ASTM A193 B8 Stainless Steel Stud Bolts (Class 1 & 2)
ASTM A193 B8 stud bolts are manufactured from stainless steel and are commonly used in applications requiring corrosion resistance and reliable strength. RAM Threading produces ASTM A193 Grade B8 stud bolts in a range of sizes and configurations to meet demanding industrial requirements across multiple industries.
Class 1
- 18-8 Grade Stainless
- nonmagnetic
- good corrosion resistance
- 75,000 tensile with the same material as AISI type 304.
Class 2
- Same as B8 except strain-hardened.
- This is a cold-working process which increases physical properties
- 100 to 125,000 PSI tensile
Key Features
- Corrosion-resistant stainless steel construction (304 stainless steel)
- Excellent resistance to oxidation and chemical exposure
- Designed for high-temperature service environments
- Full-length threading for maximum engagement and load distribution
- Strong tensile performance with excellent ductility
- Non-magnetic in annealed condition
- Reliable performance in corrosive and sanitary applications
- Compatible with ASTM A194 Grade 8 heavy hex nuts
Applications of ASTM A193 B8 Stud Bolts
ASTM A193 B8 stud bolts stainless steel composition makes them ideal for environments exposed to moisture, chemicals, and extreme temperatures.
Common applications include:
- Chemical processing plants
- Oil & gas and petrochemical facilities
- Marine and offshore environments
- Food processing and sanitary applications
- Power generation and heat exchangers
- Industrial piping systems and flanges
Commonly Paired With Grade 8 heavy hex nuts
ASTM A193 B8 stud bolts are typically paired with ASTM A194 Grade 8 heavy hex nuts to create a corrosion-resistant, high-performance fastening system. This combination ensures proper strength, compatibility, and durability in applications where stainless steel fasteners are required.
Grade 8 nuts are designed to match the mechanical properties and corrosion resistance of B8 stud bolts, providing reliable performance in environments exposed to moisture, chemicals, and elevated temperatures.
Per ASTM A193/A193M-16
| Material | Tensile Strength | Yield Strength (0.2% Offset) | Elongation in 4D | Reduction of Area | Hardness |
|---|---|---|---|---|---|
| Min ksi | Min ksi | Min % | Min % | Max | |
| 304 Stainless Steel | 75 | 30 | 30 | 50 | 223 HBW or 96 HRB (1) |
B8 Class 2 Mechanical
Properties
| Material | Tensile Strength | Yield Strength (0.2% Offset) | Elongation in 4D | Reduction of Area | Hardness |
|---|---|---|---|---|---|
| Min ksi | Min ksi | Min % | Min % | Max | |
| ASTM A193 B8 Class 2 | 125 | 100 | 12 | 35 | 321 HBW |
Per ASTM A193/A193M-16
| Grade | Material | Carbon | Manganese | Phosphorus | Sulfur | Silicon | Chromium | Nickel |
|---|---|---|---|---|---|---|---|---|
| % by weight | % by weight | % by weight | % by weight | % by weight | % by weight | % by weight | ||
| B8 | 304 Stainless Steel | 0.08 max | 2.00 max | 0.045 max | 0.030 max | 1.00 max | 18.0–20.0 | 8.0–11.0 |
| 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 – NOMINAL PIPE DIAMETER (1/2″–4″) | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Class | Bolting | 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 – NOMINAL PIPE DIAMETER (5″–24″) | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Class | Bolting | 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 B8 stud bolts are manufactured from 304 stainless steel, which provides inherent corrosion resistance without the need for additional coatings. However, certain finishes may be applied to enhance performance in specific environments.
Plain (Stainless Steel) Finish
B8 stud bolts are most commonly supplied in a plain finish, utilizing the natural corrosion resistance of 304 stainless steel. This makes them suitable for a wide range of indoor and outdoor applications.
PTFE Coated
PTFE-coated B8 stud bolts provide additional corrosion protection and reduce friction during installation. This helps prevent galling and allows for more consistent torque, making them ideal for chemical, marine, and high-moisture environments.
B8 vs B8M Stud Bolts – What’s the Difference?
ASTM A193 B8 and B8M stud bolts are both stainless steel fasteners designed for high-temperature and corrosive environments, but they differ in material composition and corrosion resistance. Choosing between them depends on the severity of the environment and exposure conditions.
| Feature | B8 Stud Bolts | B8M Stud Bolts |
|---|---|---|
| Material | 304 Stainless Steel | 316 Stainless Steel |
| Corrosion Resistance | Good | Superior |
| Chloride Resistance | Moderate | Excellent |
| Marine Use | Limited | Ideal |
| Cost | Lower | Higher |
Material Composition
- B8 Stud Bolts are manufactured from 304 stainless steel, offering good corrosion resistance for general industrial and atmospheric environments.
- B8M Stud Bolts are made from 316 stainless steel, which includes molybdenum for enhanced resistance to chlorides, saltwater, and aggressive chemicals.
Corrosion Resistance
- B8 (304 stainless) performs well in most environments but may be susceptible to corrosion in chloride-heavy or marine conditions.
- B8M (316 stainless) provides superior corrosion resistance, especially in saltwater, coastal, and chemical processing environments.
Typical Applications
- B8 Stud Bolts:
- General industrial use
- Chemical processing (moderate exposure)
- Food and sanitary applications
- Indoor or controlled environments
- B8M Stud Bolts:
- Marine and offshore applications
- Chemical and corrosive processing plants
- Seawater and desalination systems
- High-moisture or chloride-rich environments
Cost Consideration
- B8 stud bolts are typically more cost-effective and suitable for standard corrosion-resistant applications.
- B8M stud bolts are more expensive but provide longer service life in harsh environments, reducing maintenance and replacement costs over time.
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