Bolt Hole Patterns and Dimensions in Stainless Steel Flanges Across Standards
When selecting stainless steel flanges, it is essential to consider the bolt hole patterns and their dimensions, which vary according to different standards (e.g., ASME, DIN, JIS, EN, etc.). These patterns ensure that flanges can be bolted together securely in piping systems. Here's an overview of the most common bolt hole patterns across various standards:
1. ASME B16.5 Flanges (ANSI)
Bolt Hole Pattern: The most common bolt hole pattern for ASME B16.5 flanges is the circle bolt pattern, also referred to as the Bolt Circle Diameter (BCD). The bolt circle is the diameter of the imaginary circle on which the bolt holes are evenly distributed.
Key Points:
Bolt Hole Sizes: Bolt hole sizes depend on the flange size and pressure class.
Bolt Hole Number: The number of bolt holes increases with the flange size and pressure rating.
| Flange Size (inches) | Class 150 | Class 300 | Class 600 |
|---|---|---|---|
| 1" | 4 holes | 4 holes | 4 holes |
| 2" | 4 holes | 4 holes | 4 holes |
| 6" | 6 holes | 6 holes | 6 holes |
| 12" | 8 holes | 8 holes | 8 holes |
| 24" | 12 holes | 12 holes | 12 holes |
2. DIN 2576 Flanges
DIN 2576 flanges, which are based on the German standard, also use a bolt circle pattern.
Key Points:
Bolt Hole Diameter: Varies based on flange size and pressure class.
Hole Number: Typically, 4, 6, or 8 bolt holes are used depending on flange size.
| Flange Size (mm) | Bolt Hole Diameter (mm) | Number of Holes |
|---|---|---|
| 40 | 14 | 4 |
| 100 | 18 | 4 |
| 250 | 22 | 8 |
| 400 | 24 | 8 |
| 600 | 30 | 12 |
3. JIS B2220 Flanges
JIS B2220 is the Japanese flange standard, with its own specifications for bolt hole sizes and patterns.
Key Points:
The bolt circle diameter increases with flange size, and the number of holes is usually 4, 6, 8, or 12 depending on the size.
The hole diameter is typically calculated to fit standard bolts.
| Flange Size (mm) | Bolt Hole Diameter (mm) | Number of Holes |
|---|---|---|
| 50 | 16 | 4 |
| 150 | 20 | 4 |
| 300 | 24 | 8 |
| 600 | 30 | 8 |
| 900 | 36 | 12 |
4. EN 1092-1 Flanges (European Standard)
The EN 1092-1 standard, commonly used in Europe, also defines the bolt hole patterns for various flange sizes.
Key Points:
Bolt Circle Diameter: The diameter is proportional to the flange size and pressure class.
Hole Number: It can be 4, 6, 8, 12, or more depending on the pressure class.
| Flange Size (DN) | Bolt Hole Diameter (mm) | Number of Holes |
|---|---|---|
| DN40 | 18 | 4 |
| DN100 | 22 | 4 |
| DN200 | 26 | 8 |
| DN500 | 30 | 8 |
| DN1000 | 36 | 12 |
5. GOST (Russian Standard) Flanges
The GOST standard, used in Russia, also defines its own bolt hole patterns for stainless steel flanges.
Key Points:
Bolt Circle Diameter: Defined based on the flange size and pressure class.
Hole Number: Typically, 4 or 6 holes are common for smaller flange sizes.
| Flange Size (mm) | Bolt Hole Diameter (mm) | Number of Holes |
|---|---|---|
| 50 | 16 | 4 |
| 150 | 20 | 4 |
| 400 | 24 | 8 |
| 600 | 30 | 8 |
| 1000 | 36 | 12 |
General Bolt Hole Pattern Dimensions
Here are a few typical dimensions used for bolt holes and bolt circles in stainless steel flanges across these standards:
| Flange Size | Bolt Circle Diameter (BCD) | Bolt Hole Diameter |
|---|---|---|
| 1" | 2.50" | 0.25" |
| 2" | 3.00" | 0.25" |
| 6" | 6.75" | 0.375" |
| 12" | 10.50" | 0.50" |
| 24" | 18.00" | 0.75" |
Considerations When Selecting Bolt Hole Sizes and Patterns
Pressure Rating: Higher pressure classes often require thicker flanges and larger bolt holes for strength.
Flange Size: As the flange size increases, so do the bolt circle diameter and number of bolt holes.
Flange Type: Certain types of flanges (e.g., Weld Neck) may require more bolt holes compared to others (e.g., Slip-On).
Material: The material of the flange, such as stainless steel or carbon steel, can affect the bolt hole size to maintain the integrity of the connection.
SSM Advantages in Flange Manufacturing
Custom Flange Designs: We offer tailored bolt hole patterns and dimensions based on specific requirements.
Full Range of Standards: We produce flanges in accordance with ASME, DIN, JIS, EN, and GOST standards.
High-Quality Materials: Available in 304, 316, Duplex, and more.
Quick Delivery: Fast delivery for industries like oil & gas, chemical, marine, and HVAC.
