Contact us

What are NPT Threaded Fittings?

NPT Threaded Fittings are pipe fittings manufactured in accordance with the NPT tapered pipe thread standard established by the American National Standards Institute (ANSI). The NPT thread is a U.S. standard tapered thread, distinguished by its taper angle, typically 3/4 inch per foot. It is this taper that allows male and female threads to fit tightly together when screwed together, forming a mechanical seal. Threaded fittings include various types such as elbows, tees, pipe clamps, pipe caps, and plugs, used for connecting, redirecting, branching, or sealing off pipeline systems.

Threaded Fittings are commonly used in water gas pipes, small-diameter water pipes, compressed air pipes, and low-pressure steam pipes. They are connected to threaded pipe ends to form a pipeline. A suitable adhesive can be applied to the threads to ensure sealing. This design not only provides excellent connection strength but also reduces the risk of fluid leakage, making it an ideal choice for low- to medium-pressure pipeline systems.

Material & Grades of Forged Threaded Fittings 

Carbon Steel :
ASTM A105 / A105N,ASTM A350 LF2 / LF3, A694 F42 / 46 / 52 / 56 / 65 / 70

Alloy Steel :
ASTM / ASME A/SA 182 & A 387 F1, F5, F9, F11, F12, F22, F91

Stainless Steel :
ASTM A 182, A 240 F 304, 304L, 304H, 316, 316L, 316Ti, 310, 310S, 321, 321H, 317, 347, 347H, 904L

Duplex & Super Duplex Steel :
ASTM / ASME A/SA 182 F 44, F 45, F51, F 53, F 55, F 60, F 61

Copper Alloy Steel :

 ASTM SB 61 , SB62 , SB151 , SB152 UNS No. C 70600 (Cu-Ni 90/10), C 71500 (Cu-Ni 70/30), UNS No. C 10100, 10200, 10300, 10800, 12000, 12200

Nickel Alloy :
ASTM SB564, SB160, SB472, SB162 Nickel 200 (UNS No. N02200), Nickel 201 (UNS No. N02201), Monel 400 (UNS No. N04400), Monel 500 (UNS No. N05500), Inconel 800 (UNS No. N08800), Inconel 825 (UNS No. N08825), Inconel 600 (UNS No. N06600), Inconel 625 (UNS No. N06625), Inconel 601 (UNS No. N06601), Hastelloy C 276 (UNS No.N10276), Alloy 20 (UNS No. N08020)

ASME B16.11 Threaded Fittings Types

Threaded fittings include elbows, tees, crosses, couplings, caps, unions, plugs, bushings, hexagonal nipples, etc.

	Threaded Elbow A threaded elbow is a pipe fitting used to change the direction of a pipe, with threads on one or both ends. It usually consists of an elbow body and a threaded part. The bending part of the elbow body is generally 90° or 45°.
	Threaded Tee Threaded Tee is usually used in some low-pressure small-diameter pipeline systems. It can divide the pipeline into three branches and form a 90-degree angle between the three branches.
	Threaded Cross Threaded Cross is a pipe connector with four openings, usually used to divide the pipe system into four different directions to achieve the diversion of the medium.
	Threaded Coupling The threaded coupling is a simple but important pipe connection fitting. Its main structure is a hollow cylinder with threads inside. The threads at both ends of the couplings are usually of the same specification so that it can be connected to threaded pipes of the same diameter.
	Threaded Cap A threaded cap is a pipe fitting used to close the end of a pipe. It is mainly composed of a cap body and a threaded part. The cap body is a hemispherical or flat-top structure with a hollow interior to fit the outer diameter of the pipe.
	Threaded Bushing Thread bushing is a technique used to repair damaged or worn threads by installing thread inserts made of special metals or alloys into the original thread holes to restore the dimensions and load-bearing capacity of the threads. This method not only extends the service life of parts, but also improves the strength and wear resistance of connections.
	Threaded Nipple A threaded nipple is a short pipe fitting with internal and external threads at both ends, used to connect two sections of threaded pipes to extend or transition the pipeline. It enables quick and reliable pipeline connections while facilitating maintenance and replacement.

Advantages of NPT Threaded Fittings

1. The primary reasons for choosing NPT threaded fittings over other connection methods are their significant advantages:
2. Easy Installation: No specialized welding equipment or technical expertise is required; installation and removal can be easily accomplished using a wrench. This significantly reduces construction costs and time.
3. Reusability: As a mechanical connection, NPT threaded fittings can be repeatedly disassembled and reassembled without damage, facilitating maintenance and adjustments to the piping system.
4. Excellent Sealing Performance: The tapered thread design creates compression when tightened, forming a reliable leak-proof seal. When installed with PTFE tape or thread sealant, the sealing effect can be further enhanced.
5. Cost-Effective: Compared to welded fittings, NPT threaded fittings typically have lower installation costs, especially for small-scale pipeline systems that require frequent adjustments or maintenance.

Advantages of NPT Thread

The tapered design provides strong sealing performance, making it suitable for high-pressure applications.

The NPT thread design is specifically engineered to achieve sealing through thread contact, eliminating the need for additional O-rings or gaskets.

It prevents sealant contamination of the medium, making it suitable for sensitive applications such as fuel and lubricants.

Strict dimensional parameters ensure good interchangeability between products from different manufacturers, making them widely compatible in North America and regions adhering to related standards.

Threaded Sealing Method

Teflon tape

A thin, white tape that fills the microscopic gaps between threads when tightened, preventing leaks. When using, it should be wound clockwise around the male thread, ensuring the winding direction aligns with the insertion direction.

– First, wrap the Teflon tape around the external threads in a clockwise motion.

– Overlap the tape halfway between each wrap to ensure a tight seal and complete coverage of the thread surface.

– Apply enough layers of Teflon tape to ensure a good seal on the threads without excessive residue that could prevent proper tightening.

Thread sealant

A liquid or paste-like sealant that cures after application to the threads, forming a stronger, more pressure-resistant seal. Suitable for high-pressure applications.

– Use a brush or applicator to evenly apply a thin layer of pipe sealant to the external threads.

– Ensure that the sealant is evenly applied to the entire thread surface, without clumps or excess residue.

– Use a pipe sealant that is suitable for the application and the type of fluid being conveyed through the fitting.

Difference Between BSP & NPT Threads

BSP and NPT are two different thread standards, with their primary differences lying in geographical region, thread angle, and sealing method. NPT (American Standard Tapered Pipe Thread) is primarily used in the United States and Canada, featuring a thread angle of 60 degrees. Sealing is achieved through the compression created by tightening the tapered thread, typically requiring the use of PTFE tape or sealant. BSP (British Standard Pipe Thread) is primarily used in Europe, Asia, and Commonwealth countries. It has a thread angle of 55 degrees and is divided into two types: tapered (BSPT) and parallel (BSPP). BSPT achieves sealing through the thread itself, while BSPP requires gaskets or O-rings for sealing at the end face. Due to differences in design and dimensions, these two thread types are incompatible.

How to Choose the Right NPT Threaded Fittings?

Material: Select the appropriate material based on the nature of the fluid, temperature, and pressure. For example, stainless steel (304/316) is suitable for corrosive media, while carbon steel or copper is suitable for general fluids.

Size: Ensure that the size of the fittings (e.g., 1/2 inch, 3/4 inch) matches your piping system perfectly.

Pressure Rating: Select the appropriate pressure rating (e.g. Class 3000) based on the system’s operating pressure to ensure the threaded fittings can withstand the pipeline’s working pressure and prevent leaks or damage.

Pipeline Layout: Use couplings for straight connections, elbows for direction changes, and tees for branching or merging.

Application of NPT Threaded Fittings

Oil and gas pipelines

Chemical equipment pipelines

Water treatment systems

Firefighting pipelines

Pharmaceutical industry

Food processing equipment

Air conditioning and refrigeration systems

Shipbuilding and marine engineering

Hydraulic and pneumatic systems

Building pipeline installation

The post NPT Threaded Fittings  appeared first on Supplier of Quality Forged Fittings-Flanges.

ZIZI is a company specializing in the production and processing of pipes and fittings. Our pipes and fittings are primarily used in the chemical, petroleum, natural gas, water conservancy, power generation, and marine engineering sectors. Our products include seamless pipes and welded pipes of various sizes, butt-weld fittings, high-pressure forged fittings, and flanges. Materials include carbon steel, stainless steel, alloy steel, cryogenic steel, duplex steel, and base alloys.

Inspection Photos

What is a 316 stainless steel threaded Nipple?

A threaded nipple is a short pipe fitting with threads on both ends, commonly used to connect two sections of pipe, valves, or equipment. It is easy to install and does not require welding. The 316 stainless steel short section is made of austenitic stainless steel containing molybdenum (Mo), which offers stronger corrosion resistance than 304 stainless steel. It is particularly suitable for working environments containing chloride ions or acidic/alkaline media.

ASTM A733 Threaded Nipple Specification

ASTM A182 F316 Threaded Fittings Chemical Composition

ASTM A182 F316 Threaded Fittings Mechanical Property

Classification of Threaded Nipple

One end threaded nipple

One end threaded nipple have threads machined on one end and a flat surface or socket on the other end, designed for connecting pipes that require threaded connections on one end. This structure makes them suitable for specific connection applications in piping systems. For example, when connecting equipment with an internal threaded joint to a pipe, the non-threaded end of the one end threaded nipple can be welded to the pipe or connected in another manner, while the threaded end is connected to the equipment’s internal threaded joint via the threaded connection.

Both end threaded nipple

Both end threaded nipple are threaded, making it suitable for connecting pipes or fittings that require threaded connections on both ends. This provides greater flexibility in pipe connections. Both end threaded nipple can be used to directly connect two pipes with external threads, or to connect a pipe with external threads to a device or fitting with internal threads.

ASTM A733 Threaded Nipple Dimensions

Why choose us?

We offer 316 stainless steel threaded nipple that comply with ASTM A312/A733 standards, supporting custom lengths, thread types, and special processing requirements. All products come with material test certificates (MTC 3.1) and third-party inspection services. With ample inventory, timely delivery, and reliable quality, we are your trusted stainless steel pipe fitting supplier.

For quotes, samples, or more information about 316 stainless steel threaded fittings, please feel free to contact us at any time!

Applicable Industries

Chemical Pipeline and Anti-corrosion System

Seawater Desalination Equipment

Food and Pharmaceutical Fluid Conveyance System

Oil and Gas Pipeline Connection

Water Treatment and Environmental Protection Equipment

The post 316 Stainless Steel Threaded Nipple Order appeared first on Supplier of Quality Forged Fittings-Flanges.

Most of forged threaded fittings are specified in ASME B16.11, including threaded elbow, threaded tee, half and full coupling, threaded cap, hex nipple, bushing and plug. ASME B16.11 is an American standard which popular internationally.

In addition to this, there are other common used standards and fittings such as BS 3799 threaded fittings, MSS-SP-97 threadolet, MSS-SP-83 union and ASME B36.19 nipple.

Threaded Pipe Fittings Catalogue

Threaded Elbow

It is shorten as THD elbow sometimes. Threaded elbow is used to connect pipe and change the directions of flow in 90 degree or 45 degree. The dimension of two end could be equal or reducing.

Threaded Tee

This threaded fittings has three outlets in same or different diameter. Like threaded elbows, branch in same diameter called equal / straight tee otherwise it is reducing tee.

Threaded Cap

The function of threaded caps is block off the flow at the end of pipes. It is also available in socket weld and buttweld end, pipe elbow and pipe tee as well.

Threaded Coupling

It is a short pipe with internal threaded at one end or both end. The former is half coupling and the latter is full coupling. The other end of half coupling will weld to pipes. This threaded pipe fitting also has reducing type.

Threaded Union

This threaded pipe fittings has the function to connect and adapt the diameter of pipes, but different with pipe coupling for allowing disconnection of the pipes for maintenance.

Threaded Nipple

Threaded nipple can be further divided into hex nipple, barrel nipple, close nipple and welding nipple, its function is similar as coupling and union.

Bushing

Bushing and plug are only available in threaded type. This threaded pipe fitting has male and female threads to connect pipes together.

Plug

Plug is a male threaded pipe fittings to stop pipe flow at the end. It has hex head, round head and square head three types.

Threadolet

Threadolet is a integrally reinforced branch outlet fittings which can offer branches from pipe header.

Thread Types of Forged Threaded Pipe Fittings

The threads are also available in different types, the most prevalent types are NPT, BSPP and BSPT.

NPT is the standard threads type for ASME B16.11 threaded pipe fittings, it is a tapered thread with 60°angles. Its connection requires the help of sealant.

BSPP is British standard parallel threads, its sealing requires a seal ring. BSPP threaded pipe fittings are popular in Asia, Europe, Australia and South Africa.

BSPT is also a British threads, but it is tapered with 55°angles. BSPT and BSPT belong to BSP threads, but they cannot use together.

Applications of ASME B16.11 Forged Fittings

Forged threaded pipe fittings can withstand high pressure up to class 6000, however, due to socket weld fittings have better leap-proof than threaded fittings, threaded fittings are more prevalent in lower pressure ratings. They are suitable for pipe system where welding is difficult to operate.

ASME B16.11 Threaded Pipe fittings are widely used in

• Oil and Gas
• Chemical
• Power station
• Shipbuilding
• Aerospace constructions

Advantages and Disadvantages of Threaded Fittings

Advantages

• Simple usage
• Easy installation
• Able to disconnection and convenient maintenance

Disadvantages

• Prone to leak due to rapid temperature changes
• Vibration and hazardous pipe system is not suit for threaded pipe fittings because they prone to be fatigue damaged.

Material Grades for Forged Steel Fittings

Stainless Steel Forged Threaded Fittings

ASTM A182 F304, F316, F310, F321, F309, F317

Carbon steel Forged Threaded Fittings

ASME A105, A350 LF/LF3, A106 A/B/C, API 5L, API 5L GR. B, API 5L X 42, X 46, X 52, X 60, X 65 & X 70.

Alloy Steel Forged Threaded Fittings

ASTM A182 F1, F5, F9, F11, F12, F22, F91

Duplex Stainless Steel Forged Threaded Fittings

ASTM A182 F51, F53, F55 / UNS S31803, S32205, S32550, S32750, S32950

Nickel Alloy Forged Threaded Fittings

UNS2200 (NICKEL 200) , UNS2201 (NICKEL 201 ) , UNS4400 (MONEL 400 ), UNS8825 (INCONEL 825) , UNS6600 (INCONEL 600 ) , UNS6601 (INCONEL 601) , UNS6625 (INCONEL 625) , UNS10276 (HASTELLOY C 276)

Copper Alloy Forged Threaded Fittings

UNS NO. C 70600 ( CU -NI- 45/10) , C 71500 ( CU -NI- 70/30), C 10100 , C 10200 , C 10300 , C 10800 , C 12000, C 12200

ASME B16.11 Threaded Fittings Weight Chart

The post What is Threaded Pipe Fittings? appeared first on Supplier of Quality Forged Fittings-Flanges.