Threaded Flanges-Forged Flanges-Forgings Company in China-Kingrail Parts

Threaded Flanges

Description

Threaded flanges, sometimes called companion flanges/screw flanges/NPT flanges, contain an NPT internal thread in the center for connection to NPT external threaded pipe.

It is worth noting that threaded flanges are common when creating reducing connections. In addition to the standard NPT threads specified by the ASME B16.5 specification, there are other thread types that can be processed.

The most commonly used threaded flanges are available in nominal pipe sizes ranging from ½ inch to 6 inches, but if necessary, we can provide NPT threaded flanges up to 24 inches.

The production of larger diameter threaded connections requires a lot of processing and labor, which makes them less popular than slip-on or weld neck constructions.

It can be very useful for applications that need to be connected and disconnected from time to time. The external threaded pipe end can be connected to the flange without welding, but it can be sealed by welding when necessary, especially for pipe fitting safety.

This weld seal defeats the purpose of the threaded flange as a structural choice, because its main advantage is to assemble and disassemble the connection.

For pressure vessel equipment, if the user is sure that the pipe and flange assembly must be kept permanently sealed, a weld seal can be adopted.

When using male NPT pipe connections and the media involved is highly reactive or explosive, a threaded flange connection is often required, which is why NPT/threaded companion flanges are commonly used in API oilfield services.

API 6A specifications also allow for male threaded flange connections, but these are less common than the female NPT in the center.

Specification

Nominal pipe size	Thread density	Thread Pitch		Hand-Tight Engagement			Effective Thread			Overall Length	Actual Outside Diameter OD		Tap drill
Nominal pipe size	Thread density	inch	mm	Length	Turns	Diameter	Length	Turns	Diameter	Overall Length	inch	mm	inch	mm
inch	inch⁻¹	inch	mm	inch	-	inch	inch	-	inch	inch	inch	mm	inch	mm
1/16	27	0.03703704	0.9407	0.1600	4.32	0.28118	0.2611	7.05	0.2875	0.3896	0.313	7.95	-	-
1/8	27	0.03703704	0.9407	0.1615	4.36	0.37360	0.2639	7.13	0.38000	0.3924	0.405	10.287	0.339	8.6106
1/4	18	0.05555555	1.41111	0.2278	4.10	0.49163	0.4018	7.23	0.50250	0.5946	0.540	13.716	7/16	11.113
3/8	18	0.05555555	1.41111	0.2400	4.32	0.62701	0.4078	7.34	0.63750	0.6006	0.675	17.145	37/64	14.684
1/2	14	0.07142857	1.8143	0.3200	4.48	0.77843	0.5337	7.47	0.79178	0.7815	0.840	21.3360	23/32	18.2563
3/4	14	0.07142857	1.8143	0.3390	4.75	0.98887	0.5457	7.64	1.00178	0.7935	1.050	26.6700	59/64	23.4156
3/4	11 1/2	0.08695652	2.2087	0.4000	4.60	1.23863	0.6828	7.85	1.25631	0.9845	1.315	33.4010	1 5/32	29.3688
1 1/4	11 1/2	0.08695652	2.2087	0.4200	4.83	1.58338	0.7068	8.13	1.60131	1.0085	1.660	42.1640	1 1/2	38.1000
1 1/2	11 1/2	0.08695652	2.2087	0.4200	4.83	1.82234	0.7235	8.32	1.84131	1.0252	1.900	48.2600	1 47/64	44.0531
2	11 1/2	0.08695652	2.2087	0.4360	5.01	2.29627	0.7565	8.70	2.31630	1.0582	2.375	60.3250	2 7/32	56.3563
2 1/2	8	0.12500000	3.1750	0.6820	5.46	2.76216	1.1375	9.10	2.79063	1.5712	2.875	73.0250	2 5/8	66.6750
3	8	0.12500000	3.1750	0.7660	6.13	3.38850	1.2000	9.60	3.41563	1.6337	3.500	89.9000	3 1/4	82.5500
3 1/2	8	0.12500000	3.1750	0.8210	6.57	3.88881	1.2500	10.00	3.91563	1.6837	4.000	101.6000	3 3/4	95.2500
4	8	0.12500000	3.1750	0.8440	6.75	4.38713	1.3000	10.40	4.41563	1.7337	4.500	114.3000	4 1/4	107.9500
5	8	0.12500000	3.1750	0.9370	7.50	5.44929	1.4063	11.25	5.47863	1.8400	5.563	141.3002	5 9/32	134.1438
6	8	0.12500000	3.1750	0.9580	7.66	6.50597	1.5125	12.10	6.54063	1.9462	6.625	168.2750	6 11/32	161.1313
6	8	0.12500000	3.1750	0.9580	7.66	6.50597	1.5125	12.10	6.54063	1.9462	6.625	168.2750	6 11/32	161.1313
8	8	0.12500000	3.1750	1.0630	8.50	8.50003	1.7125	13.70	8.54063	2.1462	8.625	219.0750	-	-
10	8	0.12500000	3.1750	1.2100	9.68	10.62094	1.9250	15.40	10.66563	2.3587	10.750	273.0500	-	-
12	8	0.12500000	3.1750	1.3600	10.88	12.61781	2.1250	17.00	12.66563	2.5587	12.750	323.8500	-	-
14	8	0.12500000	3.1750	1.5620	12.50	13.87263	2.2500	18.00	13.91563	2.6837	14.000	355.6000	-	-
16	8	0.12500000	3.1750	1.8120	14.50	15.87575	2.4500	19.60	15.91563	2.8837	16.000	406.4000	-	-
18	8	0.12500000	3.1750	2.0000	16.00	17.87500	2.6500	21.20	17.91563	3.0837	18.000	457.2000	-	-
20	8	0.12500000	3.1750	2.1250	17.00	19.87031	2.8500	22.80	19.91563	3.2837	20.000	508.0000	-	-
24	8	0.12500000	3.1750	2.3750	19.00	23.86094	3.2500	26.00	23.91563	3.6837	24.000	609.6000	-	-

Kingrail Parts stocks flanges in a variety of sizes and specifications.

Frequently Asked Questions (FAQ)

1. What is a threaded flange?

A threaded flange is a pipe flange that has internal threads on the hole that screw directly onto the external threads of the pipe.

This design eliminates the need for welding, making it a convenient option for pipes that cannot be welded or where welding is not appropriate.

2. What are the advantages of a threaded flange?

A threaded flange can be easily screwed onto a pipe without the need for welding or additional sealing methods, making it faster and more straightforward to install or remove.

Threaded flanges are generally less expensive than welded or slip-on flanges because they do not require welding labor or specialized equipment.

3. When should a threaded flange be used?

Threaded flanges are best used in applications where pressure is not very high, as they are not designed to withstand the pressures associated with high-pressure systems.

4. For systems that require regular maintenance or replacement of parts, such as temporary pipe installations or test fixtures, threaded flanges can be easily assembled and disassembled.

5. When should threaded flanges not be used?

Threaded flanges are not suitable for systems involving high internal pressures, as the threads may fail or leak under such pressures.

In applications with high vibration, threaded flanges may not be held firmly for long, resulting in loosening and potential leaks.

5. How to install threaded flanges?

Clean the pipe threads and the inside of the flange to ensure a secure and leak-free connection. Align the threaded flange with the pipe and screw it onto the pipe threaded end by hand until it is tight.

Use a wrench to further tighten the flange onto the pipe. Be careful not to overtighten, as this may damage the threads or pipe. You can also use thread sealant or Teflon tape to prevent leaks in low-pressure systems to ensure a tight seal.

Get more help

Kingrail Parts offers a wide range of forged flanges. If you need a forged flange, please contact us. Our flange experts will give you the best advice and a free quote.