ASTM A182 Stainless steel coupling are a type of fitting used to connect stainless steel pipes, usually made of stainless steel. They are widely used in high pressure piping systems up to 4 inches. They have the advantages of easy installation, safety and stability, good sealing, corrosion resistance and high temperature resistance, etc. They are tightened to keep the connection of the pipeline firm by being set on the pipeline. Stainless steel coupling has excellent corrosion resistance and durability. It is widely used in automotive, machinery, water supply and drainage systems, chemical equipment, food processing and marine industries to ensure that pipe connections are sealed firmly to prevent leakage.
ASTM A182 Stainless Steel Coupling Chemical Composition
| CHEMICAL | LIMITS | C | Mn | P | S | Si | Ni | Cr | Mo | N | Cu |
| ASTM A182 F304 | MIN | 8 | 18 | ||||||||
| MAX | 0.08 | 2 | 0.045 | 0.03 | 1 | 11 | 20 | 0.1 | |||
| ASTM A182 F316 | MIN | 10 | 16 | 2 | |||||||
| MAX | 0.08 | 2 | 0.045 | 0.03 | 1 | 14 | 18 | 3 | 0.01 | ||
| ASTM A182 F44 | MIN | 17.5 | 19.5 | 6 | 0.5 | ||||||
| MAX | 0.02 | 1 | 0.03 | 0.01 | 0.8 | 18.5 | 20.5 | 6.5 | 1 | ||
| ASTM A182 F51 | MIN | 4.5 | 21 | 2.5 | 0.08 | ||||||
| MAX | 0.03 | 2 | 0.03 | 0.02 | 1 | 6.5 | 23 | 3.5 | 0.2 | ||
| ASTM A182 F53 | MIN | 6 | 24 | 3 | 0.24 | ||||||
| MAX | 0.03 | 1.2 | 0.035 | 0.02 | 0.8 | 8 | 26 | 5 | 0.32 | 0.5 |
ASTM A182 Stainless Steel Coupling Mechanical Property
| MATERIAL | ASTM A182 F304 | ASTM A182 F316 | ASTM A182 F44 | ASTM A182 F51 | ASTM A182 F53 |
| T.S (MPA) | 515 min | 515 min | 650 min | 620 min | 800 min |
| Y.S (MPA) | 205 min | 205 min | 300 min | 450 min | 550 min |
| EL % | 30 min | 30 min | 35 min | 35 min | 25 min |
| R/A % | 50 min | 50 min | 50 min | 45 min | 15 min |
Classification of Stainless Steel Coupling
Socket Weld Coupling
The coupling that connect pipes in the form of socket welding are called socket weld coupling. Its connection form is to insert the steel pipe into the socket hole for welding. There are two types of socket weld coupling : full socket weld coupling and half socket welding coupling. Due to the adoption of the socket structure, the cost of the pipe joint is reduced, and the installation, use and maintenance are extremely convenient.
The stainless steel socket weld coupling is a pipe connector that is machined after round steel or steel ingot die forging. It adopts the socket welding connection method, that is, the steel pipe is inserted into the socket hole for welding.
Features and advantages:
Easy installation: Socket-type connections are usually easy to operate and do not require complex thread processing.
Good sealing: The use of sockets and spigots provides excellent leakage resistance.
Compact structure: Due to the compact design of the connection part, the socket-type pipe fittings are suitable for installation environments with limited space.
Low fluid resistance: The interior is smooth to reduce fluid resistance.
Threaded Coupling
Stainless steel threaded coupling are an important pipeline connection accessory. It is widely used in industries such as oil, natural gas, chemicals, and water treatment. It fixes and connects stainless steel pipes through threaded connections to achieve a tight connection between pipes and ensure the sealing and stability of the pipeline system. Stainless steel threaded coupling can withstand certain pressures and temperatures to meet the use requirements of various pipeline systems.
Features and advantages:
Firm connection: Threaded connections have strong pull-off resistance and can withstand high working pressures.
Disassembly: This is a major advantage of threaded coupling, which facilitates maintenance, overhaul, replacement of parts or future transformation of pipeline systems.
Wide range of applications: Suitable for piping systems of various pressure levels and multiple media.
Stainless Steel Socket Weld Coupling Specification
| Type | Coupling |
| Shape | Full Coupling & Half Coupling |
| Size Range | 1/8″ – 4″ / DN6 – DN100 |
| Pressure Rating | Class 3000lbs, 6000lbs, 9000lbs |
| Stainless Steel | ASTM A182 F304/304L/304H, F316/316L, F321, F310S, F317, F347, F904L |
| Duplex Stainless Steel | ASTM A182 F51, F53, F44 |
ASME B16.11 Socket Weld Coupling Dimensions
| DN | NPS | B | D | C | |||||||
| 3000 | 6000 | 9000 | 3000 | 6000 | 9000 | ||||||
| 6 | 1/8 | 10.9 | 6.1 | 3.2 | – | 3.18 | 3.18 | 3.96 | 3.43 | – | – |
| 8 | 1/4 | 14.3 | 8.5 | 5.6 | – | 3.78 | 3.30 | 4.60 | 4.01 | – | – |
| 10 | 3/8 | 17.7 | 11.8 | 8.4 | – | 4.01 | 3.50 | 5.03 | 4.37 | – | – |
| 15 | 1/2 | 21.9 | 15.0 | 11.0 | 5.6 | 4.67 | 4.09 | 5.97 | 5.18 | 9.53 | 8.18 |
| 20 | 3/4 | 27.3 | 20.2 | 14.8 | 10.3 | 4.90 | 4.27 | 6.96 | 6.04 | 9.78 | 8.56 |
| 25 | 1 | 34.0 | 25.9 | 19.9 | 14.4 | 5.69 | 4.98 | 7.92 | 6.93 | 11.38 | 9.96 |
| 32 | 11/4 | 42.8 | 34.3 | 28.7 | 22.0 | 6.07 | 5.28 | 7.92 | 6.93 | 12.14 | 10.62 |
| 40 | 11/2 | 48.9 | 40.1 | 33.2 | 27.2 | 6.35 | 5.54 | 8.92 | 7.80 | 12.7 | 11.12 |
| 50 | 2 | 61.2 | 51.7 | 42.1 | 37.4 | 6.93 | 6.04 | 10.92 | 9.50 | 13.84 | 12.12 |
| 65 | 21/2 | 73.9 | 61.2 | – | – | 8.76 | 7.62 | – | – | – | – |
| 80 | 3 | 89.9 | 76.4 | – | – | 9.52 | 8.30 | – | – | – | – |
| 100 | 4 | 115.5 | 100.7 | – | – | 10.69 | 9.35 | – | – | – | – |
Threaded Coupling Specification
| Type | Coupling |
| Shape | Coupling & Half Coupling |
| Size Range | 1/8″ – 4″ / DN6 – DN100 |
| Pressure Rating | Class 3000lbs, 6000lbs |
| Stainless Steel | ASTM A182 F304/304L/304H, F316/316L, F321, F310S, F317, F347, F904L |
| Duplex Stainless Steel | ASTM A182 F51, F53, F44 |
ASME B16.11 Threaded Coupling Dimension
| Nominal Size | End-to-End | Outside Diameter | Length of Thread | |||
| DN | NPS | W | D | L 5 min | L 2 min | |
| 3000 & 6000 | 3000 | 6000 | ||||
| 6 | 1/8 | 32 | 16 | 22 | 6.4 | 6.7 |
| 8 | 1/4 | 35 | 19 | 25 | 8.1 | 10.2 |
| 10 | 3/8 | 38 | 22 | 32 | 9.1 | 10.4 |
| 15 | 1/2 | 48 | 28 | 38 | 10.9 | 13.6 |
| 20 | 3/4 | 51 | 35 | 44 | 12.7 | 13.9 |
| 25 | 1 | 60 | 44 | 57 | 14.7 | 17.3 |
| 32 | 11/4 | 67 | 57 | 64 | 17.0 | 18.0 |
| 40 | 11/2 | 79 | 64 | 76 | 17.8 | 18.4 |
| 50 | 2 | 86 | 76 | 92 | 19.0 | 19.2 |
| 65 | 21/2 | 92 | 92 | 108 | 23.6 | 28.9 |
| 80 | 3 | 108 | 108 | 127 | 25.9 | 30.5 |
| 100 | 4 | 121 | 140 | 159 | 27.7 | 33.0 |
Difference between Socket Weld Coupling and Threaded Coupling
Socket weld coupling
Characteristics: Pipes or pipe fittings are connected by socket and welding, which has high connection strength and sealing performance. It is characterized by a socket with a socket slot, the socket and socket are located at the two ends of the curved part, which is reasonable in design, simple in operation and practical.
Connection method:The connection is realized by inserting the pipe end into the socket weld coupling, and then by welding, bonding or mechanical compression.
Threaded coupling
Characteristics: Connecting pipes or pipe fittings through threads without welding, easy to install and dismantle, but the connection strength and sealing performance are relatively low.
Connection method: rely on the internal threads of the coupling to screw with the external threads of the pipe, usually used with a sealant.
Application of Stainless Steel Coupling
Water treatment and water supply and drainage systems
Food and beverage production equipment
Automobile and engine exhaust systems
Petrochemical and chemical pipeline connections
Medicine, clean room equipment pipeline sealing
How to choose the right stainless steel coupling?
Medium type and temperature : different media and temperature will affect the choice of stainless steel material grade and connection.
Working pressure : Working pressure is an important basis for selecting the pressure bearing capacity of the clamp.
Installation environment and space: Socket connection may be more advantageous in a small space.
Frequent disassembly : The pipeline system needs regular maintenance, inspection or modification, and the disassembly of the threaded clamp will be an important consideration.
Cost Estimates : Consider the cost of purchasing the hoop, the cost of installation, and the cost of maintenance over time.