Carbon Steel ASME B16.9 Buttweld Fittings Manufacturer & Exporter

Solitaire Overseas manufactures large bore carbon steel buttwelding fittings dimensioned to ASME B16.9 and supplied in ASTM A234 Grade WPB or WPC material. Unlike forged small bore fittings, these are wrought from seamless or welded pipe, plate or forgings and joined by full penetration butt weld, making them the standard choice for continuous process piping, cross country pipelines and large diameter plant runs. Our ASME B16.9 range covers NPS 1/2 inch to 48 inch across the full family of elbows, tees, reducers, caps and crosses, with full mill test certification and dimensional inspection on every batch.

Types of Carbon Steel ASME B16.9 Fittings

90° Long Radius (LR) Elbow — center to end dimension = 1.5 × NPS
90° Short Radius (SR) Elbow — center to end dimension = 1.0 × NPS
45° Elbow (Long Radius)
180° Long Radius Return
Equal Tee
Reducing Tee
Straight Cross
Reducing Cross
Concentric Reducer
Eccentric Reducer
Cap
Lap Joint Stub End

Need small bore socket weld or threaded fittings instead?

See our Carbon Steel Forged Fittings range (ASME B16.11, NPS 1/8" to 4"), or reach out for a combined quote covering both large and small bore requirements.

Technical Data

Specifications Chemical Composition Mechanical Properties Approximate International Equivalents

Carbon Steel ASME B16.9 Fittings Specifications

Parameter	Specification
Standard	ASME B16.9 (dimensions, tolerances, ratings, testing, marking); ASME B16.28 for short radius elbows and returns
Material Specification	ASTM A234 Grade WPB / WPC (most common carbon steel grades); alloy grades WP1 through WP91 available on request
Size Range	NPS 1/2" to 48" (DN 15 to DN 1200)
Wall Thickness	Any producible wall thickness; commonly specified by schedule per ASME B36.10M
End Connection	Butt weld — square cut, plain bevel or compound bevel per ASME B16.25
Manufacturing	Wrought from seamless or welded pipe, plate, or forgings
Fitting Types	90° LR/SR elbows, 45° elbows, equal & reducing tees, concentric/eccentric reducers, caps, straight & reducing crosses, lap joint stub ends
Heat Treatment	Not mandatory for standard hot formed WPB/WPC fittings under 1800°F; required for cold formed fittings and NPS 12+ locally heated fittings
Certification	Mill Test Certificate EN 10204 3.1, 3.2 on request

Chemical Composition (ASTM A234, %)

Element	WPB max	WPC max
Carbon	0.30 (0.35 from 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)

Approximate International Equivalents

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

Applications of Carbon Steel ASME B16.9 Fittings

Refinery and petrochemical process piping
Power plant steam and feedwater lines
Cross country and plant pipeline systems
Water and gas distribution networks
Structural, marine and general industrial piping

Long Radius vs Short Radius Elbows - Which to Choose

Both elbow types are covered under the same ASME B16.9 standard but serve different layout requirements. Use this table to pick the right one.

Criteria	Long Radius (LR) Elbow	Short Radius (SR) Elbow
Center-to-End Dimension	1.5 × NPS	1.0 × NPS
Pressure Drop	Lower	Higher
Typical Availability	Standard, most widely stocked	Used where space is constrained
Typical Use Case	General process piping, long runs	Tight layouts, skids, congested routing

Frequently Asked Questions

What is the difference between ASME B16.9 and ASME B16.11 fittings?

ASME B16.9 covers large bore, factory made wrought buttwelding fittings from NPS 1/2 through NPS 48, shaped from pipe, plate or forgings for full penetration butt weld joints. ASME B16.11 covers small bore forged socket weld and threaded fittings up to NPS 4, machined from solid bar stock and rated by pressure class rather than schedule.

What material grade is typically used for ASME B16.9 fittings?

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

Are ASME B16.9 fittings seamless or welded?

Both. The standard applies equally to fittings shaped from seamless pipe, welded pipe, plate or forgings, provided the finished fitting meets the specified dimensional tolerances; welded construction is marked with a supplemental W.

What size range does ASME B16.9 cover?

ASME B16.9 covers NPS 1/2 inch through NPS 48 inch, equivalent to DN 15 through DN 1200, and applies to any producible wall thickness rather than a fixed schedule range.

Does ASME B16.9 specify pressure ratings for fittings?

No. ASME B16.9 sets overall dimensions, tolerances, testing and marking only. Allowable pressure at a given temperature is calculated separately under the governing piping code, such as ASME B31.3, based on the material grade and actual wall thickness ordered.

What is the difference between long radius and short radius elbows?

A long radius elbow has a center to end dimension of 1.5 times the nominal pipe size, giving a smoother direction change and lower pressure drop, while a short radius elbow uses 1.0 times the nominal size for tighter, space constrained routing.

Get a quote for carbon steel ASME B16.9 buttweld fittings from Solitaire Overseas, or visit our Carbon Steel Pipe Fittings hub to compare forged, buttweld, high yield and material grade options side by side.