Socket Weld (SW) fittings are defined in the ASME B16.11. The fitting has a socket or recessed area where the pipe is inserted. The end of the pipe sits against the shoulder of the socket. After the pipe is inserted into the fitting, a fillet weld is applied around the circumference of the pipe at the fitting interface. Both the pipe and the fitting are square cut, with no need for beveled end or preparation other than cleaning the outside, which allows easy welding and installation.
The material of socket weld fittings from malleable iron fittings company, can be carbon steel or stainless steel. The standard of carbon steel is ASTM A105 and the standard of stainless steel is ASTM A182.
Butt weld (BW) fittings are defined in the ASME B16.9. They are welded at their ends to pipe end, with the same thickness as pipes. The end of butt weld fittings shall be beveled.
The material of socket weld fittings can be carbon steel or stainless steel. The standard of carbon steel is ASTM A234 (WPB) and the standard of stainless steel is ASTM A403
Draws
Application
Socket weld (SW) fittings as Forged Pipe Fitting commonly used in high-pressure systems, plumbing, gas lines, and industrial piping systems where a strong, leak-proof connection is essential. The working pressure can be class 3000 (3000 PSI), class 6000 (6000 PSI)
Butt weld (BW) fittings keep better strength, good for high pressure or high temperature pipelines. So it is used when a welded joint with strength not lower than that of the base metal itself is needed.Working pressure as below,
| Temperature (°F) | Schedule 40 (psi) | Schedule 80 (psi) |
| 100 | 285 | 400 |
| 200 | 260 | 375 |
| 300 | 230 | 350 |
| 400 | 200 | 325 |
Feature
Socket weld (SW) fittings
- Strength: Creates a strong, durable connection.
- Easy to install: Easier to align compared with butt weld fittings
- Leakage prevention: Reduced risk of leakage compared to threaded fittings
- High working pressure: Reach to 6000PSI
Butt weld (BW) fittings
Butt weld is the “best” in terms of strength, fatigue, and corrosion resistance, and temperatures compliance. However, it is more difficult to fit-up and weld properly, needing skilled welder and much time.
Price
Normally, the price of Socket weld fittings is higher than Butt weld fittings in similar size. But the extra cost of butt weld is higher for installation, considering labor cost and skilled welder.
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