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What are threaded pipe fittings?

What are threaded pipe fittings?


What is the threaded pipe fitting ?

Threaded joints probably represent the oldest method of joining piping systems. Like socket weld pipe fittings, threaded pipe fittings are mainly used for small pipe sizes,commonly for piping whose nominal diameter is NPS 2 or smaller.Threaded pipe fittings are one of the most common in industry and life fittings,it easier to connect and remove,also saves the cost of the pipe connection.

The threaded pipe fitting is usually metal manufacturing in industry, which can resist high pressure,such as carbon steel, stainless steel, alloy steel, brass etc; the material is generally have a PC, PVC, PE, PPR etc in left.

The dimensional standards for taper pipe threads are as per ASME B1.20.1. That standard gives all required dimensions including number of threads per inch, pitch diameter, and normal engagement lengths for all pipe diameters.

  • Threaded piping is commonly used in low-cost, noncritical applications such as domestic water, fire protection, and industrial cooling water systems.
  • Threaded fittings are normally made of cast gray or malleable iron, cast brass or bronze, or forged alloy and carbon steel.
  • They are available in three pressure ratings: Class 2000, 3000 and 6000.

Fittings for threaded pipe systems:

Threaded 90 degree elbow Threaded 45 degree elbow Threaded tee Threaded cross
This elbows make 90° changes of direction in the run of pipe. This elbows make 45° changes of direction in the run of pipe. This Tee makes 90° branch from the main run of pipe. Crosses makes 90° branch from the main run of pipe.
Threaded full coupling Threaded half coupling Threaded end cap Threaded square head plug
A Full Coupling, joins pipe two pipe or to a nipple etc. The Half Coupling can be directly welded to the run pipe, to make a branch connection. Seals the threaded end of pipe. Seals the threaded end of fitting.
Threaded hex head plug Threaded round head plug Threaded hex head bushing Threaded union
Threaded hex head plug Seals the threaded end of pipe Seals the threaded end of fitting. Unions are primarily used for maintenance and installation purposes.

The advantages of threaded pipe fittings:

1.Installation productivity is moderately high, and specialized installation skill requirements are not extensive.

2.Leakage integrity is good for low-pressure, low-temperature installations where vibration is not encountered.


The disadvantages of threaded pipe fittings:

1.Rapid temperature changes may lead to leaks due to differential thermal expansion between the pipe and fittings.

2. Vibration can result in fatigue failures of screwed pipe joints due to the high stress intensification effects caused by the sharp notches at the base of the threads.

3.In piping systems threaded connections should be avoided, if possible. Their vulnerability to fatigue damage is significant, especially where exposed threads are subject to corrosion.

Haihao group have a nearly 30 years socket weld pipe fittings manufacture experience. we can supply suitable products as per your request. Besides these standard products, we also can supply customized butt welding pipe fittings accordingly.

We sincerely welcome customers domestic and abroad to visit us for cooperation and development.