Stub-End

STUB END | LAP JOINT CARBON,ALLOY, STAINLESS STEEL LONG/SHORT PATTERN STUB ENDS/LAP JOINTS

Description

Stub end fittings are used with lap joint flanges to form detachable flange connections in piping systems. A stub end is welded to the pipe while the lap joint flange rotates freely around the stub end, allowing easy alignment of bolt holes during installation. This type of connection is widely used in stainless steel and alloy piping systems where frequent maintenance, inspection or replacement is required.

In industrial piping systems, stub ends are typically installed together with pipe flanges, pipes and butt weld fittings to complete piping systems and flange assemblies. Lap joint flange connections using stub ends are commonly used in low-pressure systems, corrosion-resistant piping systems and systems requiring frequent dismantling.

They are widely used in petrochemical plants, offshore platforms, refineries, LNG facilities, power plants and heavy industrial piping systems.

Specifications / Standards

Manufactured according to international piping and flange standards to ensure dimensional compatibility with lap joint flanges and piping systems.

Typical standards include:

ASME B16.9 – Factory-Made Butt Welding Fittings
MSS SP-43 – Wrought Stainless Steel Butt Weld Fittings
ASME B16.5 – Pipe Flanges and Flanged Fittings
ASME B31.3 – Process Piping
ASTM A403 – Stainless Steel Pipe Fittings
ASTM A815 – Duplex Stainless Steel Pipe Fittings
ASTM B366 – Nickel Alloy Pipe Fittings
EN 10204 – Inspection Certificates

Commonly supplied together with stainless steel pipe fittings and lap joint flanges for complete flange connection assemblies.

Material Grades

Can be manufactured in carbon steel, stainless steel, duplex stainless steel and nickel alloys depending on corrosion conditions and service requirements.

Carbon Steel

ASTM A234 WPB
ASTM A420 WPL6

Stainless Steel

ASTM A403 WP304 / 304L
ASTM A403 WP316 / 316L
ASTM A403 WP321
ASTM A403 WP347

Duplex & Super Duplex

ASTM A815 UNS S31803
ASTM A815 UNS S32205
ASTM A815 UNS S32750
ASTM A815 UNS S32760

Nickel Alloys

ASTM B366 UNS N06625
ASTM B366 UNS N08825
ASTM B366 UNS N10276

Material grades are selected according to project specifications, corrosion allowance and operating conditions.

Size Range

Typical size range for stub ends:

Size Range: 1/2″ to 48″
Wall Thickness: SCH 5S – SCH XXS
Types:
Short Pattern Stub End
Long Pattern Stub End
Lap Joint Stub End
End Type:
Butt Weld End
Lap Joint Face

Special sizes and custom stub ends can be manufactured according to project drawings and piping specifications.

Manufacturing Process

The manufacturing process for stub ends typically includes:

Raw material pipe selection
Cutting
Forming the lap joint face
Heat treatment
Bevel machining
Surface treatment (Pickling / Passivation / Shot blasting)
Marking and traceability identification
Inspection and testing
Packing and shipment

All materials are fully traceable from raw material heat number to final inspection documentation.

Inspection & Testing

Inspection and testing may include:

Visual inspection
Dimensional inspection
PMI (Positive Material Identification)
Mechanical testing
Hardness testing
Ultrasonic testing (UT)
Dye penetrant testing (PT)
Hydrostatic testing (if required)
Third-party inspection (SGS / BV / TUV / DNV)

Inspection certificates can be supplied according to EN 10204 3.1 or 3.2.

Applications / Industries

Widely used in industrial piping systems across various industries:

Oil & Gas
Petrochemical
Offshore & FPSO
LNG & Gas Processing
Power Plants
Nuclear Industry
Chemical Plants
Desalination Plants
Shipbuilding
Heavy Industry

Commonly used in corrosion-resistant piping systems, stainless steel piping systems and piping systems requiring frequent dismantling and maintenance.

Packaging & Delivery

Packed to prevent damage during transportation and storage.

Typical packing methods include:

Wooden cases
Plywood boxes
Pallets
Waterproof wrapping
End protection
Heat number marking
Packing list and traceability documentation

Export packing is suitable for sea freight, air freight and project site delivery.

Why Choose Us

We supply stub ends for industrial piping projects with complete material traceability, inspection documentation and project packaging requirements.

Our stub ends are supplied to EPC contractors, fabrication workshops, offshore projects, petrochemical plants and power plant projects where documentation, quality control and delivery reliability are critical.

We support complete piping material supply including pipes, fittings, flanges, forgings and prefabrication pipe spools, ensuring compatibility between all piping components and project specifications.