ASTM A403 316L Stainless Steel Stub Ends ASME B16.9 Lap Joint

ASTM A403 316L Stainless Steel Stub Ends ASME B16.9 Lap Joint

1.Product Description

Stainless Steel Stub Ends, also known in engineering as “Lap Joint Stub Ends” or “Von Roll-type flanged pipe ends,” are essentially stress-decoupled piping connection elements. Structurally, they separate the "pressure-retaining sealing function" from the "bolt-fastening function": the stub end withstands media pressure, corrosion, and erosion, while the lap joint flange ring exclusively provides bolt fastening loads. This design ensures that weld stresses and flange sealing stresses do not superimpose or interfere with each other when the piping system experiences extreme temperature differentials or mechanical vibrations. The products are manufactured in accordance with the three major global standard systems: American (ASME B16.9 / MSS SP-43), German (DIN EN 1092-1 / DIN 2673), and Japanese (JIS B2311 / B2220), enabling seamless integration into diverse export and domestic engineering projects. points.

2.Product Applications

This product is specifically engineered for the following four typical extreme service conditions and special scenarios:

1. Cryogenic and Ultra-Low Temperature Pipelines (-196℃ for LN₂/LNG): Used in LNG receiving terminals and air separation unit liquid nitrogen transfer lines. Austenitic stainless steel stub ends maintain excellent impact toughness at low temperatures. When paired with lap joint flanges, they effectively compensate for the massive axial contraction caused by cold shrinkage, preventing brittle fracture.

2. High-Temperature Heavy Oil and Steam-Traced Lines (≥400℃): Used in refinery atmospheric/vacuum distillation units and catalytic cracking high-temperature hydrocarbon gas lines. Long-pattern stub ends position the butt-weld far from the high-temperature lap stress zone, preventing flange sealing face failure due to high-temperature creep.

3. High-Erosion and Solid-Bearing Slurry Pipelines: Used in mining and metallurgy slurry transport and desulfurization limestone slurry circulation lines. The smooth inner bore of the stub end has no weld protrusions, eliminating slurry deposition and localized vortex erosion. After wear, only the stub end needs replacement, not the expensive large-bore flange.

4. Ultra-High Vacuum Systems (≤10⁻⁵ Pa): Used in semiconductor and photovoltaic industry vacuum chamber evacuation lines. The lap sealing face is ultra-finished and paired with oxygen-free copper gaskets or metallic C-rings to achieve extremely low outgassing rates and leak rates under ultra-high vacuum.

​3.Product Advantages

4.Key Product Specifications

FAQ

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2.How long is your delivery time? Generally it is 5-10 days if the goods are in stock. or it is 15-20 days if the goods are not in stock, it is according to quantity.

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