Baojing Steel supplies stainless steel Lap Joint Stub Ends designed for use with lap joint flanges and suitable backing flanges. They provide a practical solution for piping systems requiring easy alignment, frequent disassembly and flange reuse.
The stub end is butt-welded to the pipe, while the loose flange rotates around the stub end. This design makes flange alignment easier during installation and maintenance, while allowing the flange to be reused.
The loose flange can rotate freely around the stub end, making bolt-hole alignment faster and easier during installation.
The backing flange does not need to be welded directly to the pipe and can be reused when the piping configuration or maintenance requirements change.
The stub end can be manufactured from corrosion-resistant stainless steel or duplex grades, making it suitable for demanding process environments.
Particularly suitable for piping systems that require regular inspection, cleaning, maintenance or equipment replacement.
The fluid-contacting stub end can be made from a high-alloy material while the backing flange can be selected separately according to the project requirements, helping optimize material and installation costs.
Type A stub ends are designed specifically for use with standard lap joint flanges. The outside fillet radius is designed to accommodate the lap joint flange, providing proper mating between the stub end and flange.
Recommended for:
General lap joint flange connections and corrosion-resistant piping systems.
Type B stub ends are designed to work with standard slip-on flanges used as backing flanges. Their smaller outside fillet radius allows the slip-on flange to fit correctly around the stub end.
Recommended for:
Cost-conscious piping systems and applications using slip-on flanges as backing flanges.
The Type A / Type B selection should always match the flange configuration and applicable project standard. MSS SP-43 specifically distinguishes Type A for lap-joint flanges and Type B for slip-on flanges.
| Grade | Recommended Applications |
|---|---|
| 304 / 304L | General industrial, food & beverage, water systems |
| 316 / 316L | Chemical, marine and chloride-containing environments |
| 321 | Elevated-temperature piping |
| 310S | High-temperature and oxidation-resistant applications |
| 2205 Duplex | High strength and chloride resistance |
| 2507 Super Duplex | Severe corrosion, offshore and seawater applications |
| 904L | Highly corrosive chemical environments |
For duplex and high-alloy applications, material selection should be based on the process medium, temperature, pressure and project specification.
Lap Joint Stub Ends can be supplied according to major international standards, including:
ASME B16.9
Factory-Made Wrought Buttwelding Fittings
MSS SP-43
Wrought Stainless Steel Butt-Welding Fittings for Low-Pressure, Corrosive Applications
ASTM A403 / A403M
Wrought Austenitic Stainless Steel Piping Fittings
ASTM A815 / A815M
Wrought Ferritic, Ferritic/Austenitic and Martensitic Stainless Steel Piping Fittings
Other EN, DIN, JIS and GB/T specifications are available according to project requirements. MSS SP-43 is particularly relevant to stainless steel butt-welding fittings and stub ends for corrosion-resistant, lower-pressure applications.
| Item | Available Options |
|---|---|
| Product | Lap Joint Stub End |
| Type | Type A / Type B |
| Size | NPS 1/2" – 24" & Customized |
| Wall Thickness | SCH 5S, 10S, 40S, 80S & Custom |
| Material | 304/304L, 316/316L, 321, 310S, 2205, 2507, 904L & More |
| Connection | Butt Weld |
| Length | Standard / Customized |
| End Preparation | ASME B16.25 or Customer Specification |
| Face | Machined / Serrated / Customized |
| Surface | Pickled / Polished / Bright / Custom |
MSS SP-43 provides dimensional requirements for stub ends and distinguishes the geometry used with lap-joint and slip-on backing flanges.
Process pipelines, refinery systems, offshore piping and fluid transfer systems.
Corrosive media, chemical processing lines, reactors and process equipment.
Seawater systems, offshore platforms, marine piping and cooling systems.
Hygienic process piping, beverage systems and food-processing equipment.
Process piping and systems requiring corrosion resistance and frequent maintenance.
Desalination, wastewater treatment and industrial water systems.
Cooling systems, utility piping and process equipment.
Baojing Steel can provide inspection and documentation according to project requirements:
Chemical Composition
Mechanical Properties
Dimensional Inspection
Visual & Surface Inspection
PMI – Positive Material Identification
Hardness Testing
MTC / EN 10204 3.1
Third-Party Inspection
Additional NDT upon request
International Standards
Products manufactured according to recognized international piping and fitting standards.
Wide Material Selection
From 304L and 316L to Duplex 2205, Super Duplex 2507 and 904L.
Customized Supply
Non-standard dimensions, special materials, wall thicknesses and inspection requirements can be supplied according to drawings and specifications.
Project-Oriented Service
We support material selection, dimensional confirmation, technical documentation and inspection requirements for complete piping projects.
From standard stainless steel to high-performance duplex and specialty alloys, Baojing Steel provides Lap Joint Stub Ends engineered for demanding piping systems worldwide.
