Butt-Weld Pipe Caps

Butt-weld caps close the end of a pipe or header with a full-strength weld — permanent blanking for hydro test isolation, future tie-ins and dead-leg ends. NPS 1/2" to 48" in every standard schedule.

NPS 1/2" – 48"Sch 10 – 160 / STD / XS / XXSASME B16.9 / B16.11 small boreA234 WPB · A420 WPL6 · A403

Butt-Weld Pipe Caps

A butt-weld cap permanently closes the end of a pipe — for hydrostatic test blanking, future tie-ins, vessel heads and dead-leg terminations. CREATEEL supplies caps from 1/2" to 48" in elliptical (2:1), torispherical and flat geometries, in wall schedules matched to the connecting pipe.

Small and medium caps are die-pressed from pipe or plate in one stroke; large diameter caps are cold or hot spun. Every cap is dimensionally checked for height, crown radius and lip straightness before coating and packing.

Every CREATEEL fitting is shipped with full heat-number traceability from raw material certificate to the stamped marking on the piece itself. Dimensional reports, heat treatment charts and EN 10204 3.1 inspection certificates are issued as standard, with 3.2 certification by third-party inspection (SGS, BV, TÜV) available on request before shipment.

Technical Specifications

Applicable Standards

Standard	Scope	Note
ASME B16.9	Butt-welding caps	Dimensions & tolerances
ASME B16.11	Small-bore forged caps	Socket/threaded
MSS SP-43	Light-wall stainless caps	Sch 5S/10S
EN 10253-2 / -4	Wrought caps	European
GB/T 12459	Steel fittings	Chinese
GOST 17379	Caps	Russian

Dimensions (ASME B16.9)

NPS	OD (mm)	Wall (schedule)
1/2″–2″	21.3–60.3	Sch 10–160, STD, XS
2-1/2″–8″	73.0–219.1	Sch 10–160
10″–24″	273.0–609.6	Sch 10–160, XS, XXS
Stainless light-wall	per MSS SP-43	Sch 5S/10S

Outside diameter matches the pipe; inside depth per ASME B16.9. Dished ends for vessels quoted separately.

Material Grades

Family	Grade	Spec
Carbon steel	A234 WPB	ASTM A234
Low-temperature	A420 WPL6	ASTM A420
Alloy	A234 WP11 / WP22	ASTM A234
Stainless	A403 WP304 / 316L	ASTM A403
Forged small-bore	A105 / A182	ASTM A105 / A182

Coating & Surface Treatment

Black / varnished mill finish.
Hot-dip galvanized to ASTM A153.
3PE / FBE coating for buried ends.
Pickled & passivated stainless.

Packing & Shipping

Plywood cases or pallets, seaworthy packing.
End faces protected.
EN 10204 3.1 MTC; 3.2 with SGS / BV / TÜV on request.
MOQ 5 t per item; lead time 15–30 days.

Types & Range

Butt-weld cap

Schedule-matched domed end — the standard permanent blank.

Forged SW cap

Socket-weld 3000#/6000# for small bore.

Forged TH cap

Threaded cap for temporary or low-pressure blanking.

Materials & Standards

A234 WPB, WP11/WP22/WP91, A420 WPL6, A403 WP304L/316L; forged caps in A105 / A350 LF2 / A182 to match the small-bore system.

Standards in brief: ASME B16.9 (butt-weld), ASME B16.11 (forged); EN 10204 3.1 / 3.2 certification available.

Manufacturing Process

Press and spin forming of ASME B16.9 caps and ASME VIII dished ends — one-piece heads, no welds in the pressure envelope.

Blank Preparation

Pipe or circular plate blank cut with forming allowance; edges inspected for laminations.

Heating

Hot forming at 900–1050°C for carbon and alloy; cold forming for thin stainless.

Die Pressing

Hydraulic press forms the dome in matched dies; deep heads pressed in steps with intermediate annealing.

Spin Forming

Large diameters spun for round, true heads without heavy tooling.

Trimming & Beveling

Edge trimmed to lip height; weld bevel cut per B16.25.

Heat Treatment

Normalizing or solution annealing per grade and forming temperature ratio.

Testing & NDT

UT wall check at the knuckle, MT for hot-formed carbon, dimensional report of height and crown.

Marking & Packing

Heat number and schedule stencilled on crown; faces protected with strippable coating.

Applications

PRODUCT applications copy

OIL & GAS

Line & Pigging Ends

Caps terminate and re-open piggable lines cleanly.

✓ ASME B16.9 / API 5L

VESSELS

Vessel & Nozzle Closures

Caps and dished ends close pressure-equipment nozzles.

✓ A234 WPB

WATER

Water & Treatment

Line ends for potable and process networks.

✓ EN 10253 / GB/T 12459

CHEMICAL

Process & Petrochemical

Alloy/stainless caps for corrosive duty.

✓ A403 WP316L / NACE

POWER

Power Plant Piping

High-temp caps for boiler and turbine auxiliaries.

✓ A234 WP11 / ASME B31.1

CONSTRUCTION

HVAC & Building Services

Riser and skid line terminations.

✓ A234 WPB

Frequently Asked Questions

What is a buttweld cap used for?

It closes the end of a pipe — for pressure testing, temporary blanking or as a permanent end cap. Because it is welded on, the line can be re-extended later by cutting it off.

What size range do you supply?

NPS 1/2″–48″ (DN15–DN1200), seamless up to 24″, welded above; schedules Sch 10–160, STD, XS, XXS.

What materials are available?

ASTM A234 WPB, A420 WPL6, A403 WP304L/316L, A234 WP11/WP22/WP91 and duplex on request.

What shape is a B16.9 cap?

An elliptical dished head per ASME B16.9; wall thickness matches the pipe schedule so the cap is as strong as the pipe it closes.

Seamless or welded caps?

Both are available. Seamless dominates up to 24″; welded caps are standard for large-diameter, thin-wall pipe.

How do you control quality?

100% dimensional check (OD, height, thickness), hardness and PMI sampling, hydrostatic or NDT on request; EN 10204 3.1 MTC.

What surface treatment is available?

Anti-rust oil or varnish as standard; FBE, 3LPE or hot-dip galvanizing on request. Ends plain or beveled to match your welding preparation.

What is your MOQ and lead time?

Flexible MOQ — trial orders welcome. Stock 7–15 days; production 20–35 days depending on quantity.

Can caps be reused when the line is extended?

The cap itself is sacrificed when cut out — keep a spare cap on site for future tie-ins; it is the cheapest insurance for the line.

What marking and documentation come with the goods?

Heat number, size, schedule and grade marked per MSS SP-25; MTC 3.1 and packing list with every shipment.

Need Butt-Weld Pipe Caps?

Send us your sizes, schedule and material — our engineers will come back with a detailed quotation within 24 hours on working days.

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