CS Forged Fitting：
Connected Type: Socket-welded / Threaded
Products Range: Elbows, Tees, Full-Couplings, Half-Couplings,Reducing-Couplings, Unions, Caps,Outlets
Size Range: 1/4"(DN8)~4"(DN100)
Pressure: 2000LB, 3000LB,6000LB,9000LB
Material Grades: ASTM A105N
Threads: NPT.BSPT,BSPP,BSP
Standards: ASME B16.11, MSS-SP-79,MSS-SP-83,MSS-SP-97
Socket-Welded
A Socket Weld is a pipe attachment detail in which a pipe is inserted into a recessed area of a Valve, fitting or flange. In contrast to buttweld fittings, Socket Weld fittings are mainly used for small pipe diameters (Small Bore Piping); generally for piping whose nominal diameter is NPS 2 or smaller.
To join pipe to Valves and fittings or to other sections of pipe, fillet-type seal welds be used. Socket Welded Joints construction is a good choice wherever the benefits of high leakage integrity and great structural strength are important design considerations.
Fatigue resistance is lower than that in butt-welded construction due to the use of fillet welds and abrupt fitting geometry, but it is still better than that of most mechanical joining methods.
They are used for lines conveying flammable, toxic or expensive material where no leakage can be permitted, and for steam 300 to 600 PSI.
They are used only in conjunction with ASME Pipe and are available in the same size range.
They are used in areas where pipe-work is permanent and are designed to provide good flow characteristics
Advantages
1.The pipe need not be beveled for weld preparation.
2.Temporary tack welding is no needed for alignment, because in principle the fitting ensures proper alignment.
3.The weld metal cannot penetrate into the bore of the pipe.
4.They can be used in place of threaded fittings, so the risk of leakage is much smaller.
5.Radiography is not practical on the fillet weld; therefore correct fitting and welding is crucial. The fillet weld may be inspected by surface examination, magnetic particle (MP), or liquid penetrant (PT) examination methods.
6.Construction costs are lower than with butt-welded joints due to the lack of exacting fit-up requirements and elimination of special machining for butt weld end preparation.
Disadvantages
1.The welder should ensure for a expansion gap of 1/16 inch (1.6 mm) between de pipe and the shoulder of the socket.
ASME B31.1 para. 127.3 Preparation for Welding (E) Socket Weld Assembly says:
In assembly of the joint before welding, the pipe or tube shall be inserted into the socket to the maximum depth and then withdrawn approximately 1/16" (1.6 mm) away from contact between the end of the pipe and the shoulder of the socket.
2.The expansion gap and internal crevices left in socket welded systems promotes corrosion and make them less suitable for corrosive or radioactive applications where solids buildup at the joints may cause operating or maintenance problems. Generally require butt welds in all pipe sizes with complete weld penetration to the inside of the piping.
3.Socket welding are unacceptable for Ultra High Hydrostatic Pressure (UHP) in Food Industry application since they do not permit full penetration and leave overlaps and crevices that are very difficult to clean, creating virtual leaks.
Types of socket weld fittings by class, size and wall thickness
Threaded
Threaded joints probably represent the oldest method of joining piping systems. Like Socket Weld fittings, threaded fittings are mainly used for small pipe diameters (Small Bore Piping); generally for piping whose nominal diameter is NPS 2 or smaller.
The dimensional standards for taper pipe threads are given in ASME B1.20.1. That document 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.
Advantages
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.
Disadvantages
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 hazardous piping systems threaded connections should be avoided, if possible. Their vulnerability to fatigue damage is significant, especially where exposed threads are subject to corrosion
Types of Threaded Fittings by Class and Size
