Carbon Steel Seamless Pipe Fittings Supplier

Solitaire Overseas supplies carbon steel seamless pipe fittings shaped directly from seamless ASTM A106 Grade B pipe rather than plate or fusion welded pipe stock. Manufactured in ASTM A234 Grade WPB and WPC to ASME B16.9 dimensions, seamless construction avoids a longitudinal weld seam along the fitting body, giving added metallurgical consistency for critical, high integrity piping systems. Covering NPS 1/2 inch to 48 inch across standard schedules, our seamless range includes elbows, tees, reducers and caps, each supplied with full mill test certification and dimensional traceability.

Need the welded construction alternative for larger diameters?

See our Carbon Steel Welded Pipe Fittings range, or contact our team to confirm which construction fits your project specification.

Chemical Composition, Mechanical Properties and Base Pipe Reference

Specifications Chemical Composition Mechanical Properties Base Pipe Reference

Carbon Steel Seamless Pipe Fittings Specifications

Parameter	Specification
Standard	ASTM A234 WPB/WPC (seamless construction)
Base Material	Seamless pipe, e.g. ASTM A106 Gr. B or API 5L Gr. B seamless
Dimensional Standard	ASME B16.9
Size Range	NPS 1/2" to 48"
Wall Thickness	SCH 10 to XXS
Heat Treatment	Normalized, or hot formed and air cooled
Testing	Hydrostatic test, radiography, PMI on request
Certification	Mill Test Certificate EN 10204 3.1, 3.2 on request

Chemical Composition (%)

Grade	C max	Mn	P max	S max	Si min
WPB	0.30	0.29 – 1.06	0.05	0.058	0.10
WPC	0.35	0.29 – 1.06	0.05	0.058	0.10

Mechanical Properties

Grade	Tensile Strength (MPa)	Yield Strength min (MPa)	Elongation min (%)
WPB	415 – 655	240	22
WPC	485 – 655	275	22

Base Pipe Standard Reference

Base Pipe Standard	Construction	Typical Use
ASTM A106 Grade B	Seamless	High temperature process piping
API 5L Grade B (seamless)	Seamless	Oil and gas pipelines
ASTM A53 Grade B (ERW)	Welded	General utility and structural piping (see our Welded Pipe Fittings range)

Types of Carbon Steel Seamless Pipe Fittings

90° and 45° Elbows (long and short radius) from seamless pipe
Equal and Reducing Tees from seamless pipe
Concentric and Eccentric Reducers from seamless pipe
Caps and Crosses from seamless pipe

Applications of Carbon Steel Seamless Pipe Fittings

Critical process piping
High integrity pipelines
Boiler feed and steam piping
High integrity offshore piping
Services requiring seam-free construction

Seamless vs Welded Fittings - Which to Choose

Seamless and welded fittings share the same ASTM A234 grade family but differ in base pipe route. Use this table to decide.

Criteria	Seamless Fittings	Welded Fittings
Base Material	Seamless pipe, no weld seam	Fusion welded pipe (ERW/EFW) or plate
Metallurgical Consistency	Uniform, no seam	Slight variation at weld seam, controlled by NDE
Typical Cost	Higher	More cost efficient
Typical Use Case	Critical, high integrity service	General utility, large diameter, structural piping
Learn More	This page	Carbon Steel Welded Pipe Fittings

Frequently Asked Questions

How is a seamless fitting different from a welded fitting?

Seamless fittings are shaped from pipe with no longitudinal weld seam, while welded fittings are made from fusion welded (ERW/EFW) pipe or plate; both are permitted under ASTM A234 but seamless is often preferred for critical service.

Does seamless construction cost more than welded?

Seamless fittings typically carry a price premium over welded construction for the same grade and size; confirm the specific requirement of your project code before selecting one over the other.

Are seamless fittings tested differently from welded fittings?

Both are tested to the same ASTM A234 chemical and mechanical requirements; welded fittings additionally undergo radiographic examination of the weld seam, which does not apply to seamless construction.

Which piping codes call for seamless construction specifically?

Some project specifications and codes for critical or high pressure hydrocarbon service mandate seamless construction; always check your governing piping class and client specification before ordering.

Can seamless and welded fittings be mixed in the same piping system?

Yes, provided each fitting individually meets the piping class and material specification called for at its location; many systems use welded fittings for general utility runs and seamless fittings for critical sections.

What documentation confirms seamless construction?

The mill test certificate references the parent pipe specification and heat number; on request we can provide additional traceability confirming seamless manufacture.