Socket Weld Fitting
Socket welding pipe fittings are connectors designed specifically for high pressure and small diameter pipe systems ≤NPS 2. This type of pipe fittings will reserve a socket in advance, and the pipe will be inserted into this socket when in use. The socket is firmly connected through the welding process, which can ensure leak-proof performance in key industries such as oil and gas, pharmaceuticals, and power plants. These pipe fittings comply with ASME B16.11 standards, have compact installation, reduce stress concentration, and provide long-term durability for fluid systems.
Socket Weld Fitting Specifications
Socket depth: ≥1.25 times the wall thickness of the pipe
Bevel angle: 45°~60
Tolerance of inner diameter: ±0.1mm
Standard: ASME B16.11, EN 10253
Material: carbon steel, stainless steel, duplex steel
Temperature range: -29°C~425°C (carbon steel)
Socket welding pipe fittings should strictly follow international standards during design and manufacturing. To ensure the strength of the weld, the socket depth must be ≥1.25 times the wall thickness. To ensure the fusion depth of the weld, the groove angle should be controlled at 45°~60°. To reduce fluid turbulence, the inner diameter tolerance is kept within ±0.1mm. The American standard (ASME) and the European standard (EN 10253) are slightly different in pressure levels and test requirements. When selecting, you need to match them according to the standards of the project.
Socket Weld Fitting Process
The manufacturing process is divided into four steps: precision forging, CNC machining, welding and post-processing.
During the forging stage, the material is heat treated, carbon steel is heated to 1200°C, and stainless steel is heated to 950°C to facilitate molding in the mold. The grain structure will be rearranged during forging, and the grain size will eventually reach ASTM E112 Grade 5 or higher.
CNC machining is performed with carbide tools to ensure that the inner wall roughness of the socket is ≤0.8μm.
Welding should use a low welding process with a current of 80~150ATIG, argon protection, and annealing or solution treatment is required after welding to eliminate residual stress.
Finally, the weld is annealed or solution treated to eliminate residual stress. Liquid penetrant (PT) and radiographic testing (RT) are used to ensure that the weld is defect-free.
Socket Weld Pipe Fitting Advantages
1. Installation Efficiency
During the installation process, the flange is directly inserted into the socket groove and circumferentially welded. Compared with traditional flanges, this method simplifies the installation process and reduces working time.
2. Compact Design
Space-saving structure: Socket weld fittings are 15–20% shorter than butt weld fittings of the same specification (e.g., NPS 1 elbow), making them ideal for instrument lines and confined spaces.
3. High Sealing Performance
Full perimeter welding integrity: The biggest advantage is that it can effectively eliminate leakage points. It is suitable for non-corrosive gases (instrument air, nitrogen) and low-viscosity liquids under medium and low pressures (≤10 MPa, in accordance with ASME B16.11).
4. Vibration Resistance
Vibration energy absorption: The socket structure can absorb vibration to a certain extent, attenuating the damage caused by vibration, and performs better than threaded connections in dynamic environments.
Selection and Application Scenarios
Small-diameter pipelines: To ensure safety, pipeline systems below NPS 2 (DN50) should be preferred and must comply with ASME B16.11 standards.
Medium and low pressure conditions: Mainly suitable for medium and low pressure conditions, so the maximum working pressure cannot exceed 10 MPa, and the temperature should be between -20°C and 350°C.
Medium characteristics considerations: Mainly non-corrosive gases and low-viscosity liquids, so when using it, it is necessary to avoid conveying fluids containing granular media and high flow rates (over 3 m/s).
Material selection: Carbon steel (such as A105/A106), stainless steel (such as 304 and 316L) and copper-nickel alloys (such as C70600) are all good material choices, but it is important to keep the selected material consistent with the pipe material.
Standard reference: Refer to ASME B16.11, CJ/T 321-2010 (or MSS SP-83).