What is API 605 Flange?
API 605 flanges are essential components in piping systems and are widely used in industries such as oil and gas, petrochemical, and power generation. API 605 was a standard for large-diameter steel flanges primarily used in the petroleum and natural gas industries. These flanges were designed to accommodate large pipe sizes, usually 26 inches to 60 inches in diameter. While API 605 has been withdrawn and merged into ASME B16.47 Series B, the term is still widely used in the industry to describe these large-diameter flanges.
Features of API 605 Flange
Large-Diameter Compatibility – API 605 flanges are designed for pipe sizes ranging from 26 inches to 60 inches, making them suitable for high-volume fluid transportation.
High-Pressure Resistance – These flanges can withstand high pressures, ensuring leak-proof connections in demanding industrial applications.
Corrosion Resistance – Manufactured from high-quality carbon steel and stainless steel, API 605 flanges offer excellent resistance to corrosion and environmental damage.
Enhanced Mechanical Strength – These flanges have superior mechanical properties, providing robust support to the piping system.
Custom Machining – API 605 flanges can be customized to meet specific operational needs, ensuring compatibility with various piping configurations.
Types of API 605 Flanges
API 605 Welding Neck Flange
API 605 Threaded Flange
API 605 Socket Welding Flange
API 605 Blind Flange
API 605 Slip-on Flange
API 605 LAP Joint Flange
API 605 Flange Dimensions
| Norminal Pipe Size | O.D.of Flange, O | Min.Thick-ness of WN Flange, tf | Lenth Through Hub, Y | Diam. of Hub, X | Hub Diam. Top, A | Raised Fase Diam., R | Bore (XS) | Diam of Bolt Circle | No.of Bolt Holes | Diam.of Bolt Hole | Min.Fillet Radius, r1 | Approxi-mate Weight kgs |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 26 | 785 | 39.8 | 87 | 684 | 661.9 | 711 | 636.5 | 744.5 | 36 | 22.2 | 10 | 62.61 |
| 28 | 835 | 43 | 94 | 735 | 712.7 | 762 | 687.3 | 795.3 | 40 | 22.2 | 10 | 71.98 |
| 30 | 885 | 43 | 98 | 787 | 763.5 | 813 | 738.1 | 846.1 | 44 | 22.2 | 10 | 78 |
| 32 | 940 | 44.6 | 106 | 840 | 814.3 | 864 | 788.9 | 900.1 | 48 | 22.2 | 10 | 90.31 |
| 34 | 1005 | 47.7 | 109 | 892 | 865.1 | 921 | 839.7 | 957.3 | 40 | 25.4 | 10 | 109.16 |
| 36 | 1055 | 50.9 | 116 | 945 | 915.9 | 972 | 890.5 | 1009.6 | 44 | 25.4 | 10 | 122.69 |
| 38 | 1125 | 52.5 | 122 | 997 | 968.2 | 1022 | 942.8 | 1070 | 40 | 28.6 | 10 | 146.24 |
| 40 | 1175 | 54.1 | 127 | 1049 | 1019 | 1080 | 993.6 | 1120.8 | 44 | 28.6 | 10 | 158.37 |
| 42 | 1225 | 57.3 | 132 | 1102 | 1069.8 | 1130 | 1044.4 | 1171.6 | 48 | 28.6 | 11 | 174.09 |
| 44 | 1275 | 58.9 | 135 | 1153 | 1120.6 | 1181 | 1095.2 | 1222.4 | 52 | 28.6 | 11 | 185.45 |
| 46 | 1340 | 60.4 | 143 | 1205 | 1171.4 | 1235 | 1146 | 1248.3 | 40 | 31.8 | 11 | 217.52 |
| 48 | 1390 | 63.6 | 148 | 1257 | 1222.2 | 1289 | 1196.8 | 1335.1 | 44 | 31.8 | 11 | 235.84 |
| 50 | 1445 | 66.8 | 152 | 1308 | 1273 | 1340 | 1247.6 | 1385.9 | 4 | 31.8 | 11 | 277.6 |
| 52 | 1495 | 68.4 | 156 | 1360 | 1323.8 | 1391 | 1298.4 | 1436.7 | 52 | 31.8 | 11 | 274.8 |
| 54 | 1550 | 70 | 160 | 1413 | 1374.6 | 1441 | 1349.2 | 1492.2 | 56 | 31.8 | 11 | 298.15 |
| 56 | 1600 | 71.6 | 165 | 1465 | 1425.4 | 1492 | 1400 | 1543 | 60 | 31.8 | 14 | 315.74 |
| 58 | 1675 | 73.1 | 173 | 1516 | 1476.2 | 1543 | 1450.8 | 1611.3 | 48 | 34.9 | 14 | 375.36 |
| 60 | 1725 | 74.7 | 178 | 1570 | 1527 | 1600 | 1501.6 | 1662.1 | 52 | 34.9 | 14 | 397.93 |
API 605 Flange Pressure Classes
API 605 flanges are available in a range of pressure classes, which define the maximum pressure they can safely handle. These flanges are typically used in higher-pressure systems than many other flanges, ranging from 1,000 psi to 5,000 psi or more. The common pressure classes for API 605 flanges include:
- 1,000 psi
- 1,500 psi
- 2,500 psi
- 5,000 psi
High-Temperature Applications
API 605 flanges are suitable for high-temperature applications where piping systems are exposed to elevated temperatures. These flanges are designed to perform well in environments that reach temperatures up to 1,000°F (537°C). High-temperature applications include:
- Refinery Steam Lines: Steam systems in refineries and other industrial facilities use API 605 flanges.
- Power Plants: These flanges can handle the heat and pressure conditions found in power generation systems.
- Gas and Oil Processing: Used in gas and oil processing facilities, where temperatures and pressures are often elevated.
Manufacturing Process
Raw Material Selection – High-quality steel is chosen based on the required specifications.
Forging – The steel is heated and shaped into the desired flange form.
Machining – Precision machining is carried out to achieve the required dimensions and surface finish.
Drilling – Bolt holes are drilled according to the standard flange pattern.
Heat Treatment – The flange undergoes heat treatment processes like normalizing or quenching to enhance mechanical properties.
Inspection & Testing – Flanges are tested for dimensional accuracy, pressure resistance, and material integrity.
Surface Treatment – Anti-corrosion coatings, such as galvanization or epoxy coating, may be applied.
Low-Temperature Applications
API 605 flanges are also designed for low-temperature environments, where the materials are selected for their ability to perform under freezing or sub-zero temperatures. These flanges can be used in applications where temperatures drop to as low as -50°F (-46°C). Typical low-temperature applications include:
- Arctic Operations: For pipeline systems or processing plants in cold climates, including offshore Arctic drilling.
- Subsea Pipelines: These flanges are used in subsea systems where low temperatures and high pressure are common.
- Cryogenic Systems: Used in cryogenic applications where liquefied gases need to be transported or processed.
Materials
API 605 flanges are constructed from materials that provide the strength, durability, and resistance to corrosion necessary for their demanding applications. Common materials include:
- Carbon Steel: Often used for general-purpose applications, carbon steel provides strength and moderate corrosion resistance at a cost-effective price.
- Alloy Steel: Alloy steels, such as 5% chromium, offer increased strength and resistance to high-temperature environments.
- Stainless Steel: Stainless steel provides superior resistance to corrosion, making it ideal for harsher environments, including marine and subsea applications.
- Nickel Alloys: Used for extreme conditions, including environments with high corrosion and high temperatures.
- Inconel: The most demanding high-temperature, high-pressure applications use this high-performance alloy.
Manufacturing Process
Raw Material Selection – High-quality steel is chosen based on the required specifications.
Forging – The steel is heated and shaped into the desired flange form.
Machining – Precision machining is carried out to achieve the required dimensions and surface finish.
Drilling – Bolt holes are drilled according to the standard flange pattern.
Heat Treatment – The flange undergoes heat treatment processes like normalizing or quenching to enhance mechanical properties.
Inspection & Testing – Flanges are tested for dimensional accuracy, pressure resistance, and material integrity.
Surface Treatment – Anti-corrosion coatings, such as galvanization or epoxy coating, may be applied.
Flange Face Types
API 605 flanges are available in a variety of flange face types to accommodate different sealing needs:
- Flat Face (FF): A flat surface around the bolt holes for a simple gasket seal, used in lower-pressure applications.
- Raised Face (RF): This type features a raised area around the bolt holes to enhance the sealing pressure, improving leak resistance.
- Ring-Type Joint (RTJ): A metal ring gasket can be inserted into a groove on the flange face to create a tight seal in high-pressure and high-temperature applications.
- Male and Female (M/F): This face type features a male and female connection to ensure a secure, leak-proof seal under high pressure.
Application
- Oil & Gas Industry – Used in pipelines, refineries, and offshore platforms.
- Petrochemical Industry – Essential for chemical processing and storage facilities.
- Power Plants – Used in steam, water, and gas pipelines in thermal and nuclear plants.
- Marine & Shipbuilding – Suitable for marine applications due to their corrosion resistance.
- Water Treatment Plants – Used in large-diameter pipelines for water distribution.
