Carbon Steel Threaded Fittings Manufacturer

Solitaire Overseas manufactures carbon steel threaded fittings in ASTM A105, machined to ASME B16.11 with NPT or BSPT threads for mechanically joined, small bore piping. A threaded joint seals through mechanical interference between matching male and female threads rather than by welding, making these fittings quick to install, dismantle and reuse during maintenance. Supplied in Class 2000, 3000 and 6000 across NPS 1/8 inch to 4 inch, our threaded range covers elbows, tees, couplings, unions, caps, plugs and bushings, each backed by full mill test certification.

Chemical Composition, Mechanical Properties and Thread Standard Reference

Chemical Composition Mechanical Properties Pressure Class NPT vs BSPT Specifications Dimensions Chart Pressure Rating Weight Chart

Chemical Composition (A105, %)

C max	Mn	P max	S max	Si
0.35	0.60 – 1.05	0.035	0.040	0.10 – 0.35

Mechanical Properties (A105)

Tensile Strength min	Yield Strength min	Elongation min	Hardness
485 MPa (70 ksi)	250 MPa (36 ksi)	22%	137 – 197 HB

Pressure Class Reference

Class	Approx. Working Pressure (non-shock, ambient)
2000	2000 psi
3000	3000 psi
6000	6000 psi

NPT vs BSPT Thread Comparison

Feature	NPT	BSPT
Thread Angle	60° (Sellers form, flat crest)	55° (Whitworth form, rounded crest)
Taper	1:16	1:16
Governing Standard	ASME B1.20.1	BS 21 / BS EN 10226-1
Common Region	North America	Europe, UK, Middle East, Asia
Interchangeable With the Other	No	No

Carbon Steel Threaded Fittings Specifications

Parameter	Specification
Standard	ASTM A105, ASME B16.11
Size Range	NPS 1/8" to 4"
Pressure Class	2000#, 3000#, 6000#
Thread Type	NPT (ASME B1.20.1) or BSPT (BS 21 / BS EN 10226-1)
Thread Angle	NPT 60° (Sellers form); BSPT 55° (Whitworth form)
Taper	1:16 (both NPT and BSPT)
Hardness	137 to 197 HB
Certification	Mill Test Certificate EN 10204 3.1, 3.2 on request

Carbon Steel Threaded Pipe Fittings Dimensions Chart

DN	NPS	Center to End NPT Elbow, NPT Tee, NPT Cross A Class 2000	Center to End NPT Elbow, NPT Tee, NPT Cross A Class 3000	Center to End NPT Elbow, NPT Tee, NPT Cross A Class 6000	Center to End 45 Deg Elbow C Class 2000	Center to End 45 Deg Elbow C Class 3000	Center to End 45 Deg Elbow C Class 6000	O.D. of Band H Class 2000	O.D. of Band H Class 3000	O.D. of Band H Class 6000	Min. Wall Thick. G Class 2000	Min. Wall Thick. G Class 3000	Min. Wall Thick. G Class 6000	Length of Thread. Minimum (1) B	Length of Thread. Minimum (1) L2
6	1/8	21	21	25	17	17	19	22	22	25	3.18	3.18	6.35	6.4	6.7
8	1/4	21	25	28	17	19	22	22	25	33	3.18	3.30	6.60	8.1	10.2
10	3/8	25	28	33	19	22	25	25	33	38	3.18	3.51	6.98	9.1	10.4
15	1/2	28	33	38	22	25	28	33	38	46	3.18	4.09	8.15	10.9	13.6
20	3/4	33	38	44	25	28	33	38	46	56	3.18	4.32	8.53	12.7	13.9
25	1	38	44	51	28	33	35	46	56	62	3.68	4.98	9.93	14.7	17.3
32	1-1/4	44	51	60	33	35	43	56	62	75	3.89	5.28	10.59	17.0	18.0
40	1-1/2	51	60	64	35	43	44	62	75	84	4.01	5.56	11.07	17.8	18.4
50	2	60	64	83	43	44	52	75	86	102	4.27	7.14	12.09	19.0	19.2
65	2-1/2	76	83	95	52	52	64	92	102	121	5.61	7.65	15.29	23.6	28.9
85	3	86	95	106	64	64	79	109	121	146	5.99	8.84	16.64	25.9	30.5
100	4	106	114	114	79	79	79	146	152	152	6.55	11.18	18.67	27.7	33.0

DN	NPS	End to End Couplings W Class 3000&Class 6000	End to End Caps P Class 3000	End to End Caps P Class 6000	O.D. D Class 3000	O.D. D Class 6000	End Wall Thick. G Minimum Class 3000	End Wall Thick. G Minimum Class 6000	Length of Thread. Minimum (1) B	Length of Thread. Minimum (1) L2
6	1/8	32	19	…	16	22	4.8	…	6.4	6.7
8	1/4	35	25	27	19	25	4.8	6.4	8.1	10.2
10	3/8	38	25	27	22	32	4.8	6.4	9.1	10.4
15	1/2	48	32	33	28	38	6.4	7.9	10.9	13.6
20	3/4	51	37	38	35	44	6.4	7.9	12.7	13.9
25	1	60	41	43	44	57	9.7	11.2	14.7	17.3
32	1-1/4	67	44	46	57	64	9.7	11.2	17.0	18.0
40	1-1/2	79	44	48	64	76	11.2	12.7	17.8	18.4
50	2	86	48	51	76	92	12.7	15.7	19.0	19.2
65	2-1/2	92	60	64	92	108	15.7	19.0	23.6	28.9
80	3	108	65	68	108	127	19.0	22.4	25.9	30.5
100	4	121	68	75	140	159	22.4	28.4	27.7	33.0

Carbon Steel Threaded Fittings Pressure Rating

Threaded pipe fittings typically have pressure ratings of either 3000 psi or 6000 psi, depending on industry standards such as ASME B16.11, MSS SP-79/83/95, or BS 3799, and can vary dependent on the material, thread type, and size of the fitting.

ASME B16.11 Pressure-Temperature

Temperature (oF)	Temperature (oC)	Class 150	Class 300 1/4 - 1 inch.	Class 300 1 1/4 - 2 inch.	Class 300 2 1/2 - 3 inch.
-20 to 150	-29 to 66	300	2000	1500	1000
200	93	265	1785	1350	910
250	121	225	1575	1200	825
300	149	185	1360	1050	735
350	177	150	1150	900	650
400	204	-	935	750	560
450	232	-	725	600	475
500	260	-	510	450	385
550	288	-	300	300	300

Carbon Steel Threaded Forged Fittings Weight Chart

Size Product	Class	1/4”	1/2”	2”	3/4”	1/8”	4”	1”	1-1/2”	3/8”	1-1/4”	2-1/2”	3”
45 Elbow	2000	0.08	0.20	1.41	0.27	0.09	8.96	0.41	0.82	0.10	0.68	3.46	5.44
45 Elbow	3000	0.12	0.34	2.23	0.56	0.09	8.96	0.94	2.05	0.24	1.03	3.71	5.97
45 Elbow	6000	0.27	0.63	4.37	1.07	0.11	11.36	1.27	2.54	0.39	2.24	7.01	14.16
90 Elbow	2000	0.08	0.25	1.70	0.35	0.10	10.21	0.53	1.06	0.13	0.82	3.14	4.81
90 Elbow	3000	0.14	0.43	2.92	0.69	0.10	14.85	1.14	2.63	0.29	1.42	5.99	8.88
90 Elbow	6000	0.33	0.80	7.31	1.31	0.17	15.76	1.61	3.79	0.45	2.93	9.88	17.73
Tee	2000	0.12	0.31	2.16	0.43	0.13	14.74	0.69	1.39	0.17	1.07	4.11	6.12
Tee	3000	0.20	0.56	3.53	0.92	0.13	19.13	1.49	3.27	0.38	1.76	6.99	10.19
Tee	6000	0.45	0.98	7.88	1.65	0.20	18.53	2.17	4.71	0.63	3.74	13.11	21.70
Cross	2000	0.14	0.39	2.65	0.54	0.17	16.35	0.83	1.75	0.21	1.26	5.26	7.58
Cross	3000	0.26	0.72	4.27	1.06	0.17	21.93	1.79	3.93	0.44	2.13	8.51	12.45
Half Coupling	3000	0.02	0.06	0.70	0.10	0.02	3.11	0.23	0.54	0.03	0.34	1.13	1.68
Half Coupling	6000	0.06	0.16	1.70	0.24	0.07	5.02	0.45	0.96	0.09	0.55	2.10	3.05
Round Head Plug		0.45	0.12	1.47	0.20	0.02	6.24	0.34	0.79	0.07	0.55	2.34	3.26
Red Coupling	3000	0.05	0.13	1.37	0.19	0.05	5.44	0.39	0.99	0.06	0.68	2.07	3.08
Red Coupling	6000	0.06	0.31	3.40	0.41	0.08	10.04	0.85	1.81	0.18	1.05	4.20	6.10
Full Coupling	3000	0.04	0.13	1.40	0.19	0.05	6.28	0.45	1.07	0.06	0.81	2.29	3.38
Full Coupling	6000	0.13	0.34	2.87	0.50	0.08	10.04	0.87	1.94	0.20	1.09	4.20	6.10
Cap	3000	0.04	0.11	1.09	0.18	0.02	4.84	0.37	0.72	0.05	0.62	2.22	3.50
Cap	6000	0.06	0.26	2.23	0.40	0.06		0.71	0.77	0.09	0.59
Street Elbow	3000	0.11	0.31	2.91	0.53	0.13		1.02	2.01	0.22	1.13
Union	3000	0.28	0.34	2.43	0.48	0.28	12.00	0.77	1.63	0.24	1.03	3.63	5.27
Square Head Plug		0.01	0.05	0.63	0.09	0.01	3.83	0.16	0.38	0.03	0.27	0.96	1.53
Hex Nipple	3000	0.04	0.09	1.03	0.15	0.03	4.00	0.47	0.62	0.05	0.45	1.51	2.22
Hex Head Plug		0.03	0.07	1.03	0.14	0.01	5.20	0.22	0.59	0.05	0.44	1.80	2.60
Hex Head Bushing		0.01	0.03	0.45	0.05		3.20	0.09	0.34	0.01	0.25	0.60	1.16

Types of Carbon Steel Threaded Fittings

Carbon Steel Threaded Union

Carbon Steel Threaded Unequal Tee

Carbon Steel Threaded Unequal Cross

Carbon Steel Threaded Reducing Coupling

Carbon Steel Threaded Half Coupling

Carbon Steel Threaded Full Coupling

Carbon Steel Threaded Equal Tee

Carbon Steel Threaded Equal Cross

Carbon Steel Threaded Cap

Carbon Steel Swage Nipple

Carbon Steel Square Head Plug

Carbon Steel Hex Nipple

Carbon Steel Hex Head Plug

Carbon Steel Hex Head Bushing

Carbon Steel 90 Deg Threaded Elbow

Carbon Steel 45 Deg Threaded Elbow

Applications of Carbon Steel Threaded Fittings

Utility and drain lines
Sampling connections
Low to medium pressure small bore piping
Instrument and gauge connections
Pump and valve end connections
Maintenance friendly joints requiring frequent dismantling

Threaded vs Socket Weld Fittings - Which to Choose

Threaded and socket weld fittings often serve the same size range but suit different maintenance needs. Use this table to decide.

Criteria	Threaded Fittings	Socket Weld Fittings
Joint Type	Mechanical thread (NPT/BSPT)	Fillet weld into socket
Ease of Dismantling	High, unscrews for maintenance	Low, must be cut out
Maximum Pressure Class	6000	9000
Typical Use Case	Utility lines, instrumentation, frequently serviced joints	Permanent high pressure or vibration prone joints
Learn More	This page	Carbon Steel Socket Weld Fittings

Frequently Asked Questions

What thread standards are available?

Both NPT (American) and BSPT (British/ISO) thread forms can be supplied; specify your preferred standard when ordering.

What is the maximum pressure class for threaded fittings?

Threaded carbon steel fittings under ASME B16.11 are rated up to Class 6000; for higher pressure, socket weld fittings up to Class 9000 are recommended.

Can NPT and BSPT threads be used together?

No, NPT and BSPT threads are not interchangeable; NPT uses a 60 degree angle with a flat crest while BSPT uses a 55 degree angle with a rounded crest, so mixing them causes leaks or thread damage even though both use the same 1:16 taper.

Do threaded fittings need sealant or tape?

Yes, since threaded joints seal through mechanical interference alone, PTFE tape or a suitable thread sealant is normally applied to ensure a leak free connection.

What is the minimum order quantity for threaded fittings?

MOQs vary by size and class; share your bill of materials with our sales team for a size wise quotation and lead time.

Can threaded fittings be reused after removal?

Threaded fittings can often be reused if the threads are undamaged, which is one of the key advantages of a mechanical joint over a welded one, though a fresh application of sealant is recommended.