Carbon Steel Stub End Manufacturer & Exporter

Solitaire Overseas manufactures carbon steel stub ends dimensioned to MSS SP-43 and supplied in ASTM A234 Grade WPB or WPC material, for use with lap joint (Van Stone) flanges and backing rings. A carbon steel stub end presents a flat, machined face that a loose lap joint flange bears against, letting the flange rotate freely for bolt-hole alignment while only the stub end and pipe are exposed to the process media. This construction is widely used to save cost on alloy and stainless steel piping systems, since a carbon steel backing flange can be used with a stub end in the higher grade material. Our carbon steel stub end range covers NPS 1/2 inch to 24 inch, with full mill test certification and dimensional inspection on every batch.

Types of Carbon Steel Stub End

Type A Stub End (Long Pattern) — full flange-face contact for higher pressure classes and cyclic or critical service.
Type B Stub End (Short Pattern) — reduced contact face and lighter material section for economical, moderate-pressure duty.
Lap Joint Stub End — paired with a Class 150 to 2500 lap joint (Van Stone) flange for a fully bolted, rotatable joint.
Long Radius / Short Radius pattern stub ends — matched to the governing pipe schedule and mating flange facing.

Need buttweld elbows, tees, reducers or caps instead? See our Carbon Steel ASME B16.9 Pipe Fittings range, or reach out for a combined quote covering your full bill of materials.

Technical Data

Specifications Chemical Composition Mechanical Properties Equivalent Grades Dimension Chart Weights Type A vs Type B

Carbon Steel Stub End Specifications

Parameter	Specification
Standard	MSS SP-43 (dimensions, tolerances, testing, marking); ASME B16.9 general buttweld fitting practice
Material Specification	ASTM A234 Grade WPB / WPC (most common carbon steel grades); alloy grades available on request
Size Range	NPS 1/2" to 24" (standard MSS SP-43 range); larger sizes to NPS 48" on special request
Wall Thickness	Schedule 5S through XXS per ASME B36.10M / B36.19M, matching the mating pipe schedule
End Connection	One end plain bevel for butt weld; opposite end machined flat/radiused face for lap joint flange bearing
Manufacturing	Wrought from seamless or welded pipe
Fitting Types	Type A (long pattern), Type B (short pattern)
Heat Treatment	Not mandatory for standard hot formed WPB/WPC stub ends; required for cold formed pieces
Certification	Mill Test Certificate EN 10204 3.1, 3.2 on request

Chemical Composition

Element	WPB max	WPC max
Carbon	0.30 (0.35 bar/plate/forging)	0.35
Manganese	0.29 – 1.06	0.29 – 1.06
Phosphorus max	0.050	0.050
Sulfur max	0.058	0.058
Silicon min	0.10	0.10
Chromium max	0.40	0.40
Molybdenum max	0.15	0.15
Nickel max	0.40	0.40
Copper max	0.40	0.40
Vanadium max	0.08	0.08

Sum of Cu, Ni, Cr and Mo shall not exceed 1.00%. Carbon equivalent (C.E. = C + Mn/6 + (Cr+Mo+V)/5 + (Ni+Cu)/15) shall not exceed 0.50 for WPB and WPC, reported on the test report.

Mechanical Properties (ASTM A234)

Grade	Tensile Strength min	Yield Strength min	Elongation min
WPB	415 MPa (60 ksi)	240 MPa (35 ksi)	22% (longitudinal, round specimen)
WPC	485 MPa (70 ksi)	275 MPa (40 ksi)	22% (longitudinal, round specimen)

Equivalent Grades of Carbon Steel Stub End

ASTM Grade	EN	JIS
A234 WPB	P235GH / P265GH (EN 10253-2)	STPG370
A234 WPC	P280GH (EN 10253-2)	STPG410

Carbon Steel Stub End Dimension Chart

NOMINAL PIPE SIZE	OUTSIDE DIAMETER OF BARREL MINIMUM	OUTSIDE DIAMETER OF BARREL MAXIMUM	LENGTH (F) LONGPATTERN	LENGTH (F) SHORTPATTERN	RADIUS (R)	DIAMETER (G)
1/2″	20.5	22.8	76	51	3	35
3/4″	25.9	28.1	76	51	3	43
1″	32.6	35.0	102	51	3	51
1 1/4″	41.4	43.6	102	51	5	64
1 1/2″	47.5	49.9	102	51	6	74
2″	59.5	62.4	152	64	8	92
2 1/2″	72.2	75.3	152	64	8	105
3″	88.1	91.3	152	64	10	127
3 1/2″	100.8	104.0	152	76	10	140
4″	113.5	116.7	152	76	11	157
5″	140.5	144.3	203	76	11	186
6″	167.5	171.3	203	89	13	216
8″	218.3	222.1	203	102	13	270
10″	272.3	277.2	254	127	13	324
12″	323.1	328.0	254	152	13	381
14″	354.8	359.9	305	152	13	413
16″	405.6	411.0	305	152	13	470
18″	456.0	462.0	305	152	13	533
20″	507.0	514.0	305	152	13	584
22″	558.0	565.0	305	152	13	641
24″	609.0	616.0	305	152	13	692

Weights of Carbon Steel Stub End

Nominal Pipe Size	ANSI 5S	ANSI 10S	ANSI 40S	ANSI 80S	MSS 5S	MSS 10S	MSS 40S	MSS 80S
1/2	0.059	0.077	0.145	0.172	0.047	0.060	0.077	–
3/4	0.068	0.086	0.163	0.231	0.058	0.073	0.099	–
1	0.091	0.141	0.222	0.395	0.104	0.172	0.206	–
11/4	0.132	0.209	0.318	0.562	0.130	0.217	0.276	–
11/2	0.159	0.250	0.400	0.685	0.145	0.242	0.315	–
2	0.245	0.377	0.704	1.406	0.184	0.308	0.424	–
21/2	0.350	0.472	1.071	2.105	0.303	0.430	0.731	–
3	0.468	0.640	1.489	2.885	0.342	0.484	0.870	–
31/2	–	–	–	–	–	–	–	–
4	0.713	0.981	2.533	4.250	0.432	0.641	1.200	–
5	1.049	1.239	3.609	7.575	0.726	0.878	1.680	–
6	1.625	1.952	5.580	10.433	0.887	1.080	2.210	–
8	2.452	3.110	10.002	15.831	1.360	1.940	3.930	–
10	4.045	4.871	13.892	24.313	2.150	2.530	5.800	–
12	6.615	7.123	19.976	29.348	2.890	3.250	7.340	–

Carbon Steel Stub End Type A vs Type B

Criteria	Type A (Long Pattern)	Type B (Short Pattern)
Face Contact	Longer, full flange face bearing	Shorter, partial face bearing
Pressure Rating	Suited to Class 300 and above	Typically Class 150 – 300
Material Use	More material, higher unit cost	Less material, more economical
Typical Use Case	High pressure, critical or cyclic service	Low to moderate pressure, general service

Applications of Carbon Steel Stub End

Lap joint flanged connections requiring free rotation for bolt-hole alignment
Alloy and stainless steel piping systems using a carbon steel backing flange to reduce cost
Refinery and petrochemical piping needing frequent disassembly for maintenance
Cathodic protection and dielectric isolation joints
Cross country pipeline tie-ins and spool fabrication

Frequently Asked Questions

What is a carbon steel stub end used for?

A carbon steel stub end forms one half of a lap joint flanged connection. It is butt welded to the pipe while a separate, loose lap joint flange bears against its machined face, letting the flange rotate to align bolt holes without rotating the pipe itself.

What is the difference between Type A and Type B stub ends?

Type A is the long pattern with a full flange face contact area, suited to higher pressure classes, while Type B is the short pattern with a smaller contact face and less material, suited to lower pressure, general purpose service.

What standard governs carbon steel stub end dimensions?

MSS SP-43 sets the dimensions, tolerances, testing and marking requirements for carbon and stainless steel lap joint stub ends, covering both Type A and Type B patterns.

What material grade is used for carbon steel stub ends?

ASTM A234 Grade WPB is the most common carbon steel material, matching ASTM A106 Grade B pipe. Grade WPC is used where a higher minimum tensile and yield strength is required.

Can a stub end be used without a lap joint flange?

No. A stub end is designed to work together with a separate lap joint (Van Stone) flange that bears against its face; the two components are ordered and installed as a matched pair.

What size range is available for carbon steel stub ends?

Standard MSS SP-43 stub ends are produced from NPS 1/2 inch through NPS 24 inch, with larger sizes up to NPS 48 inch available on special request to match large bore pipeline requirements.

Get a quote for carbon steel stub ends from Solitaire Overseas, or visit our Carbon Steel Pipe Fittings hub to compare stub ends against buttweld and forged fitting options.