316 Stainless Steel 150# Flat Face Lap Joint Flange

Product Highlights

• ASTM A/SA182 F316/L stainless steel construction
• ASME B16.5 dimensional configuration
• Class 150 pressure class
• Lap Joint flange design
• Flat Face (FF) configuration
• Designed for use with compatible lap joint stub ends
• Loose-back flange allows rotational alignment
• Forged stainless steel construction
• Enhanced corrosion resistance
• Useful where frequent disassembly or alignment is required
• Suitable for industrial, chemical, water treatment, food processing, marine, and process piping applications

These lap joint flanges are forged from dual-certified ASTM A/SA182 F316/L stainless steel for strength, durability, and enhanced corrosion resistance in demanding piping environments.

The flange is designed to work with a compatible lap joint stub end. The stub end is welded to the pipe while the flange remains loose behind the stub-end lap, allowing the flange to rotate independently around the pipe.

This loose-back construction helps simplify bolt-hole alignment during installation and can make system disassembly and maintenance easier. The flange transfers bolting load to the stub-end lap while the stub end provides the process-facing sealing surface.

A lap joint flange is used together with a compatible stub end. The stub end is welded directly to the pipe, while the flange slides over the pipe and remains loose behind the formed lap of the stub end.

During assembly, the loose flange can be rotated so its bolt holes align with the mating flange or equipment connection. When the bolting is tightened, the flange bears against the back of the stub-end lap and transfers the clamping load to the sealing joint.

This design can be especially useful in piping systems that require frequent maintenance, inspection, cleaning, or disassembly because the flange itself is not permanently welded into a fixed orientation.

The Flat Face (FF) configuration provides a flat flange contact surface rather than a raised sealing face. In a lap joint assembly, the actual process sealing surface is generally provided by the compatible stub end used with the flange.

Always confirm the required flange face configuration, stub-end style, gasket arrangement, mating flange, bolting, and applicable piping-system requirements before installation.

316/L stainless steel contains molybdenum, which contributes to improved resistance to pitting and localized corrosion in many environments compared with 304-series stainless steel.

This makes 316/L stainless steel a common material choice for chemical processing, water treatment, marine, coastal, food processing, and other piping applications where increased corrosion resistance is desirable.

Actual material suitability depends on the process media, chemical concentration, temperature, pressure, environmental exposure, and applicable piping-system requirements. Compatibility should be verified for the intended service.

• Confirm the correct nominal pipe size before installation.
• Verify that the lap joint flange is compatible with the selected stub end.
• Confirm that the stub end material and dimensions are appropriate for the piping system.
• Install and weld the stub end according to the applicable welding procedure and piping-code requirements.
• Position the lap joint flange behind the stub-end lap before final assembly.
• Rotate the flange as needed to align bolt holes with the mating flange.
• Select an appropriate gasket arrangement for the stub end and mating flange configuration.
• Use appropriate flange bolts, studs, nuts, and related hardware.
• Confirm material compatibility with the process fluid and operating environment.
• Verify applicable pressure and temperature requirements before installation.
• Inspect flange, stub-end, and sealing surfaces for damage or contamination before assembly.
• Follow appropriate flange-bolting and gasket-installation procedures.
• Installation and welding should be performed by qualified personnel familiar with lap joint piping systems.