 |
| Diameter | 1-1/4 | 1-1/8 | 1-3/8 | 1-3/8 | 1-3/8 | 1-1/2 | 1-5/8 | 1-7/8 | 2 | 2-1/2 | |
| Stud Bolt Length | 7-1/2 | 7-1/2 | 8-3/4 | 9-1/4 | 10 | 10-3/4 | 11-1/4 | 12-3/4 | 13-3/4 | 17-1/4 | |
| 1500# | Number | 8 | 12 | 12 | 12 | 16 | 16 | 16 | 16 | 16 | 16 |
| Diameter | 1-1/2 | 1-3/8 | 1-5/8 | 1-7/8 | 2 | 2-1/4 | 2-1/2 | 2-3/4 | 3 | 3-1/2 | |
| Stud Bolt Length | 9-3/4 | 10-1/4 | 11-1/2 | 13-1/4 | 14-3/4 | 16 | 17-1/2 | 19-1/2 | 21-1/4 | 24-1/4 | |
| 2500# | Number | 8 | 8 | 12 | 12 | 12 | – | – | – | – | – |
| Diameter | 1-3/4 | 2 | 2 | 2-1/2 | 2-3/4 | – | – | – | – | – | |
| Stud Bolt Length | 11-3/4 | 13-1/2 | 15 | 19-1/4 | 21-1/4 | – | – | – | – | – | |
Coating & Finish Options
ASTM A193 B7 stud bolts are available in a range of coatings to meet different environmental and performance requirements. Selecting the right finish helps improve corrosion resistance, reduce installation issues, and extend service life.
- Plain Finish – standard for general applications
- Black Oxide – light corrosion resistance
- PTFE Coated – ideal for corrosive environments and reduces galling
Plain Finish B7 Stud Bolts
Plain finish ASTM A193 B7 stud bolts are supplied without any additional coating, making them a reliable and cost-effective option for general-purpose industrial applications. Commonly used in controlled or non-corrosive environments, plain B7 studs provide the full strength and performance of heat-treated alloy steel without the added cost of surface treatments.
Because there is no coating layer, plain finish stud bolts maintain precise thread dimensions, allowing for consistent fit and proper engagement with mating components such as ASTM A194 Grade 2H heavy hex nuts. These stud bolts are widely used in oil & gas, petrochemical, and industrial applications where high strength is required and corrosion exposure is minimal.
PTFE Coated B7 Stud Bolts
PTFE-coated B7 stud bolts are designed for corrosive and demanding environments where additional protection and performance are required. The PTFE coating provides excellent resistance to chemicals, moisture, and environmental exposure, making it ideal for use in oil & gas, petrochemical, and marine applications.
In addition to corrosion resistance, PTFE coatings reduce friction during installation, helping to prevent galling and allowing for more consistent torque values. This makes PTFE-coated B7 stud bolts a preferred choice for critical bolted connections where reliability and ease of installation are essential.
Black Oxide B7 Stud Bolts
Black oxide B7 stud bolts feature a conversion coating that provides light corrosion resistance while maintaining the dimensional accuracy of the fastener. This finish is commonly used in indoor or controlled environments where minimal protection is required, and maintaining a clean, uniform appearance is important.
Because black oxide does not add thickness to the stud bolt, it allows for smooth thread engagement and consistent installation without affecting fit. ASTM A193 B7 black oxide stud bolts are a cost-effective solution for applications where strength and precision are critical, but exposure to harsh environmental conditions is limited.
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